From 9ddbfd921e75a615844010b40e6732342ad26eaa Mon Sep 17 00:00:00 2001
From: Justine Tunney <jtunney@gmail.com>
Date: Fri, 22 Nov 2024 11:08:29 -0800
Subject: [PATCH] Introduce cosmo_futex_wait and cosmo_futex_wake

Cosmopolitan Futexes are now exposed as a public API.
---
 libc/calls/sig.c                              | 717 ------------------
 libc/cosmo.h                                  |   4 +
 libc/intrin/BUILD.mk                          |  14 +-
 libc/{calls => intrin}/checkcancel.c          |   0
 libc/{calls => intrin}/clock_gettime-mono.c   |   0
 libc/{calls => intrin}/clock_gettime-nt.c     |   0
 libc/{calls => intrin}/clock_gettime-sysv.c   |   0
 libc/{calls => intrin}/clock_gettime-xnu.c    |   0
 libc/{calls => intrin}/clock_gettime.c        |   0
 .../clock_gettime_monotonic_nt.c              |   0
 .../futex.c => libc/intrin/cosmo_futex.c      | 146 ++--
 libc/intrin/{futex.S => cosmo_futex_thunk.S}  |   4 +-
 libc/{calls => intrin}/getcontext.S           |   2 +-
 libc/{calls => intrin}/getcontext.inc         |   0
 libc/intrin/pthread_mutex_lock.c              |  26 +-
 libc/intrin/pthread_mutex_trylock.c           |  16 +-
 libc/intrin/pthread_mutex_unlock.c            |  14 +-
 libc/{calls => intrin}/restore.S              |   0
 libc/intrin/sig.c                             | 706 ++++++++++++++++-
 libc/intrin/sigblock.c                        |  53 ++
 libc/{calls => intrin}/sigcrashsig.c          |   0
 libc/{calls => intrin}/swapcontext.S          |   2 +-
 libc/{calls => intrin}/tailcontext.S          |   0
 libc/{calls => intrin}/timespec_add.c         |   0
 libc/{calls => intrin}/timespec_cmp.c         |   0
 libc/{calls => intrin}/timespec_frommicros.c  |   0
 libc/{calls => intrin}/timespec_frommillis.c  |   0
 libc/{calls => intrin}/timespec_fromnanos.c   |   0
 libc/{calls => intrin}/timespec_sub.c         |   0
 libc/{calls => intrin}/timespec_subz.c        |   0
 libc/{calls => intrin}/timespec_tomicros.c    |   0
 libc/{calls => intrin}/timespec_tomillis.c    |   0
 libc/{calls => intrin}/timespec_tonanos.c     |   0
 libc/{calls => intrin}/timespec_totimeval.c   |   0
 libc/{str => intrin}/timespectowindowstime.c  |   0
 libc/{calls => intrin}/timeval_add.c          |   0
 libc/{calls => intrin}/timeval_cmp.c          |   0
 libc/{calls => intrin}/timeval_frommicros.c   |   0
 libc/{calls => intrin}/timeval_frommillis.c   |   0
 libc/{calls => intrin}/timeval_sub.c          |   0
 libc/{calls => intrin}/timeval_subz.c         |   0
 libc/{calls => intrin}/timeval_tomicros.c     |   0
 libc/{calls => intrin}/timeval_tomillis.c     |   0
 libc/{calls => intrin}/timeval_toseconds.c    |   0
 libc/{str => intrin}/timevaltowindowstime.c   |   0
 libc/{calls => intrin}/ucontext.c             |   0
 .../vdsofunc.greg.c => intrin/vdsofunc.c}     |   0
 .../windowsdurationtotimespec.c               |   0
 .../windowsdurationtotimeval.c                |   0
 libc/{str => intrin}/windowstimetotimespec.c  |   0
 libc/{str => intrin}/windowstimetotimeval.c   |   0
 libc/str/BUILD.mk                             |   8 +-
 libc/thread/pthread_barrier_wait.c            |   6 +-
 libc/thread/pthread_cond_broadcast.c          |   4 +-
 libc/thread/pthread_cond_signal.c             |   4 +-
 libc/thread/pthread_cond_timedwait.c          |   7 +-
 libc/thread/pthread_exit.c                    |   6 +-
 libc/thread/pthread_timedjoin_np.c            |   7 +-
 libc/thread/sem_post.c                        |   4 +-
 libc/thread/sem_timedwait.c                   |   6 +-
 test/libc/thread/footek_test.c                |   2 -
 third_party/lua/lunix.c                       |   7 +-
 third_party/nsync/BUILD.mk                    |   1 -
 third_party/nsync/futex.internal.h            |  17 -
 third_party/nsync/mu_semaphore_futex.c        |  14 +-
 third_party/openmp/kmp_lock.cpp               |   6 +-
 66 files changed, 886 insertions(+), 917 deletions(-)
 delete mode 100644 libc/calls/sig.c
 rename libc/{calls => intrin}/checkcancel.c (100%)
 rename libc/{calls => intrin}/clock_gettime-mono.c (100%)
 rename libc/{calls => intrin}/clock_gettime-nt.c (100%)
 rename libc/{calls => intrin}/clock_gettime-sysv.c (100%)
 rename libc/{calls => intrin}/clock_gettime-xnu.c (100%)
 rename libc/{calls => intrin}/clock_gettime.c (100%)
 rename libc/{calls => intrin}/clock_gettime_monotonic_nt.c (100%)
 rename third_party/nsync/futex.c => libc/intrin/cosmo_futex.c (72%)
 rename libc/intrin/{futex.S => cosmo_futex_thunk.S} (97%)
 rename libc/{calls => intrin}/getcontext.S (98%)
 rename libc/{calls => intrin}/getcontext.inc (100%)
 rename libc/{calls => intrin}/restore.S (100%)
 create mode 100644 libc/intrin/sigblock.c
 rename libc/{calls => intrin}/sigcrashsig.c (100%)
 rename libc/{calls => intrin}/swapcontext.S (98%)
 rename libc/{calls => intrin}/tailcontext.S (100%)
 rename libc/{calls => intrin}/timespec_add.c (100%)
 rename libc/{calls => intrin}/timespec_cmp.c (100%)
 rename libc/{calls => intrin}/timespec_frommicros.c (100%)
 rename libc/{calls => intrin}/timespec_frommillis.c (100%)
 rename libc/{calls => intrin}/timespec_fromnanos.c (100%)
 rename libc/{calls => intrin}/timespec_sub.c (100%)
 rename libc/{calls => intrin}/timespec_subz.c (100%)
 rename libc/{calls => intrin}/timespec_tomicros.c (100%)
 rename libc/{calls => intrin}/timespec_tomillis.c (100%)
 rename libc/{calls => intrin}/timespec_tonanos.c (100%)
 rename libc/{calls => intrin}/timespec_totimeval.c (100%)
 rename libc/{str => intrin}/timespectowindowstime.c (100%)
 rename libc/{calls => intrin}/timeval_add.c (100%)
 rename libc/{calls => intrin}/timeval_cmp.c (100%)
 rename libc/{calls => intrin}/timeval_frommicros.c (100%)
 rename libc/{calls => intrin}/timeval_frommillis.c (100%)
 rename libc/{calls => intrin}/timeval_sub.c (100%)
 rename libc/{calls => intrin}/timeval_subz.c (100%)
 rename libc/{calls => intrin}/timeval_tomicros.c (100%)
 rename libc/{calls => intrin}/timeval_tomillis.c (100%)
 rename libc/{calls => intrin}/timeval_toseconds.c (100%)
 rename libc/{str => intrin}/timevaltowindowstime.c (100%)
 rename libc/{calls => intrin}/ucontext.c (100%)
 rename libc/{calls/vdsofunc.greg.c => intrin/vdsofunc.c} (100%)
 rename libc/{str => intrin}/windowsdurationtotimespec.c (100%)
 rename libc/{str => intrin}/windowsdurationtotimeval.c (100%)
 rename libc/{str => intrin}/windowstimetotimespec.c (100%)
 rename libc/{str => intrin}/windowstimetotimeval.c (100%)
 delete mode 100644 third_party/nsync/futex.internal.h

diff --git a/libc/calls/sig.c b/libc/calls/sig.c
deleted file mode 100644
index 7292b6701..000000000
--- a/libc/calls/sig.c
+++ /dev/null
@@ -1,717 +0,0 @@
-/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
-│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8                               :vi │
-╞══════════════════════════════════════════════════════════════════════════════╡
-│ Copyright 2022 Justine Alexandra Roberts Tunney                              │
-│                                                                              │
-│ Permission to use, copy, modify, and/or distribute this software for         │
-│ any purpose with or without fee is hereby granted, provided that the         │
-│ above copyright notice and this permission notice appear in all copies.      │
-│                                                                              │
-│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
-│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
-│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
-│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
-│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
-│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
-│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
-│ PERFORMANCE OF THIS SOFTWARE.                                                │
-╚─────────────────────────────────────────────────────────────────────────────*/
-#include "libc/sysv/consts/sig.h"
-#include "ape/sections.internal.h"
-#include "libc/calls/calls.h"
-#include "libc/calls/sig.internal.h"
-#include "libc/calls/state.internal.h"
-#include "libc/calls/struct/sigaction.h"
-#include "libc/calls/struct/siginfo.h"
-#include "libc/calls/struct/sigset.internal.h"
-#include "libc/calls/struct/ucontext.internal.h"
-#include "libc/calls/syscall_support-nt.internal.h"
-#include "libc/calls/ucontext.h"
-#include "libc/dce.h"
-#include "libc/errno.h"
-#include "libc/intrin/atomic.h"
-#include "libc/intrin/bsf.h"
-#include "libc/intrin/describebacktrace.h"
-#include "libc/intrin/dll.h"
-#include "libc/intrin/maps.h"
-#include "libc/intrin/strace.h"
-#include "libc/intrin/weaken.h"
-#include "libc/nt/console.h"
-#include "libc/nt/enum/context.h"
-#include "libc/nt/enum/exceptionhandleractions.h"
-#include "libc/nt/enum/processcreationflags.h"
-#include "libc/nt/enum/signal.h"
-#include "libc/nt/enum/status.h"
-#include "libc/nt/events.h"
-#include "libc/nt/runtime.h"
-#include "libc/nt/signals.h"
-#include "libc/nt/struct/ntexceptionpointers.h"
-#include "libc/nt/synchronization.h"
-#include "libc/nt/thread.h"
-#include "libc/runtime/internal.h"
-#include "libc/runtime/symbols.internal.h"
-#include "libc/str/str.h"
-#include "libc/sysv/consts/sa.h"
-#include "libc/sysv/consts/sicode.h"
-#include "libc/sysv/consts/ss.h"
-#include "libc/thread/posixthread.internal.h"
-#ifdef __x86_64__
-
-/**
- * @fileoverview Cosmopolitan Signals for Windows.
- */
-
-#define STKSZ 65536
-
-struct SignalFrame {
-  unsigned rva;
-  unsigned flags;
-  siginfo_t si;
-  ucontext_t ctx;
-};
-
-static textwindows bool __sig_ignored_by_default(int sig) {
-  return sig == SIGURG ||   //
-         sig == SIGCONT ||  //
-         sig == SIGCHLD ||  //
-         sig == SIGWINCH;
-}
-
-textwindows bool __sig_ignored(int sig) {
-  return __sighandrvas[sig] == (intptr_t)SIG_IGN ||
-         (__sighandrvas[sig] == (intptr_t)SIG_DFL &&
-          __sig_ignored_by_default(sig));
-}
-
-textwindows void __sig_delete(int sig) {
-  struct Dll *e;
-  atomic_fetch_and_explicit(__sig.process, ~(1ull << (sig - 1)),
-                            memory_order_relaxed);
-  _pthread_lock();
-  for (e = dll_last(_pthread_list); e; e = dll_prev(_pthread_list, e))
-    atomic_fetch_and_explicit(&POSIXTHREAD_CONTAINER(e)->tib->tib_sigpending,
-                              ~(1ull << (sig - 1)), memory_order_relaxed);
-  _pthread_unlock();
-}
-
-static textwindows int __sig_getter(atomic_ulong *sigs, sigset_t masked) {
-  int sig;
-  sigset_t bit, pending, deliverable;
-  for (;;) {
-    pending = atomic_load_explicit(sigs, memory_order_acquire);
-    if ((deliverable = pending & ~masked)) {
-      sig = bsfl(deliverable) + 1;
-      bit = 1ull << (sig - 1);
-      if (atomic_fetch_and_explicit(sigs, ~bit, memory_order_acq_rel) & bit)
-        return sig;
-    } else {
-      return 0;
-    }
-  }
-}
-
-textwindows int __sig_get(sigset_t masked) {
-  int sig;
-  if (!(sig = __sig_getter(&__get_tls()->tib_sigpending, masked)))
-    sig = __sig_getter(__sig.process, masked);
-  return sig;
-}
-
-static textwindows bool __sig_should_use_altstack(unsigned flags,
-                                                  struct CosmoTib *tib) {
-  if (!(flags & SA_ONSTACK))
-    return false;  // signal handler didn't enable it
-  if (!tib->tib_sigstack_size)
-    return false;  // sigaltstack() wasn't installed on this thread
-  if (tib->tib_sigstack_flags & SS_DISABLE)
-    return false;  // sigaltstack() on this thread was disabled by user
-  char *bp = __builtin_frame_address(0);
-  if (tib->tib_sigstack_addr <= bp &&
-      bp <= tib->tib_sigstack_addr + tib->tib_sigstack_size)
-    return false;  // we're already on the alternate stack
-  return true;
-}
-
-static textwindows wontreturn void __sig_terminate(int sig) {
-  TerminateThisProcess(sig);
-}
-
-textwindows static bool __sig_wake(struct PosixThread *pt, int sig) {
-  atomic_int *blocker;
-  blocker = atomic_load_explicit(&pt->pt_blocker, memory_order_acquire);
-  if (!blocker)
-    return false;
-  // threads can create semaphores on an as-needed basis
-  if (blocker == PT_BLOCKER_EVENT) {
-    STRACE("%G set %d's event object", sig, _pthread_tid(pt));
-    SetEvent(pt->pt_event);
-    return !!atomic_load_explicit(&pt->pt_blocker, memory_order_acquire);
-  }
-  // all other blocking ops that aren't overlap should use futexes
-  // we force restartable futexes to churn by waking w/o releasing
-  STRACE("%G waking %d's futex", sig, _pthread_tid(pt));
-  WakeByAddressSingle(blocker);
-  return !!atomic_load_explicit(&pt->pt_blocker, memory_order_acquire);
-}
-
-textwindows static bool __sig_start(struct PosixThread *pt, int sig,
-                                    unsigned *rva, unsigned *flags) {
-  *rva = __sighandrvas[sig];
-  *flags = __sighandflags[sig];
-  if (*rva == (intptr_t)SIG_IGN ||
-      (*rva == (intptr_t)SIG_DFL && __sig_ignored_by_default(sig))) {
-    STRACE("ignoring %G", sig);
-    return false;
-  }
-  if (atomic_load_explicit(&pt->tib->tib_sigmask, memory_order_acquire) &
-      (1ull << (sig - 1))) {
-    STRACE("enqueing %G on %d", sig, _pthread_tid(pt));
-    atomic_fetch_or_explicit(&pt->tib->tib_sigpending, 1ull << (sig - 1),
-                             memory_order_relaxed);
-    __sig_wake(pt, sig);
-    return false;
-  }
-  if (*rva == (intptr_t)SIG_DFL) {
-    STRACE("terminating on %G due to no handler", sig);
-    __sig_terminate(sig);
-  }
-  return true;
-}
-
-textwindows static sigaction_f __sig_handler(unsigned rva) {
-  atomic_fetch_add_explicit(&__sig.count, 1, memory_order_relaxed);
-  return (sigaction_f)(__executable_start + rva);
-}
-
-textwindows int __sig_raise(volatile int sig, int sic) {
-
-  // bitset of kinds of handlers called
-  volatile int handler_was_called = 0;
-
-  // loop over pending signals
-  ucontext_t ctx;
-  getcontext(&ctx);
-  if (!sig) {
-    if ((sig = __sig_get(ctx.uc_sigmask))) {
-      sic = SI_KERNEL;
-    } else {
-      return handler_was_called;
-    }
-  }
-
-  // process signal(s)
-  unsigned rva, flags;
-  struct PosixThread *pt = _pthread_self();
-  if (__sig_start(pt, sig, &rva, &flags)) {
-
-    if (flags & SA_RESETHAND) {
-      STRACE("resetting %G handler", sig);
-      __sighandrvas[sig] = (int32_t)(intptr_t)SIG_DFL;
-    }
-
-    // update the signal mask in preparation for signal handller
-    sigset_t blocksigs = __sighandmask[sig];
-    if (!(flags & SA_NODEFER))
-      blocksigs |= 1ull << (sig - 1);
-    ctx.uc_sigmask = atomic_fetch_or_explicit(&pt->tib->tib_sigmask, blocksigs,
-                                              memory_order_acquire);
-
-    // call the user's signal handler
-    char ssbuf[128];
-    siginfo_t si = {.si_signo = sig, .si_code = sic};
-    STRACE("__sig_raise(%G, %t) mask %s", sig, __sig_handler(rva),
-           _DescribeSigset(ssbuf, 0, (sigset_t *)&pt->tib->tib_sigmask));
-    __sig_handler(rva)(sig, &si, &ctx);
-
-    // record this handler
-    if (flags & SA_RESTART) {
-      handler_was_called |= SIG_HANDLED_SA_RESTART;
-    } else {
-      handler_was_called |= SIG_HANDLED_NO_RESTART;
-    }
-  }
-
-  // restore sigmask
-  // loop back to top
-  // jump where handler says
-  sig = 0;
-  return setcontext(&ctx);
-}
-
-textwindows int __sig_relay(int sig, int sic, sigset_t waitmask) {
-  sigset_t m;
-  int handler_was_called;
-  m = atomic_exchange_explicit(&__get_tls()->tib_sigmask, waitmask,
-                               memory_order_acquire);
-  handler_was_called = __sig_raise(sig, SI_KERNEL);
-  atomic_store_explicit(&__get_tls()->tib_sigmask, m, memory_order_release);
-  return handler_was_called;
-}
-
-// the user's signal handler callback is wrapped with this trampoline
-static textwindows wontreturn void __sig_tramp(struct SignalFrame *sf) {
-  int sig = sf->si.si_signo;
-  struct CosmoTib *tib = __get_tls();
-  struct PosixThread *pt = (struct PosixThread *)tib->tib_pthread;
-  atomic_store_explicit(&pt->pt_intoff, 0, memory_order_release);
-  for (;;) {
-
-    // update the signal mask in preparation for signal handler
-    sigset_t blocksigs = __sighandmask[sig];
-    if (!(sf->flags & SA_NODEFER))
-      blocksigs |= 1ull << (sig - 1);
-    sf->ctx.uc_sigmask = atomic_fetch_or_explicit(&tib->tib_sigmask, blocksigs,
-                                                  memory_order_acquire);
-
-    // call the user's signal handler
-    char ssbuf[2][128];
-    STRACE("__sig_tramp(%G, %t) mask %s → %s", sig, __sig_handler(sf->rva),
-           _DescribeSigset(ssbuf[0], 0, &sf->ctx.uc_sigmask),
-           _DescribeSigset(ssbuf[1], 0, (sigset_t *)&tib->tib_sigmask));
-    __sig_handler(sf->rva)(sig, &sf->si, &sf->ctx);
-
-    // restore the signal mask that was used by the interrupted code
-    // this may have been modified by the signal handler in the callback
-    atomic_store_explicit(&tib->tib_sigmask, sf->ctx.uc_sigmask,
-                          memory_order_release);
-
-    // jump back into original code if there aren't any pending signals
-    do {
-      if (!(sig = __sig_get(sf->ctx.uc_sigmask)))
-        __sig_restore(&sf->ctx);
-    } while (!__sig_start(pt, sig, &sf->rva, &sf->flags));
-
-    // tail recurse into another signal handler
-    sf->si.si_signo = sig;
-    sf->si.si_code = SI_KERNEL;
-    if (sf->flags & SA_RESETHAND) {
-      STRACE("resetting %G handler", sig);
-      __sighandrvas[sig] = (int32_t)(intptr_t)SIG_DFL;
-    }
-  }
-}
-
-// sends signal to another specific thread which is ref'd
-static textwindows int __sig_killer(struct PosixThread *pt, int sig, int sic) {
-  unsigned rva = __sighandrvas[sig];
-  unsigned flags = __sighandflags[sig];
-
-  // do nothing if signal is ignored
-  if (rva == (intptr_t)SIG_IGN ||
-      (rva == (intptr_t)SIG_DFL && __sig_ignored_by_default(sig))) {
-    STRACE("ignoring %G", sig);
-    return 0;
-  }
-
-  // we can't preempt threads that masked sigs or are blocked on i/o
-  while ((atomic_load_explicit(&pt->tib->tib_sigmask, memory_order_acquire) &
-          (1ull << (sig - 1)))) {
-    if (atomic_fetch_or_explicit(&pt->tib->tib_sigpending, 1ull << (sig - 1),
-                                 memory_order_acq_rel) &
-        (1ull << (sig - 1)))
-      // we believe signal was already enqueued
-      return 0;
-    if (__sig_wake(pt, sig))
-      // we believe i/o routine will handle signal
-      return 0;
-    if (atomic_load_explicit(&pt->tib->tib_sigmask, memory_order_acquire) &
-        (1ull << (sig - 1)))
-      // we believe ALLOW_SIGNALS will handle signal
-      return 0;
-    if (!(atomic_fetch_and_explicit(&pt->tib->tib_sigpending,
-                                    ~(1ull << (sig - 1)),
-                                    memory_order_acq_rel) &
-          (1ull << (sig - 1))))
-      // we believe another thread sniped our signal
-      return 0;
-    break;
-  }
-
-  // avoid race conditions and deadlocks with thread suspend process
-  if (atomic_exchange_explicit(&pt->pt_intoff, 1, memory_order_acquire)) {
-    // we believe another thread is asynchronously waking the mark
-    if (atomic_fetch_or_explicit(&pt->tib->tib_sigpending, 1ull << (sig - 1),
-                                 memory_order_acq_rel) &
-        (1ull << (sig - 1)))
-      // we believe our signal is already being delivered
-      return 0;
-    if (atomic_load_explicit(&pt->pt_intoff, memory_order_acquire) ||
-        atomic_exchange_explicit(&pt->pt_intoff, 1, memory_order_acquire))
-      // we believe __sig_tramp will deliver our signal
-      return 0;
-    if (!(atomic_fetch_and_explicit(&pt->tib->tib_sigpending,
-                                    ~(1ull << (sig - 1)),
-                                    memory_order_acq_rel) &
-          (1ull << (sig - 1))))
-      // we believe another thread sniped our signal
-      return 0;
-  }
-
-  // if there's no handler then killing a thread kills the process
-  if (rva == (intptr_t)SIG_DFL) {
-    STRACE("terminating on %G due to no handler", sig);
-    __sig_terminate(sig);
-  }
-
-  // take control of thread
-  // suspending the thread happens asynchronously
-  // however getting the context blocks until it's frozen
-  uintptr_t th = _pthread_syshand(pt);
-  if (SuspendThread(th) == -1u) {
-    STRACE("SuspendThread failed w/ %d", GetLastError());
-    atomic_store_explicit(&pt->pt_intoff, 0, memory_order_release);
-    return ESRCH;
-  }
-  struct NtContext nc;
-  nc.ContextFlags = kNtContextFull;
-  if (!GetThreadContext(th, &nc)) {
-    STRACE("GetThreadContext failed w/ %d", GetLastError());
-    ResumeThread(th);
-    atomic_store_explicit(&pt->pt_intoff, 0, memory_order_release);
-    return ESRCH;
-  }
-
-  // we can't preempt threads that masked sig or are blocked
-  // we can't preempt threads that are running in win32 code
-  // so we shall unblock the thread and let it signal itself
-  if (!((uintptr_t)__executable_start <= nc.Rip &&
-        nc.Rip < (uintptr_t)__privileged_start)) {
-    atomic_fetch_or_explicit(&pt->tib->tib_sigpending, 1ull << (sig - 1),
-                             memory_order_relaxed);
-    ResumeThread(th);
-    atomic_store_explicit(&pt->pt_intoff, 0, memory_order_release);
-    __sig_wake(pt, sig);
-    return 0;
-  }
-
-  // preferring to live dangerously
-  // the thread will be signaled asynchronously
-  if (flags & SA_RESETHAND) {
-    STRACE("resetting %G handler", sig);
-    __sighandrvas[sig] = (int32_t)(intptr_t)SIG_DFL;
-  }
-
-  // inject call to trampoline function into thread
-  uintptr_t sp;
-  if (__sig_should_use_altstack(flags, pt->tib)) {
-    sp = (uintptr_t)pt->tib->tib_sigstack_addr + pt->tib->tib_sigstack_size;
-  } else {
-    sp = nc.Rsp;
-  }
-  sp -= sizeof(struct SignalFrame);
-  sp &= -16;
-  struct SignalFrame *sf = (struct SignalFrame *)sp;
-  _ntcontext2linux(&sf->ctx, &nc);
-  bzero(&sf->si, sizeof(sf->si));
-  sf->rva = rva;
-  sf->flags = flags;
-  sf->si.si_code = sic;
-  sf->si.si_signo = sig;
-  *(uintptr_t *)(sp -= sizeof(uintptr_t)) = nc.Rip;
-  nc.Rip = (intptr_t)__sig_tramp;
-  nc.Rdi = (intptr_t)sf;
-  nc.Rsp = sp;
-  if (!SetThreadContext(th, &nc)) {
-    STRACE("SetThreadContext failed w/ %d", GetLastError());
-    atomic_store_explicit(&pt->pt_intoff, 0, memory_order_release);
-    return ESRCH;
-  }
-  ResumeThread(th);
-  __sig_wake(pt, sig);
-  return 0;
-}
-
-// sends signal to another specific thread
-textwindows int __sig_kill(struct PosixThread *pt, int sig, int sic) {
-  int rc;
-  BLOCK_SIGNALS;
-  rc = __sig_killer(pt, sig, sic);
-  ALLOW_SIGNALS;
-  return rc;
-}
-
-// sends signal to any other thread
-// this should only be called by non-posix threads
-textwindows void __sig_generate(int sig, int sic) {
-  struct Dll *e;
-  struct PosixThread *pt, *mark = 0;
-  if (__sig_ignored(sig)) {
-    STRACE("ignoring %G", sig);
-    return;
-  }
-  if (__sighandrvas[sig] == (intptr_t)SIG_DFL) {
-    STRACE("terminating on %G due to no handler", sig);
-    __sig_terminate(sig);
-  }
-  if (atomic_load_explicit(__sig.process, memory_order_acquire) &
-      (1ull << (sig - 1))) {
-    return;
-  }
-  _pthread_lock();
-  for (e = dll_first(_pthread_list); e; e = dll_next(_pthread_list, e)) {
-    pt = POSIXTHREAD_CONTAINER(e);
-    // we don't want to signal ourself
-    if (pt == _pthread_self())
-      continue;
-    // we don't want to signal a thread that isn't running
-    if (atomic_load_explicit(&pt->pt_status, memory_order_acquire) >=
-        kPosixThreadTerminated) {
-      continue;
-    }
-    // choose this thread if it isn't masking sig
-    if (!(atomic_load_explicit(&pt->tib->tib_sigmask, memory_order_acquire) &
-          (1ull << (sig - 1)))) {
-      _pthread_ref(pt);
-      mark = pt;
-      break;
-    }
-    // if a thread is blocking then we check to see if it's planning
-    // to unblock our sig once the wait operation is completed; when
-    // that's the case we can cancel the thread's i/o to deliver sig
-    if (atomic_load_explicit(&pt->pt_blocker, memory_order_acquire) &&
-        !(pt->pt_blkmask & (1ull << (sig - 1)))) {
-      _pthread_ref(pt);
-      mark = pt;
-      break;
-    }
-  }
-  _pthread_unlock();
-  if (mark) {
-    // no lock needed since current thread is nameless and formless
-    __sig_killer(mark, sig, sic);
-    _pthread_unref(mark);
-  } else {
-    atomic_fetch_or_explicit(__sig.process, 1ull << (sig - 1),
-                             memory_order_relaxed);
-  }
-}
-
-static textwindows char *__sig_stpcpy(char *d, const char *s) {
-  size_t i;
-  for (i = 0;; ++i)
-    if (!(d[i] = s[i]))
-      return d + i;
-}
-
-static textwindows wontreturn void __sig_death(int sig, const char *thing) {
-#ifndef TINY
-  intptr_t hStderr;
-  char sigbuf[21], s[128], *p;
-  hStderr = GetStdHandle(kNtStdErrorHandle);
-  p = __sig_stpcpy(s, "Terminating on ");
-  p = __sig_stpcpy(p, thing);
-  p = __sig_stpcpy(p, strsignal_r(sig, sigbuf));
-  p = __sig_stpcpy(p,
-                   ". Pass --strace and/or ShowCrashReports() for details.\n");
-  WriteFile(hStderr, s, p - s, 0, 0);
-#endif
-  __sig_terminate(sig);
-}
-
-static textwindows void __sig_unmaskable(struct NtExceptionPointers *ep,
-                                         int code, int sig,
-                                         struct CosmoTib *tib) {
-
-  // log vital crash information reliably for --strace before doing much
-  // we don't print this without the flag since raw numbers scare people
-  // this needs at least one page of stack memory in order to get logged
-  // otherwise it'll print a warning message about the lack of stack mem
-  STRACE("win32 vectored exception 0x%08Xu raising %G "
-         "cosmoaddr2line %s %lx %s",
-         ep->ExceptionRecord->ExceptionCode, sig,
-         _weaken(FindDebugBinary) ? _weaken(FindDebugBinary)()
-                                  : program_invocation_name,
-         ep->ContextRecord->Rip,
-         DescribeBacktrace((struct StackFrame *)ep->ContextRecord->Rbp));
-
-  // if the user didn't install a signal handler for this unmaskable
-  // exception, then print a friendly helpful hint message to stderr
-  unsigned rva = __sighandrvas[sig];
-  if (rva == (intptr_t)SIG_DFL || rva == (intptr_t)SIG_IGN)
-    __sig_death(sig, "uncaught ");
-
-  // if this signal handler is configured to auto-reset to the default
-  // then that reset needs to happen before the user handler is called
-  unsigned flags = __sighandflags[sig];
-  if (flags & SA_RESETHAND) {
-    STRACE("resetting %G handler", sig);
-    __sighandrvas[sig] = (int32_t)(intptr_t)SIG_DFL;
-  }
-
-  // determine the true memory address at which fault occurred
-  // if this is a stack overflow then reapply guard protection
-  void *si_addr;
-  if (ep->ExceptionRecord->ExceptionCode == kNtSignalGuardPage) {
-    si_addr = (void *)ep->ExceptionRecord->ExceptionInformation[1];
-  } else {
-    si_addr = ep->ExceptionRecord->ExceptionAddress;
-  }
-
-  // call the user signal handler
-  // and a modifiable view of the faulting code's cpu state
-  // temporarily replace signal mask while calling crash handler
-  // abort process if sig is already blocked to avoid crash loop
-  // note ucontext_t is a hefty data structures on top of NtContext
-  ucontext_t ctx = {0};
-  siginfo_t si = {.si_signo = sig, .si_code = code, .si_addr = si_addr};
-  _ntcontext2linux(&ctx, ep->ContextRecord);
-  sigset_t blocksigs = __sighandmask[sig];
-  if (!(flags & SA_NODEFER))
-    blocksigs |= 1ull << (sig - 1);
-  ctx.uc_sigmask = atomic_fetch_or_explicit(&tib->tib_sigmask, blocksigs,
-                                            memory_order_acquire);
-  if (ctx.uc_sigmask & (1ull << (sig - 1))) {
-    __sig_death(sig, "masked ");
-    __sig_terminate(sig);
-  }
-  __sig_handler(rva)(sig, &si, &ctx);
-  atomic_store_explicit(&tib->tib_sigmask, ctx.uc_sigmask,
-                        memory_order_release);
-  _ntlinux2context(ep->ContextRecord, &ctx);
-}
-
-void __stack_call(struct NtExceptionPointers *, int, int, struct CosmoTib *,
-                  void (*)(struct NtExceptionPointers *, int, int,
-                           struct CosmoTib *),
-                  void *);
-
-//                         abashed the devil stood
-//                      and felt how awful goodness is
-__msabi dontinstrument unsigned __sig_crash(struct NtExceptionPointers *ep) {
-
-  // translate win32 to unix si_signo and si_code
-  int code, sig = __sig_crash_sig(ep->ExceptionRecord->ExceptionCode, &code);
-
-  // advance the instruction pointer to skip over debugger breakpoints
-  // this behavior is consistent with how unix kernels are implemented
-  if (sig == SIGTRAP) {
-    ep->ContextRecord->Rip++;
-    if (__sig_ignored(sig))
-      return kNtExceptionContinueExecution;
-  }
-
-  // win32 stack overflow detection executes INSIDE the guard page
-  // thus switch to the alternate signal stack as soon as possible
-  struct CosmoTib *tib = __get_tls();
-  unsigned flags = __sighandflags[sig];
-  if (__sig_should_use_altstack(flags, tib)) {
-    __stack_call(ep, code, sig, tib, __sig_unmaskable,
-                 tib->tib_sigstack_addr + tib->tib_sigstack_size);
-  } else {
-    __sig_unmaskable(ep, code, sig, tib);
-  }
-
-  // resume running user program
-  // hopefully the user fixed the cpu state
-  // otherwise the crash will keep happening
-  return kNtExceptionContinueExecution;
-}
-
-static textwindows int __sig_console_sig(uint32_t dwCtrlType) {
-  switch (dwCtrlType) {
-    case kNtCtrlCEvent:
-      return SIGINT;
-    case kNtCtrlBreakEvent:
-      return SIGQUIT;
-    case kNtCtrlCloseEvent:
-    case kNtCtrlLogoffEvent:    // only received by services
-    case kNtCtrlShutdownEvent:  // only received by services
-      return SIGHUP;
-    default:
-      return SIGSTKFLT;
-  }
-}
-
-__msabi textwindows dontinstrument bool32 __sig_console(uint32_t dwCtrlType) {
-  // win32 launches a thread to deliver ctrl-c and ctrl-break when typed
-  // it only happens when kNtEnableProcessedInput is in play on console.
-  // otherwise we need to wait until read-nt.c discovers that keystroke.
-  struct CosmoTib tls;
-  __bootstrap_tls(&tls, __builtin_frame_address(0));
-  __sig_generate(__sig_console_sig(dwCtrlType), SI_KERNEL);
-  return true;
-}
-
-// returns 0 if no signal handlers were called, otherwise a bitmask
-// consisting of `1` which means a signal handler was invoked which
-// didn't have the SA_RESTART flag, and `2`, which means SA_RESTART
-// handlers were called (or `3` if both were the case).
-textwindows int __sig_check(void) {
-  int sig, res = 0;
-  while ((sig = __sig_get(atomic_load_explicit(&__get_tls()->tib_sigmask,
-                                               memory_order_acquire))))
-    res |= __sig_raise(sig, SI_KERNEL);
-  return res;
-}
-
-// background thread for delivering inter-process signals asynchronously
-// this checks for undelivered process-wide signals, once per scheduling
-// quantum, which on windows should be every ~15ms or so, unless somehow
-// the process was tuned to have more fine-grained event timing. we want
-// signals to happen faster when possible; that happens when cancelation
-// points, e.g. read need to wait on i/o; they too check for new signals
-textwindows dontinstrument static uint32_t __sig_worker(void *arg) {
-  struct CosmoTib tls;
-  __bootstrap_tls(&tls, __builtin_frame_address(0));
-  char *sp = __builtin_frame_address(0);
-  __maps_track((char *)(((uintptr_t)sp + __pagesize - 1) & -__pagesize) - STKSZ,
-               STKSZ);
-  for (;;) {
-
-    // dequeue all pending signals and fire them off. if there's no
-    // thread that can handle them then __sig_generate will requeue
-    // those signals back to __sig.process; hence the need for xchg
-    unsigned long sigs =
-        atomic_exchange_explicit(__sig.process, 0, memory_order_acq_rel);
-    while (sigs) {
-      int sig = bsfl(sigs) + 1;
-      sigs &= ~(1ull << (sig - 1));
-      __sig_generate(sig, SI_KERNEL);
-    }
-
-    // unblock stalled asynchronous signals in threads
-    _pthread_lock();
-    for (struct Dll *e = dll_first(_pthread_list); e;
-         e = dll_next(_pthread_list, e)) {
-      struct PosixThread *pt = POSIXTHREAD_CONTAINER(e);
-      if (atomic_load_explicit(&pt->pt_status, memory_order_acquire) >=
-          kPosixThreadTerminated) {
-        break;
-      }
-      sigset_t pending =
-          atomic_load_explicit(&pt->tib->tib_sigpending, memory_order_acquire);
-      sigset_t mask =
-          atomic_load_explicit(&pt->tib->tib_sigmask, memory_order_acquire);
-      if (pending & ~mask) {
-        _pthread_ref(pt);
-        _pthread_unlock();
-        while (!atomic_compare_exchange_weak_explicit(
-            &pt->tib->tib_sigpending, &pending, pending & ~mask,
-            memory_order_acq_rel, memory_order_relaxed)) {
-        }
-        while ((pending = pending & ~mask)) {
-          int sig = bsfl(pending) + 1;
-          pending &= ~(1ull << (sig - 1));
-          __sig_killer(pt, sig, SI_KERNEL);
-        }
-        _pthread_lock();
-        _pthread_unref(pt);
-      }
-    }
-    _pthread_unlock();
-
-    // wait until next scheduler quantum
-    Sleep(POLL_INTERVAL_MS);
-  }
-  return 0;
-}
-
-__attribute__((__constructor__(10))) textstartup void __sig_init(void) {
-  if (!IsWindows())
-    return;
-  AddVectoredExceptionHandler(true, (void *)__sig_crash);
-  SetConsoleCtrlHandler((void *)__sig_console, true);
-  CreateThread(0, STKSZ, __sig_worker, 0, kNtStackSizeParamIsAReservation, 0);
-}
-
-#endif /* __x86_64__ */
diff --git a/libc/cosmo.h b/libc/cosmo.h
index 4111b132a..21b1de175 100644
--- a/libc/cosmo.h
+++ b/libc/cosmo.h
@@ -1,5 +1,6 @@
 #ifndef COSMOPOLITAN_LIBC_COSMO_H_
 #define COSMOPOLITAN_LIBC_COSMO_H_
+#include "libc/calls/struct/timespec.h"
 COSMOPOLITAN_C_START_
 
 #ifndef __cplusplus
@@ -17,6 +18,9 @@ int __is_mangled(const char *) libcesque;
 bool32 IsLinuxModern(void) libcesque;
 int LoadZipArgs(int *, char ***) libcesque;
 int cosmo_args(const char *, char ***) libcesque;
+int cosmo_futex_wake(_COSMO_ATOMIC(int) *, int, char);
+int cosmo_futex_wait(_COSMO_ATOMIC(int) *, int, char, int,
+                     const struct timespec *);
 
 COSMOPOLITAN_C_END_
 #endif /* COSMOPOLITAN_LIBC_COSMO_H_ */
diff --git a/libc/intrin/BUILD.mk b/libc/intrin/BUILD.mk
index abe5b17b9..dfef72d12 100644
--- a/libc/intrin/BUILD.mk
+++ b/libc/intrin/BUILD.mk
@@ -30,9 +30,11 @@ LIBC_INTRIN_A_CHECKS =					\
 LIBC_INTRIN_A_DIRECTDEPS =				\
 	LIBC_NEXGEN32E					\
 	LIBC_NT_KERNEL32				\
+	LIBC_NT_REALTIME				\
+	LIBC_NT_SYNCHRONIZATION				\
 	LIBC_NT_WS2_32					\
 	LIBC_SYSV					\
-	LIBC_SYSV_CALLS
+	LIBC_SYSV_CALLS					\
 
 LIBC_INTRIN_A_DEPS :=					\
 	$(call uniq,$(foreach x,$(LIBC_INTRIN_A_DIRECTDEPS),$($(x))))
@@ -106,6 +108,16 @@ o//libc/intrin/demangle.o: private			\
 		CFLAGS +=				\
 			-mgeneral-regs-only
 
+# ensure that division is optimized
+o/$(MODE)/libc/intrin/windowsdurationtotimeval.o	\
+o/$(MODE)/libc/intrin/windowsdurationtotimespec.o	\
+o/$(MODE)/libc/intrin/timevaltowindowstime.o		\
+o/$(MODE)/libc/intrin/timespectowindowstime.o		\
+o/$(MODE)/libc/intrin/windowstimetotimeval.o		\
+o/$(MODE)/libc/intrin/windowstimetotimespec.o: private	\
+		CFLAGS +=				\
+			-O2
+
 # these assembly files are safe to build on aarch64
 o/$(MODE)/libc/intrin/aarch64/%.o: libc/intrin/aarch64/%.S
 	@$(COMPILE) -AOBJECTIFY.S $(OBJECTIFY.S) $(OUTPUT_OPTION) -c $<
diff --git a/libc/calls/checkcancel.c b/libc/intrin/checkcancel.c
similarity index 100%
rename from libc/calls/checkcancel.c
rename to libc/intrin/checkcancel.c
diff --git a/libc/calls/clock_gettime-mono.c b/libc/intrin/clock_gettime-mono.c
similarity index 100%
rename from libc/calls/clock_gettime-mono.c
rename to libc/intrin/clock_gettime-mono.c
diff --git a/libc/calls/clock_gettime-nt.c b/libc/intrin/clock_gettime-nt.c
similarity index 100%
rename from libc/calls/clock_gettime-nt.c
rename to libc/intrin/clock_gettime-nt.c
diff --git a/libc/calls/clock_gettime-sysv.c b/libc/intrin/clock_gettime-sysv.c
similarity index 100%
rename from libc/calls/clock_gettime-sysv.c
rename to libc/intrin/clock_gettime-sysv.c
diff --git a/libc/calls/clock_gettime-xnu.c b/libc/intrin/clock_gettime-xnu.c
similarity index 100%
rename from libc/calls/clock_gettime-xnu.c
rename to libc/intrin/clock_gettime-xnu.c
diff --git a/libc/calls/clock_gettime.c b/libc/intrin/clock_gettime.c
similarity index 100%
rename from libc/calls/clock_gettime.c
rename to libc/intrin/clock_gettime.c
diff --git a/libc/calls/clock_gettime_monotonic_nt.c b/libc/intrin/clock_gettime_monotonic_nt.c
similarity index 100%
rename from libc/calls/clock_gettime_monotonic_nt.c
rename to libc/intrin/clock_gettime_monotonic_nt.c
diff --git a/third_party/nsync/futex.c b/libc/intrin/cosmo_futex.c
similarity index 72%
rename from third_party/nsync/futex.c
rename to libc/intrin/cosmo_futex.c
index b7662a544..ee1e14b38 100644
--- a/third_party/nsync/futex.c
+++ b/libc/intrin/cosmo_futex.c
@@ -16,18 +16,14 @@
 │ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
-#include "libc/sysv/consts/futex.h"
 #include "libc/assert.h"
 #include "libc/atomic.h"
-#include "libc/calls/calls.h"
 #include "libc/calls/internal.h"
 #include "libc/calls/sig.internal.h"
-#include "libc/calls/state.internal.h"
 #include "libc/calls/struct/sigset.h"
 #include "libc/calls/struct/sigset.internal.h"
 #include "libc/calls/struct/timespec.h"
 #include "libc/calls/struct/timespec.internal.h"
-#include "libc/calls/syscall_support-nt.internal.h"
 #include "libc/cosmo.h"
 #include "libc/dce.h"
 #include "libc/errno.h"
@@ -37,62 +33,56 @@
 #include "libc/intrin/ulock.h"
 #include "libc/intrin/weaken.h"
 #include "libc/limits.h"
-#include "libc/nexgen32e/vendor.internal.h"
 #include "libc/nt/runtime.h"
 #include "libc/nt/synchronization.h"
-#include "libc/runtime/clktck.h"
+#include "libc/sysv/consts/clock.h"
+#include "libc/sysv/consts/futex.h"
 #include "libc/sysv/consts/sicode.h"
-#include "libc/sysv/consts/timer.h"
 #include "libc/sysv/errfuns.h"
 #include "libc/thread/freebsd.internal.h"
 #include "libc/thread/posixthread.internal.h"
 #include "libc/thread/thread.h"
-#include "libc/thread/tls.h"
-#include "third_party/nsync/atomic.h"
-#include "third_party/nsync/time.h"
-#include "third_party/nsync/common.internal.h"
-#include "third_party/nsync/futex.internal.h"
-#include "third_party/nsync/time.h"
+// clang-format off
 
 #define FUTEX_WAIT_BITS_ FUTEX_BITSET_MATCH_ANY
 
-errno_t _futex (atomic_int *, int, int, const struct timespec *, int *, int);
-errno_t _futex_wake (atomic_int *, int, int) asm ("_futex");
+errno_t cosmo_futex_thunk (atomic_int *, int, int, const struct timespec *, int *, int);
+errno_t _futex_wake (atomic_int *, int, int) asm ("cosmo_futex_thunk");
 int sys_futex_cp (atomic_int *, int, int, const struct timespec *, int *, int);
 
-static struct NsyncFutex {
+static struct CosmoFutex {
 	atomic_uint once;
 	int FUTEX_WAIT_;
 	int FUTEX_PRIVATE_FLAG_;
 	int FUTEX_CLOCK_REALTIME_;
 	bool is_supported;
 	bool timeout_is_relative;
-} nsync_futex_;
+} g_cosmo_futex;
 
-static void nsync_futex_init_ (void) {
+static void cosmo_futex_init (void) {
 	int e;
 	atomic_int x;
 
-	nsync_futex_.FUTEX_WAIT_ = FUTEX_WAIT;
+	g_cosmo_futex.FUTEX_WAIT_ = FUTEX_WAIT;
 
 	if (IsWindows ()) {
-		nsync_futex_.is_supported = true;
+		g_cosmo_futex.is_supported = true;
 		return;
 	}
 
 	if (IsXnu ()) {
-		nsync_futex_.is_supported = true;
-		nsync_futex_.timeout_is_relative = true;
+		g_cosmo_futex.is_supported = true;
+		g_cosmo_futex.timeout_is_relative = true;
 		return;
 	}
 
 	if (IsFreebsd ()) {
-		nsync_futex_.is_supported = true;
-		nsync_futex_.FUTEX_PRIVATE_FLAG_ = FUTEX_PRIVATE_FLAG;
+		g_cosmo_futex.is_supported = true;
+		g_cosmo_futex.FUTEX_PRIVATE_FLAG_ = FUTEX_PRIVATE_FLAG;
 		return;
 	}
 
-	if (!(nsync_futex_.is_supported = IsLinux () || IsOpenbsd ()))
+	if (!(g_cosmo_futex.is_supported = IsLinux () || IsOpenbsd ()))
 		return;
 
 	// In our testing, we found that the monotonic clock on various
@@ -100,7 +90,7 @@ static void nsync_futex_init_ (void) {
 	// better behaved than the realtime clock, and routinely took
 	// large steps backwards, especially on multiprocessors. Given
 	// that "monotonic" doesn't seem to mean what it says,
-	// implementers of nsync_time might consider retaining the
+	// implementers of cosmo_time might consider retaining the
 	// simplicity of a single epoch within an address space, by
 	// configuring any time synchronization mechanism (like ntp) to
 	// adjust for leap seconds by adjusting the rate, rather than
@@ -108,31 +98,32 @@ static void nsync_futex_init_ (void) {
 	e = errno;
 	atomic_store_explicit (&x, 0, memory_order_relaxed);
 	if (IsLinux () &&
-	    _futex (&x, FUTEX_WAIT_BITSET | FUTEX_CLOCK_REALTIME,
-		    1, 0, 0, FUTEX_BITSET_MATCH_ANY) == -EAGAIN) {
-		nsync_futex_.FUTEX_WAIT_ = FUTEX_WAIT_BITSET;
-		nsync_futex_.FUTEX_PRIVATE_FLAG_ = FUTEX_PRIVATE_FLAG;
-		nsync_futex_.FUTEX_CLOCK_REALTIME_ = FUTEX_CLOCK_REALTIME;
+	    cosmo_futex_thunk (&x, FUTEX_WAIT_BITSET | FUTEX_CLOCK_REALTIME,
+			       1, 0, 0, FUTEX_BITSET_MATCH_ANY) == -EAGAIN) {
+		g_cosmo_futex.FUTEX_WAIT_ = FUTEX_WAIT_BITSET;
+		g_cosmo_futex.FUTEX_PRIVATE_FLAG_ = FUTEX_PRIVATE_FLAG;
+		g_cosmo_futex.FUTEX_CLOCK_REALTIME_ = FUTEX_CLOCK_REALTIME;
 	} else if (IsOpenbsd () ||
 		   (IsLinux () &&
 		    !_futex_wake (&x, FUTEX_WAKE_PRIVATE, 1))) {
-		nsync_futex_.FUTEX_WAIT_ = FUTEX_WAIT;
-		nsync_futex_.FUTEX_PRIVATE_FLAG_ = FUTEX_PRIVATE_FLAG;
-		nsync_futex_.timeout_is_relative = true;
+		g_cosmo_futex.FUTEX_WAIT_ = FUTEX_WAIT;
+		g_cosmo_futex.FUTEX_PRIVATE_FLAG_ = FUTEX_PRIVATE_FLAG;
+		g_cosmo_futex.timeout_is_relative = true;
 	} else {
-		nsync_futex_.FUTEX_WAIT_ = FUTEX_WAIT;
-		nsync_futex_.timeout_is_relative = true;
+		g_cosmo_futex.FUTEX_WAIT_ = FUTEX_WAIT;
+		g_cosmo_futex.timeout_is_relative = true;
 	}
 	errno = e;
 }
 
-static uint32_t nsync_time_64to32u (uint64_t duration) {
+static uint32_t cosmo_time_64to32u (uint64_t duration) {
 	if (duration <= -1u)
 		return duration;
 	return -1u;
 }
 
-static int nsync_futex_polyfill_ (atomic_int *w, int expect, int clock, struct timespec *abstime) {
+static int cosmo_futex_polyfill (atomic_int *w, int expect, int clock,
+				 struct timespec *abstime) {
 	for (;;) {
 		if (atomic_load_explicit (w, memory_order_acquire) != expect)
 			return 0;
@@ -148,10 +139,10 @@ static int nsync_futex_polyfill_ (atomic_int *w, int expect, int clock, struct t
 	}
 }
 
-static int nsync_futex_wait_win32_ (atomic_int *w, int expect, char pshare,
-				    int clock, const struct timespec *timeout,
-				    struct PosixThread *pt,
-				    sigset_t waitmask) {
+static int cosmo_futex_wait_win32 (atomic_int *w, int expect, char pshare,
+				   int clock, const struct timespec *timeout,
+				   struct PosixThread *pt,
+				   sigset_t waitmask) {
 #ifdef __x86_64__
 	int sig;
 	bool32 ok;
@@ -183,7 +174,7 @@ static int nsync_futex_wait_win32_ (atomic_int *w, int expect, char pshare,
 			pt->pt_blkmask = waitmask;
 			atomic_store_explicit (&pt->pt_blocker, w, memory_order_release);
 		}
-		ok = WaitOnAddress (w, &expect, sizeof(int), nsync_time_64to32u (timespec_tomillis (wait)));
+		ok = WaitOnAddress (w, &expect, sizeof(int), cosmo_time_64to32u (timespec_tomillis (wait)));
 		if (pt) {
 			/* __sig_wake wakes our futex without changing `w` after enqueing signals */
 			atomic_store_explicit (&pt->pt_blocker, 0, memory_order_release);
@@ -197,7 +188,7 @@ static int nsync_futex_wait_win32_ (atomic_int *w, int expect, char pshare,
 		if (ok) {
 			return 0;
 		} else {
-			ASSERT (GetLastError () == ETIMEDOUT);
+			unassert (GetLastError () == ETIMEDOUT);
 		}
 	}
 #else
@@ -205,14 +196,14 @@ static int nsync_futex_wait_win32_ (atomic_int *w, int expect, char pshare,
 #endif /* __x86_64__ */
 }
 
-static int nsync_futex_fix_timeout_ (struct timespec *memory, int clock,
-				     const struct timespec *abstime,
-				     struct timespec **result) {
+static int cosmo_futex_fix_timeout (struct timespec *memory, int clock,
+				    const struct timespec *abstime,
+				    struct timespec **result) {
 	struct timespec now;
 	if (!abstime) {
 		*result = 0;
 		return 0;
-	} else if (!nsync_futex_.timeout_is_relative) {
+	} else if (!g_cosmo_futex.timeout_is_relative) {
 		*memory = *abstime;
 		*result = memory;
 		return 0;
@@ -225,22 +216,39 @@ static int nsync_futex_fix_timeout_ (struct timespec *memory, int clock,
 	}
 }
 
-int nsync_futex_wait_ (atomic_int *w, int expect, char pshare,
-		       int clock, const struct timespec *abstime) {
+/**
+ * Waits on futex.
+ *
+ * This function may be used to ask the OS to park the calling thread
+ * until cosmo_futex_wake() is called on the memory address `w`.
+ *
+ * @param w is your futex
+ * @param expect is the value `*w` is expected to have on entry
+ * @param pshare is `PTHREAD_PROCESS_PRIVATE` / `PTHREAD_PROCESS_SHARED`
+ * @param clock is `CLOCK_MONOTONIC`, `CLOCK_REALTIME`, etc.
+ * @param abstime is null to wait forever or absolute timestamp to stop
+ * @return 0 on success, or -errno on error
+ * @raise EINVAL on bad parameter
+ * @raise EAGAIN if `*w` wasn't `expect`
+ * @raise EINTR if a signal handler was called while waiting
+ * @raise ECANCELED if calling thread was canceled while waiting
+ */
+int cosmo_futex_wait (atomic_int *w, int expect, char pshare,
+		      int clock, const struct timespec *abstime) {
 	int e, rc, op;
 	struct CosmoTib *tib;
 	struct PosixThread *pt;
 	struct timespec tsmem;
 	struct timespec *timeout = 0;
 
-	cosmo_once (&nsync_futex_.once, nsync_futex_init_);
+	cosmo_once (&g_cosmo_futex.once, cosmo_futex_init);
 
-	op = nsync_futex_.FUTEX_WAIT_;
+	op = g_cosmo_futex.FUTEX_WAIT_;
 	if (pshare == PTHREAD_PROCESS_PRIVATE)
-		op |= nsync_futex_.FUTEX_PRIVATE_FLAG_;
+		op |= g_cosmo_futex.FUTEX_PRIVATE_FLAG_;
 	if (clock == CLOCK_REALTIME ||
 	    clock == CLOCK_REALTIME_COARSE)
-		op |= nsync_futex_.FUTEX_CLOCK_REALTIME_;
+		op |= g_cosmo_futex.FUTEX_CLOCK_REALTIME_;
 
 	if (abstime && timespec_cmp (*abstime, timespec_zero) <= 0) {
 		rc = -ETIMEDOUT;
@@ -252,7 +260,7 @@ int nsync_futex_wait_ (atomic_int *w, int expect, char pshare,
 		goto Finished;
 	}
 
-	if ((rc = nsync_futex_fix_timeout_ (&tsmem, clock, abstime, &timeout)))
+	if ((rc = cosmo_futex_fix_timeout (&tsmem, clock, abstime, &timeout)))
 		goto Finished;
 
 	LOCKTRACE ("futex(%t [%d], %s, %#x, %s) → ...",
@@ -263,13 +271,13 @@ int nsync_futex_wait_ (atomic_int *w, int expect, char pshare,
 	tib = __get_tls();
 	pt = (struct PosixThread *)tib->tib_pthread;
 
-	if (nsync_futex_.is_supported) {
+	if (g_cosmo_futex.is_supported) {
 		e = errno;
 		if (IsWindows ()) {
 			// Windows 8 futexes don't support multiple processes :(
 			if (pshare) goto Polyfill;
 			sigset_t m = __sig_block ();
-			rc = nsync_futex_wait_win32_ (w, expect, pshare, clock, timeout, pt, m);
+			rc = cosmo_futex_wait_win32 (w, expect, pshare, clock, timeout, pt, m);
 			__sig_unblock (m);
 		} else if (IsXnu ()) {
 
@@ -293,7 +301,7 @@ int nsync_futex_wait_ (atomic_int *w, int expect, char pshare,
 				op = UL_COMPARE_AND_WAIT;
 			}
 			if (timeout) {
-				us = nsync_time_64to32u (timespec_tomicros (*timeout));
+				us = cosmo_time_64to32u (timespec_tomicros (*timeout));
 			} else {
 				us = -1u;
 			}
@@ -333,7 +341,7 @@ int nsync_futex_wait_ (atomic_int *w, int expect, char pshare,
 		}
 	} else {
 	Polyfill:
-		rc = nsync_futex_polyfill_ (w, expect, clock, timeout);
+		rc = cosmo_futex_polyfill (w, expect, clock, timeout);
 	}
 
 Finished:
@@ -346,18 +354,24 @@ Finished:
 	return rc;
 }
 
-int nsync_futex_wake_ (atomic_int *w, int count, char pshare) {
+/**
+ * Wakes futex.
+ *
+ * @param w is your futex
+ * @param count is number of threads to wake (usually 1 or `INT_MAX`)
+ * @param pshare is `PTHREAD_PROCESS_PRIVATE` / `PTHREAD_PROCESS_SHARED`
+ * @return number of threads woken on success, or -errno on error
+ */
+int cosmo_futex_wake (atomic_int *w, int count, char pshare) {
 	int rc, op, fop;
 
-	ASSERT (count == 1 || count == INT_MAX);
-
-	cosmo_once (&nsync_futex_.once, nsync_futex_init_);
+	cosmo_once (&g_cosmo_futex.once, cosmo_futex_init);
 
 	op = FUTEX_WAKE;
 	if (pshare == PTHREAD_PROCESS_PRIVATE)
-		op |= nsync_futex_.FUTEX_PRIVATE_FLAG_;
+		op |= g_cosmo_futex.FUTEX_PRIVATE_FLAG_;
 
-	if (nsync_futex_.is_supported) {
+	if (g_cosmo_futex.is_supported) {
 		if (IsWindows ()) {
 			if (pshare) {
 				goto Polyfill;
@@ -379,7 +393,7 @@ int nsync_futex_wake_ (atomic_int *w, int count, char pshare) {
 				op |= ULF_WAKE_ALL;
 			}
 			rc = ulock_wake (op, w, 0);
-			ASSERT (!rc || rc == -ENOENT);
+			unassert (!rc || rc == -ENOENT);
 			if (!rc) {
 				rc = 1;
 			} else if (rc == -ENOENT) {
diff --git a/libc/intrin/futex.S b/libc/intrin/cosmo_futex_thunk.S
similarity index 97%
rename from libc/intrin/futex.S
rename to libc/intrin/cosmo_futex_thunk.S
index 67c1d9822..1ce0d5917 100644
--- a/libc/intrin/futex.S
+++ b/libc/intrin/cosmo_futex_thunk.S
@@ -20,7 +20,7 @@
 #include "libc/macros.h"
 .privileged
 
-_futex:
+cosmo_futex_thunk:
 #ifdef __x86_64__
 	push	%rbp
 	mov	%rsp,%rbp
@@ -47,4 +47,4 @@ _futex:
 #error "unsupported architecture"
 #endif /* __x86_64__ */
 1:	ret
-	.endfn	_futex,globl,hidden
+	.endfn	cosmo_futex_thunk,globl,hidden
diff --git a/libc/calls/getcontext.S b/libc/intrin/getcontext.S
similarity index 98%
rename from libc/calls/getcontext.S
rename to libc/intrin/getcontext.S
index a05f5c83c..8be4f58eb 100644
--- a/libc/calls/getcontext.S
+++ b/libc/intrin/getcontext.S
@@ -27,6 +27,6 @@
 	.ftrace1
 getcontext:
 	.ftrace2
-#include "libc/calls/getcontext.inc"
+#include "libc/intrin/getcontext.inc"
 	jmp	__getcontextsig
 	.endfn	getcontext,globl
diff --git a/libc/calls/getcontext.inc b/libc/intrin/getcontext.inc
similarity index 100%
rename from libc/calls/getcontext.inc
rename to libc/intrin/getcontext.inc
diff --git a/libc/intrin/pthread_mutex_lock.c b/libc/intrin/pthread_mutex_lock.c
index 818fec3f2..ea2c7d09c 100644
--- a/libc/intrin/pthread_mutex_lock.c
+++ b/libc/intrin/pthread_mutex_lock.c
@@ -19,6 +19,7 @@
 #include "libc/calls/blockcancel.internal.h"
 #include "libc/calls/calls.h"
 #include "libc/calls/state.internal.h"
+#include "libc/cosmo.h"
 #include "libc/dce.h"
 #include "libc/errno.h"
 #include "libc/intrin/atomic.h"
@@ -28,25 +29,8 @@
 #include "libc/runtime/internal.h"
 #include "libc/thread/lock.h"
 #include "libc/thread/thread.h"
-#include "third_party/nsync/futex.internal.h"
 #include "third_party/nsync/mu.h"
 
-static void pthread_mutex_lock_spin(atomic_int *word) {
-  int backoff = 0;
-  if (atomic_exchange_explicit(word, 1, memory_order_acquire)) {
-    LOCKTRACE("acquiring pthread_mutex_lock_spin(%t)...", word);
-    for (;;) {
-      for (;;) {
-        if (!atomic_load_explicit(word, memory_order_relaxed))
-          break;
-        backoff = pthread_delay_np(word, backoff);
-      }
-      if (!atomic_exchange_explicit(word, 1, memory_order_acquire))
-        break;
-    }
-  }
-}
-
 // see "take 3" algorithm in "futexes are tricky" by ulrich drepper
 // slightly improved to attempt acquiring multiple times b4 syscall
 static void pthread_mutex_lock_drepper(atomic_int *futex, char pshare) {
@@ -59,7 +43,7 @@ static void pthread_mutex_lock_drepper(atomic_int *futex, char pshare) {
     word = atomic_exchange_explicit(futex, 2, memory_order_acquire);
   BLOCK_CANCELATION;
   while (word > 0) {
-    _weaken(nsync_futex_wait_)(futex, 2, pshare, 0, 0);
+    cosmo_futex_wait(futex, 2, pshare, 0, 0);
     word = atomic_exchange_explicit(futex, 2, memory_order_acquire);
   }
   ALLOW_CANCELATION;
@@ -164,11 +148,7 @@ static errno_t pthread_mutex_lock_impl(pthread_mutex_t *mutex) {
 
   // handle normal mutexes
   if (MUTEX_TYPE(word) == PTHREAD_MUTEX_NORMAL) {
-    if (_weaken(nsync_futex_wait_)) {
-      pthread_mutex_lock_drepper(&mutex->_futex, MUTEX_PSHARED(word));
-    } else {
-      pthread_mutex_lock_spin(&mutex->_futex);
-    }
+    pthread_mutex_lock_drepper(&mutex->_futex, MUTEX_PSHARED(word));
     return 0;
   }
 
diff --git a/libc/intrin/pthread_mutex_trylock.c b/libc/intrin/pthread_mutex_trylock.c
index 39607de5f..8391ebfe7 100644
--- a/libc/intrin/pthread_mutex_trylock.c
+++ b/libc/intrin/pthread_mutex_trylock.c
@@ -24,15 +24,8 @@
 #include "libc/runtime/internal.h"
 #include "libc/thread/lock.h"
 #include "libc/thread/thread.h"
-#include "third_party/nsync/futex.internal.h"
 #include "third_party/nsync/mu.h"
 
-static errno_t pthread_mutex_trylock_spin(atomic_int *word) {
-  if (!atomic_exchange_explicit(word, 1, memory_order_acquire))
-    return 0;
-  return EBUSY;
-}
-
 static errno_t pthread_mutex_trylock_drepper(atomic_int *futex) {
   int word = 0;
   if (atomic_compare_exchange_strong_explicit(
@@ -142,13 +135,8 @@ errno_t pthread_mutex_trylock(pthread_mutex_t *mutex) {
 #endif
 
   // handle normal mutexes
-  if (MUTEX_TYPE(word) == PTHREAD_MUTEX_NORMAL) {
-    if (_weaken(nsync_futex_wait_)) {
-      return pthread_mutex_trylock_drepper(&mutex->_futex);
-    } else {
-      return pthread_mutex_trylock_spin(&mutex->_futex);
-    }
-  }
+  if (MUTEX_TYPE(word) == PTHREAD_MUTEX_NORMAL)
+    return pthread_mutex_trylock_drepper(&mutex->_futex);
 
   // handle recursive and error checking mutexes
 #if PTHREAD_USE_NSYNC
diff --git a/libc/intrin/pthread_mutex_unlock.c b/libc/intrin/pthread_mutex_unlock.c
index ec9a90cae..a1a224a9c 100644
--- a/libc/intrin/pthread_mutex_unlock.c
+++ b/libc/intrin/pthread_mutex_unlock.c
@@ -18,6 +18,7 @@
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/calls/calls.h"
 #include "libc/calls/state.internal.h"
+#include "libc/cosmo.h"
 #include "libc/dce.h"
 #include "libc/errno.h"
 #include "libc/intrin/atomic.h"
@@ -26,19 +27,14 @@
 #include "libc/runtime/internal.h"
 #include "libc/thread/lock.h"
 #include "libc/thread/thread.h"
-#include "third_party/nsync/futex.internal.h"
 #include "third_party/nsync/mu.h"
 
-static void pthread_mutex_unlock_spin(atomic_int *word) {
-  atomic_store_explicit(word, 0, memory_order_release);
-}
-
 // see "take 3" algorithm in "futexes are tricky" by ulrich drepper
 static void pthread_mutex_unlock_drepper(atomic_int *futex, char pshare) {
   int word = atomic_fetch_sub_explicit(futex, 1, memory_order_release);
   if (word == 2) {
     atomic_store_explicit(futex, 0, memory_order_release);
-    _weaken(nsync_futex_wake_)(futex, 1, pshare);
+    cosmo_futex_wake(futex, 1, pshare);
   }
 }
 
@@ -137,11 +133,7 @@ errno_t pthread_mutex_unlock(pthread_mutex_t *mutex) {
 
   // implement barebones normal mutexes
   if (MUTEX_TYPE(word) == PTHREAD_MUTEX_NORMAL) {
-    if (_weaken(nsync_futex_wake_)) {
-      pthread_mutex_unlock_drepper(&mutex->_futex, MUTEX_PSHARED(word));
-    } else {
-      pthread_mutex_unlock_spin(&mutex->_futex);
-    }
+    pthread_mutex_unlock_drepper(&mutex->_futex, MUTEX_PSHARED(word));
     return 0;
   }
 
diff --git a/libc/calls/restore.S b/libc/intrin/restore.S
similarity index 100%
rename from libc/calls/restore.S
rename to libc/intrin/restore.S
diff --git a/libc/intrin/sig.c b/libc/intrin/sig.c
index 4fdd97914..7292b6701 100644
--- a/libc/intrin/sig.c
+++ b/libc/intrin/sig.c
@@ -1,7 +1,7 @@
 /*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
 │ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8                               :vi │
 ╞══════════════════════════════════════════════════════════════════════════════╡
-│ Copyright 2023 Justine Alexandra Roberts Tunney                              │
+│ Copyright 2022 Justine Alexandra Roberts Tunney                              │
 │                                                                              │
 │ Permission to use, copy, modify, and/or distribute this software for         │
 │ any purpose with or without fee is hereby granted, provided that the         │
@@ -17,37 +17,701 @@
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/sysv/consts/sig.h"
+#include "ape/sections.internal.h"
+#include "libc/calls/calls.h"
 #include "libc/calls/sig.internal.h"
+#include "libc/calls/state.internal.h"
+#include "libc/calls/struct/sigaction.h"
+#include "libc/calls/struct/siginfo.h"
 #include "libc/calls/struct/sigset.internal.h"
+#include "libc/calls/struct/ucontext.internal.h"
+#include "libc/calls/syscall_support-nt.internal.h"
+#include "libc/calls/ucontext.h"
 #include "libc/dce.h"
+#include "libc/errno.h"
 #include "libc/intrin/atomic.h"
+#include "libc/intrin/bsf.h"
+#include "libc/intrin/describebacktrace.h"
+#include "libc/intrin/dll.h"
+#include "libc/intrin/maps.h"
+#include "libc/intrin/strace.h"
 #include "libc/intrin/weaken.h"
-#include "libc/thread/tls.h"
+#include "libc/nt/console.h"
+#include "libc/nt/enum/context.h"
+#include "libc/nt/enum/exceptionhandleractions.h"
+#include "libc/nt/enum/processcreationflags.h"
+#include "libc/nt/enum/signal.h"
+#include "libc/nt/enum/status.h"
+#include "libc/nt/events.h"
+#include "libc/nt/runtime.h"
+#include "libc/nt/signals.h"
+#include "libc/nt/struct/ntexceptionpointers.h"
+#include "libc/nt/synchronization.h"
+#include "libc/nt/thread.h"
+#include "libc/runtime/internal.h"
+#include "libc/runtime/symbols.internal.h"
+#include "libc/str/str.h"
+#include "libc/sysv/consts/sa.h"
+#include "libc/sysv/consts/sicode.h"
+#include "libc/sysv/consts/ss.h"
+#include "libc/thread/posixthread.internal.h"
+#ifdef __x86_64__
 
-struct Signals __sig;
+/**
+ * @fileoverview Cosmopolitan Signals for Windows.
+ */
 
-sigset_t __sig_block(void) {
-  if (IsWindows() || IsMetal()) {
-    if (__tls_enabled)
-      return atomic_exchange_explicit(&__get_tls()->tib_sigmask, -1,
-                                      memory_order_acquire);
-    else
+#define STKSZ 65536
+
+struct SignalFrame {
+  unsigned rva;
+  unsigned flags;
+  siginfo_t si;
+  ucontext_t ctx;
+};
+
+static textwindows bool __sig_ignored_by_default(int sig) {
+  return sig == SIGURG ||   //
+         sig == SIGCONT ||  //
+         sig == SIGCHLD ||  //
+         sig == SIGWINCH;
+}
+
+textwindows bool __sig_ignored(int sig) {
+  return __sighandrvas[sig] == (intptr_t)SIG_IGN ||
+         (__sighandrvas[sig] == (intptr_t)SIG_DFL &&
+          __sig_ignored_by_default(sig));
+}
+
+textwindows void __sig_delete(int sig) {
+  struct Dll *e;
+  atomic_fetch_and_explicit(__sig.process, ~(1ull << (sig - 1)),
+                            memory_order_relaxed);
+  _pthread_lock();
+  for (e = dll_last(_pthread_list); e; e = dll_prev(_pthread_list, e))
+    atomic_fetch_and_explicit(&POSIXTHREAD_CONTAINER(e)->tib->tib_sigpending,
+                              ~(1ull << (sig - 1)), memory_order_relaxed);
+  _pthread_unlock();
+}
+
+static textwindows int __sig_getter(atomic_ulong *sigs, sigset_t masked) {
+  int sig;
+  sigset_t bit, pending, deliverable;
+  for (;;) {
+    pending = atomic_load_explicit(sigs, memory_order_acquire);
+    if ((deliverable = pending & ~masked)) {
+      sig = bsfl(deliverable) + 1;
+      bit = 1ull << (sig - 1);
+      if (atomic_fetch_and_explicit(sigs, ~bit, memory_order_acq_rel) & bit)
+        return sig;
+    } else {
       return 0;
-  } else {
-    sigset_t res, neu = -1;
-    sys_sigprocmask(SIG_SETMASK, &neu, &res);
-    return res;
+    }
   }
 }
 
-void __sig_unblock(sigset_t m) {
-  if (IsWindows() || IsMetal()) {
-    if (__tls_enabled) {
-      atomic_store_explicit(&__get_tls()->tib_sigmask, m, memory_order_release);
-      if (_weaken(__sig_check))
-        _weaken(__sig_check)();
+textwindows int __sig_get(sigset_t masked) {
+  int sig;
+  if (!(sig = __sig_getter(&__get_tls()->tib_sigpending, masked)))
+    sig = __sig_getter(__sig.process, masked);
+  return sig;
+}
+
+static textwindows bool __sig_should_use_altstack(unsigned flags,
+                                                  struct CosmoTib *tib) {
+  if (!(flags & SA_ONSTACK))
+    return false;  // signal handler didn't enable it
+  if (!tib->tib_sigstack_size)
+    return false;  // sigaltstack() wasn't installed on this thread
+  if (tib->tib_sigstack_flags & SS_DISABLE)
+    return false;  // sigaltstack() on this thread was disabled by user
+  char *bp = __builtin_frame_address(0);
+  if (tib->tib_sigstack_addr <= bp &&
+      bp <= tib->tib_sigstack_addr + tib->tib_sigstack_size)
+    return false;  // we're already on the alternate stack
+  return true;
+}
+
+static textwindows wontreturn void __sig_terminate(int sig) {
+  TerminateThisProcess(sig);
+}
+
+textwindows static bool __sig_wake(struct PosixThread *pt, int sig) {
+  atomic_int *blocker;
+  blocker = atomic_load_explicit(&pt->pt_blocker, memory_order_acquire);
+  if (!blocker)
+    return false;
+  // threads can create semaphores on an as-needed basis
+  if (blocker == PT_BLOCKER_EVENT) {
+    STRACE("%G set %d's event object", sig, _pthread_tid(pt));
+    SetEvent(pt->pt_event);
+    return !!atomic_load_explicit(&pt->pt_blocker, memory_order_acquire);
+  }
+  // all other blocking ops that aren't overlap should use futexes
+  // we force restartable futexes to churn by waking w/o releasing
+  STRACE("%G waking %d's futex", sig, _pthread_tid(pt));
+  WakeByAddressSingle(blocker);
+  return !!atomic_load_explicit(&pt->pt_blocker, memory_order_acquire);
+}
+
+textwindows static bool __sig_start(struct PosixThread *pt, int sig,
+                                    unsigned *rva, unsigned *flags) {
+  *rva = __sighandrvas[sig];
+  *flags = __sighandflags[sig];
+  if (*rva == (intptr_t)SIG_IGN ||
+      (*rva == (intptr_t)SIG_DFL && __sig_ignored_by_default(sig))) {
+    STRACE("ignoring %G", sig);
+    return false;
+  }
+  if (atomic_load_explicit(&pt->tib->tib_sigmask, memory_order_acquire) &
+      (1ull << (sig - 1))) {
+    STRACE("enqueing %G on %d", sig, _pthread_tid(pt));
+    atomic_fetch_or_explicit(&pt->tib->tib_sigpending, 1ull << (sig - 1),
+                             memory_order_relaxed);
+    __sig_wake(pt, sig);
+    return false;
+  }
+  if (*rva == (intptr_t)SIG_DFL) {
+    STRACE("terminating on %G due to no handler", sig);
+    __sig_terminate(sig);
+  }
+  return true;
+}
+
+textwindows static sigaction_f __sig_handler(unsigned rva) {
+  atomic_fetch_add_explicit(&__sig.count, 1, memory_order_relaxed);
+  return (sigaction_f)(__executable_start + rva);
+}
+
+textwindows int __sig_raise(volatile int sig, int sic) {
+
+  // bitset of kinds of handlers called
+  volatile int handler_was_called = 0;
+
+  // loop over pending signals
+  ucontext_t ctx;
+  getcontext(&ctx);
+  if (!sig) {
+    if ((sig = __sig_get(ctx.uc_sigmask))) {
+      sic = SI_KERNEL;
+    } else {
+      return handler_was_called;
+    }
+  }
+
+  // process signal(s)
+  unsigned rva, flags;
+  struct PosixThread *pt = _pthread_self();
+  if (__sig_start(pt, sig, &rva, &flags)) {
+
+    if (flags & SA_RESETHAND) {
+      STRACE("resetting %G handler", sig);
+      __sighandrvas[sig] = (int32_t)(intptr_t)SIG_DFL;
+    }
+
+    // update the signal mask in preparation for signal handller
+    sigset_t blocksigs = __sighandmask[sig];
+    if (!(flags & SA_NODEFER))
+      blocksigs |= 1ull << (sig - 1);
+    ctx.uc_sigmask = atomic_fetch_or_explicit(&pt->tib->tib_sigmask, blocksigs,
+                                              memory_order_acquire);
+
+    // call the user's signal handler
+    char ssbuf[128];
+    siginfo_t si = {.si_signo = sig, .si_code = sic};
+    STRACE("__sig_raise(%G, %t) mask %s", sig, __sig_handler(rva),
+           _DescribeSigset(ssbuf, 0, (sigset_t *)&pt->tib->tib_sigmask));
+    __sig_handler(rva)(sig, &si, &ctx);
+
+    // record this handler
+    if (flags & SA_RESTART) {
+      handler_was_called |= SIG_HANDLED_SA_RESTART;
+    } else {
+      handler_was_called |= SIG_HANDLED_NO_RESTART;
+    }
+  }
+
+  // restore sigmask
+  // loop back to top
+  // jump where handler says
+  sig = 0;
+  return setcontext(&ctx);
+}
+
+textwindows int __sig_relay(int sig, int sic, sigset_t waitmask) {
+  sigset_t m;
+  int handler_was_called;
+  m = atomic_exchange_explicit(&__get_tls()->tib_sigmask, waitmask,
+                               memory_order_acquire);
+  handler_was_called = __sig_raise(sig, SI_KERNEL);
+  atomic_store_explicit(&__get_tls()->tib_sigmask, m, memory_order_release);
+  return handler_was_called;
+}
+
+// the user's signal handler callback is wrapped with this trampoline
+static textwindows wontreturn void __sig_tramp(struct SignalFrame *sf) {
+  int sig = sf->si.si_signo;
+  struct CosmoTib *tib = __get_tls();
+  struct PosixThread *pt = (struct PosixThread *)tib->tib_pthread;
+  atomic_store_explicit(&pt->pt_intoff, 0, memory_order_release);
+  for (;;) {
+
+    // update the signal mask in preparation for signal handler
+    sigset_t blocksigs = __sighandmask[sig];
+    if (!(sf->flags & SA_NODEFER))
+      blocksigs |= 1ull << (sig - 1);
+    sf->ctx.uc_sigmask = atomic_fetch_or_explicit(&tib->tib_sigmask, blocksigs,
+                                                  memory_order_acquire);
+
+    // call the user's signal handler
+    char ssbuf[2][128];
+    STRACE("__sig_tramp(%G, %t) mask %s → %s", sig, __sig_handler(sf->rva),
+           _DescribeSigset(ssbuf[0], 0, &sf->ctx.uc_sigmask),
+           _DescribeSigset(ssbuf[1], 0, (sigset_t *)&tib->tib_sigmask));
+    __sig_handler(sf->rva)(sig, &sf->si, &sf->ctx);
+
+    // restore the signal mask that was used by the interrupted code
+    // this may have been modified by the signal handler in the callback
+    atomic_store_explicit(&tib->tib_sigmask, sf->ctx.uc_sigmask,
+                          memory_order_release);
+
+    // jump back into original code if there aren't any pending signals
+    do {
+      if (!(sig = __sig_get(sf->ctx.uc_sigmask)))
+        __sig_restore(&sf->ctx);
+    } while (!__sig_start(pt, sig, &sf->rva, &sf->flags));
+
+    // tail recurse into another signal handler
+    sf->si.si_signo = sig;
+    sf->si.si_code = SI_KERNEL;
+    if (sf->flags & SA_RESETHAND) {
+      STRACE("resetting %G handler", sig);
+      __sighandrvas[sig] = (int32_t)(intptr_t)SIG_DFL;
     }
-  } else {
-    sys_sigprocmask(SIG_SETMASK, &m, 0);
   }
 }
+
+// sends signal to another specific thread which is ref'd
+static textwindows int __sig_killer(struct PosixThread *pt, int sig, int sic) {
+  unsigned rva = __sighandrvas[sig];
+  unsigned flags = __sighandflags[sig];
+
+  // do nothing if signal is ignored
+  if (rva == (intptr_t)SIG_IGN ||
+      (rva == (intptr_t)SIG_DFL && __sig_ignored_by_default(sig))) {
+    STRACE("ignoring %G", sig);
+    return 0;
+  }
+
+  // we can't preempt threads that masked sigs or are blocked on i/o
+  while ((atomic_load_explicit(&pt->tib->tib_sigmask, memory_order_acquire) &
+          (1ull << (sig - 1)))) {
+    if (atomic_fetch_or_explicit(&pt->tib->tib_sigpending, 1ull << (sig - 1),
+                                 memory_order_acq_rel) &
+        (1ull << (sig - 1)))
+      // we believe signal was already enqueued
+      return 0;
+    if (__sig_wake(pt, sig))
+      // we believe i/o routine will handle signal
+      return 0;
+    if (atomic_load_explicit(&pt->tib->tib_sigmask, memory_order_acquire) &
+        (1ull << (sig - 1)))
+      // we believe ALLOW_SIGNALS will handle signal
+      return 0;
+    if (!(atomic_fetch_and_explicit(&pt->tib->tib_sigpending,
+                                    ~(1ull << (sig - 1)),
+                                    memory_order_acq_rel) &
+          (1ull << (sig - 1))))
+      // we believe another thread sniped our signal
+      return 0;
+    break;
+  }
+
+  // avoid race conditions and deadlocks with thread suspend process
+  if (atomic_exchange_explicit(&pt->pt_intoff, 1, memory_order_acquire)) {
+    // we believe another thread is asynchronously waking the mark
+    if (atomic_fetch_or_explicit(&pt->tib->tib_sigpending, 1ull << (sig - 1),
+                                 memory_order_acq_rel) &
+        (1ull << (sig - 1)))
+      // we believe our signal is already being delivered
+      return 0;
+    if (atomic_load_explicit(&pt->pt_intoff, memory_order_acquire) ||
+        atomic_exchange_explicit(&pt->pt_intoff, 1, memory_order_acquire))
+      // we believe __sig_tramp will deliver our signal
+      return 0;
+    if (!(atomic_fetch_and_explicit(&pt->tib->tib_sigpending,
+                                    ~(1ull << (sig - 1)),
+                                    memory_order_acq_rel) &
+          (1ull << (sig - 1))))
+      // we believe another thread sniped our signal
+      return 0;
+  }
+
+  // if there's no handler then killing a thread kills the process
+  if (rva == (intptr_t)SIG_DFL) {
+    STRACE("terminating on %G due to no handler", sig);
+    __sig_terminate(sig);
+  }
+
+  // take control of thread
+  // suspending the thread happens asynchronously
+  // however getting the context blocks until it's frozen
+  uintptr_t th = _pthread_syshand(pt);
+  if (SuspendThread(th) == -1u) {
+    STRACE("SuspendThread failed w/ %d", GetLastError());
+    atomic_store_explicit(&pt->pt_intoff, 0, memory_order_release);
+    return ESRCH;
+  }
+  struct NtContext nc;
+  nc.ContextFlags = kNtContextFull;
+  if (!GetThreadContext(th, &nc)) {
+    STRACE("GetThreadContext failed w/ %d", GetLastError());
+    ResumeThread(th);
+    atomic_store_explicit(&pt->pt_intoff, 0, memory_order_release);
+    return ESRCH;
+  }
+
+  // we can't preempt threads that masked sig or are blocked
+  // we can't preempt threads that are running in win32 code
+  // so we shall unblock the thread and let it signal itself
+  if (!((uintptr_t)__executable_start <= nc.Rip &&
+        nc.Rip < (uintptr_t)__privileged_start)) {
+    atomic_fetch_or_explicit(&pt->tib->tib_sigpending, 1ull << (sig - 1),
+                             memory_order_relaxed);
+    ResumeThread(th);
+    atomic_store_explicit(&pt->pt_intoff, 0, memory_order_release);
+    __sig_wake(pt, sig);
+    return 0;
+  }
+
+  // preferring to live dangerously
+  // the thread will be signaled asynchronously
+  if (flags & SA_RESETHAND) {
+    STRACE("resetting %G handler", sig);
+    __sighandrvas[sig] = (int32_t)(intptr_t)SIG_DFL;
+  }
+
+  // inject call to trampoline function into thread
+  uintptr_t sp;
+  if (__sig_should_use_altstack(flags, pt->tib)) {
+    sp = (uintptr_t)pt->tib->tib_sigstack_addr + pt->tib->tib_sigstack_size;
+  } else {
+    sp = nc.Rsp;
+  }
+  sp -= sizeof(struct SignalFrame);
+  sp &= -16;
+  struct SignalFrame *sf = (struct SignalFrame *)sp;
+  _ntcontext2linux(&sf->ctx, &nc);
+  bzero(&sf->si, sizeof(sf->si));
+  sf->rva = rva;
+  sf->flags = flags;
+  sf->si.si_code = sic;
+  sf->si.si_signo = sig;
+  *(uintptr_t *)(sp -= sizeof(uintptr_t)) = nc.Rip;
+  nc.Rip = (intptr_t)__sig_tramp;
+  nc.Rdi = (intptr_t)sf;
+  nc.Rsp = sp;
+  if (!SetThreadContext(th, &nc)) {
+    STRACE("SetThreadContext failed w/ %d", GetLastError());
+    atomic_store_explicit(&pt->pt_intoff, 0, memory_order_release);
+    return ESRCH;
+  }
+  ResumeThread(th);
+  __sig_wake(pt, sig);
+  return 0;
+}
+
+// sends signal to another specific thread
+textwindows int __sig_kill(struct PosixThread *pt, int sig, int sic) {
+  int rc;
+  BLOCK_SIGNALS;
+  rc = __sig_killer(pt, sig, sic);
+  ALLOW_SIGNALS;
+  return rc;
+}
+
+// sends signal to any other thread
+// this should only be called by non-posix threads
+textwindows void __sig_generate(int sig, int sic) {
+  struct Dll *e;
+  struct PosixThread *pt, *mark = 0;
+  if (__sig_ignored(sig)) {
+    STRACE("ignoring %G", sig);
+    return;
+  }
+  if (__sighandrvas[sig] == (intptr_t)SIG_DFL) {
+    STRACE("terminating on %G due to no handler", sig);
+    __sig_terminate(sig);
+  }
+  if (atomic_load_explicit(__sig.process, memory_order_acquire) &
+      (1ull << (sig - 1))) {
+    return;
+  }
+  _pthread_lock();
+  for (e = dll_first(_pthread_list); e; e = dll_next(_pthread_list, e)) {
+    pt = POSIXTHREAD_CONTAINER(e);
+    // we don't want to signal ourself
+    if (pt == _pthread_self())
+      continue;
+    // we don't want to signal a thread that isn't running
+    if (atomic_load_explicit(&pt->pt_status, memory_order_acquire) >=
+        kPosixThreadTerminated) {
+      continue;
+    }
+    // choose this thread if it isn't masking sig
+    if (!(atomic_load_explicit(&pt->tib->tib_sigmask, memory_order_acquire) &
+          (1ull << (sig - 1)))) {
+      _pthread_ref(pt);
+      mark = pt;
+      break;
+    }
+    // if a thread is blocking then we check to see if it's planning
+    // to unblock our sig once the wait operation is completed; when
+    // that's the case we can cancel the thread's i/o to deliver sig
+    if (atomic_load_explicit(&pt->pt_blocker, memory_order_acquire) &&
+        !(pt->pt_blkmask & (1ull << (sig - 1)))) {
+      _pthread_ref(pt);
+      mark = pt;
+      break;
+    }
+  }
+  _pthread_unlock();
+  if (mark) {
+    // no lock needed since current thread is nameless and formless
+    __sig_killer(mark, sig, sic);
+    _pthread_unref(mark);
+  } else {
+    atomic_fetch_or_explicit(__sig.process, 1ull << (sig - 1),
+                             memory_order_relaxed);
+  }
+}
+
+static textwindows char *__sig_stpcpy(char *d, const char *s) {
+  size_t i;
+  for (i = 0;; ++i)
+    if (!(d[i] = s[i]))
+      return d + i;
+}
+
+static textwindows wontreturn void __sig_death(int sig, const char *thing) {
+#ifndef TINY
+  intptr_t hStderr;
+  char sigbuf[21], s[128], *p;
+  hStderr = GetStdHandle(kNtStdErrorHandle);
+  p = __sig_stpcpy(s, "Terminating on ");
+  p = __sig_stpcpy(p, thing);
+  p = __sig_stpcpy(p, strsignal_r(sig, sigbuf));
+  p = __sig_stpcpy(p,
+                   ". Pass --strace and/or ShowCrashReports() for details.\n");
+  WriteFile(hStderr, s, p - s, 0, 0);
+#endif
+  __sig_terminate(sig);
+}
+
+static textwindows void __sig_unmaskable(struct NtExceptionPointers *ep,
+                                         int code, int sig,
+                                         struct CosmoTib *tib) {
+
+  // log vital crash information reliably for --strace before doing much
+  // we don't print this without the flag since raw numbers scare people
+  // this needs at least one page of stack memory in order to get logged
+  // otherwise it'll print a warning message about the lack of stack mem
+  STRACE("win32 vectored exception 0x%08Xu raising %G "
+         "cosmoaddr2line %s %lx %s",
+         ep->ExceptionRecord->ExceptionCode, sig,
+         _weaken(FindDebugBinary) ? _weaken(FindDebugBinary)()
+                                  : program_invocation_name,
+         ep->ContextRecord->Rip,
+         DescribeBacktrace((struct StackFrame *)ep->ContextRecord->Rbp));
+
+  // if the user didn't install a signal handler for this unmaskable
+  // exception, then print a friendly helpful hint message to stderr
+  unsigned rva = __sighandrvas[sig];
+  if (rva == (intptr_t)SIG_DFL || rva == (intptr_t)SIG_IGN)
+    __sig_death(sig, "uncaught ");
+
+  // if this signal handler is configured to auto-reset to the default
+  // then that reset needs to happen before the user handler is called
+  unsigned flags = __sighandflags[sig];
+  if (flags & SA_RESETHAND) {
+    STRACE("resetting %G handler", sig);
+    __sighandrvas[sig] = (int32_t)(intptr_t)SIG_DFL;
+  }
+
+  // determine the true memory address at which fault occurred
+  // if this is a stack overflow then reapply guard protection
+  void *si_addr;
+  if (ep->ExceptionRecord->ExceptionCode == kNtSignalGuardPage) {
+    si_addr = (void *)ep->ExceptionRecord->ExceptionInformation[1];
+  } else {
+    si_addr = ep->ExceptionRecord->ExceptionAddress;
+  }
+
+  // call the user signal handler
+  // and a modifiable view of the faulting code's cpu state
+  // temporarily replace signal mask while calling crash handler
+  // abort process if sig is already blocked to avoid crash loop
+  // note ucontext_t is a hefty data structures on top of NtContext
+  ucontext_t ctx = {0};
+  siginfo_t si = {.si_signo = sig, .si_code = code, .si_addr = si_addr};
+  _ntcontext2linux(&ctx, ep->ContextRecord);
+  sigset_t blocksigs = __sighandmask[sig];
+  if (!(flags & SA_NODEFER))
+    blocksigs |= 1ull << (sig - 1);
+  ctx.uc_sigmask = atomic_fetch_or_explicit(&tib->tib_sigmask, blocksigs,
+                                            memory_order_acquire);
+  if (ctx.uc_sigmask & (1ull << (sig - 1))) {
+    __sig_death(sig, "masked ");
+    __sig_terminate(sig);
+  }
+  __sig_handler(rva)(sig, &si, &ctx);
+  atomic_store_explicit(&tib->tib_sigmask, ctx.uc_sigmask,
+                        memory_order_release);
+  _ntlinux2context(ep->ContextRecord, &ctx);
+}
+
+void __stack_call(struct NtExceptionPointers *, int, int, struct CosmoTib *,
+                  void (*)(struct NtExceptionPointers *, int, int,
+                           struct CosmoTib *),
+                  void *);
+
+//                         abashed the devil stood
+//                      and felt how awful goodness is
+__msabi dontinstrument unsigned __sig_crash(struct NtExceptionPointers *ep) {
+
+  // translate win32 to unix si_signo and si_code
+  int code, sig = __sig_crash_sig(ep->ExceptionRecord->ExceptionCode, &code);
+
+  // advance the instruction pointer to skip over debugger breakpoints
+  // this behavior is consistent with how unix kernels are implemented
+  if (sig == SIGTRAP) {
+    ep->ContextRecord->Rip++;
+    if (__sig_ignored(sig))
+      return kNtExceptionContinueExecution;
+  }
+
+  // win32 stack overflow detection executes INSIDE the guard page
+  // thus switch to the alternate signal stack as soon as possible
+  struct CosmoTib *tib = __get_tls();
+  unsigned flags = __sighandflags[sig];
+  if (__sig_should_use_altstack(flags, tib)) {
+    __stack_call(ep, code, sig, tib, __sig_unmaskable,
+                 tib->tib_sigstack_addr + tib->tib_sigstack_size);
+  } else {
+    __sig_unmaskable(ep, code, sig, tib);
+  }
+
+  // resume running user program
+  // hopefully the user fixed the cpu state
+  // otherwise the crash will keep happening
+  return kNtExceptionContinueExecution;
+}
+
+static textwindows int __sig_console_sig(uint32_t dwCtrlType) {
+  switch (dwCtrlType) {
+    case kNtCtrlCEvent:
+      return SIGINT;
+    case kNtCtrlBreakEvent:
+      return SIGQUIT;
+    case kNtCtrlCloseEvent:
+    case kNtCtrlLogoffEvent:    // only received by services
+    case kNtCtrlShutdownEvent:  // only received by services
+      return SIGHUP;
+    default:
+      return SIGSTKFLT;
+  }
+}
+
+__msabi textwindows dontinstrument bool32 __sig_console(uint32_t dwCtrlType) {
+  // win32 launches a thread to deliver ctrl-c and ctrl-break when typed
+  // it only happens when kNtEnableProcessedInput is in play on console.
+  // otherwise we need to wait until read-nt.c discovers that keystroke.
+  struct CosmoTib tls;
+  __bootstrap_tls(&tls, __builtin_frame_address(0));
+  __sig_generate(__sig_console_sig(dwCtrlType), SI_KERNEL);
+  return true;
+}
+
+// returns 0 if no signal handlers were called, otherwise a bitmask
+// consisting of `1` which means a signal handler was invoked which
+// didn't have the SA_RESTART flag, and `2`, which means SA_RESTART
+// handlers were called (or `3` if both were the case).
+textwindows int __sig_check(void) {
+  int sig, res = 0;
+  while ((sig = __sig_get(atomic_load_explicit(&__get_tls()->tib_sigmask,
+                                               memory_order_acquire))))
+    res |= __sig_raise(sig, SI_KERNEL);
+  return res;
+}
+
+// background thread for delivering inter-process signals asynchronously
+// this checks for undelivered process-wide signals, once per scheduling
+// quantum, which on windows should be every ~15ms or so, unless somehow
+// the process was tuned to have more fine-grained event timing. we want
+// signals to happen faster when possible; that happens when cancelation
+// points, e.g. read need to wait on i/o; they too check for new signals
+textwindows dontinstrument static uint32_t __sig_worker(void *arg) {
+  struct CosmoTib tls;
+  __bootstrap_tls(&tls, __builtin_frame_address(0));
+  char *sp = __builtin_frame_address(0);
+  __maps_track((char *)(((uintptr_t)sp + __pagesize - 1) & -__pagesize) - STKSZ,
+               STKSZ);
+  for (;;) {
+
+    // dequeue all pending signals and fire them off. if there's no
+    // thread that can handle them then __sig_generate will requeue
+    // those signals back to __sig.process; hence the need for xchg
+    unsigned long sigs =
+        atomic_exchange_explicit(__sig.process, 0, memory_order_acq_rel);
+    while (sigs) {
+      int sig = bsfl(sigs) + 1;
+      sigs &= ~(1ull << (sig - 1));
+      __sig_generate(sig, SI_KERNEL);
+    }
+
+    // unblock stalled asynchronous signals in threads
+    _pthread_lock();
+    for (struct Dll *e = dll_first(_pthread_list); e;
+         e = dll_next(_pthread_list, e)) {
+      struct PosixThread *pt = POSIXTHREAD_CONTAINER(e);
+      if (atomic_load_explicit(&pt->pt_status, memory_order_acquire) >=
+          kPosixThreadTerminated) {
+        break;
+      }
+      sigset_t pending =
+          atomic_load_explicit(&pt->tib->tib_sigpending, memory_order_acquire);
+      sigset_t mask =
+          atomic_load_explicit(&pt->tib->tib_sigmask, memory_order_acquire);
+      if (pending & ~mask) {
+        _pthread_ref(pt);
+        _pthread_unlock();
+        while (!atomic_compare_exchange_weak_explicit(
+            &pt->tib->tib_sigpending, &pending, pending & ~mask,
+            memory_order_acq_rel, memory_order_relaxed)) {
+        }
+        while ((pending = pending & ~mask)) {
+          int sig = bsfl(pending) + 1;
+          pending &= ~(1ull << (sig - 1));
+          __sig_killer(pt, sig, SI_KERNEL);
+        }
+        _pthread_lock();
+        _pthread_unref(pt);
+      }
+    }
+    _pthread_unlock();
+
+    // wait until next scheduler quantum
+    Sleep(POLL_INTERVAL_MS);
+  }
+  return 0;
+}
+
+__attribute__((__constructor__(10))) textstartup void __sig_init(void) {
+  if (!IsWindows())
+    return;
+  AddVectoredExceptionHandler(true, (void *)__sig_crash);
+  SetConsoleCtrlHandler((void *)__sig_console, true);
+  CreateThread(0, STKSZ, __sig_worker, 0, kNtStackSizeParamIsAReservation, 0);
+}
+
+#endif /* __x86_64__ */
diff --git a/libc/intrin/sigblock.c b/libc/intrin/sigblock.c
new file mode 100644
index 000000000..4fdd97914
--- /dev/null
+++ b/libc/intrin/sigblock.c
@@ -0,0 +1,53 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8                               :vi │
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2023 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ Permission to use, copy, modify, and/or distribute this software for         │
+│ any purpose with or without fee is hereby granted, provided that the         │
+│ above copyright notice and this permission notice appear in all copies.      │
+│                                                                              │
+│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
+│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
+│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
+│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
+│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
+│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
+│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
+│ PERFORMANCE OF THIS SOFTWARE.                                                │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/sysv/consts/sig.h"
+#include "libc/calls/sig.internal.h"
+#include "libc/calls/struct/sigset.internal.h"
+#include "libc/dce.h"
+#include "libc/intrin/atomic.h"
+#include "libc/intrin/weaken.h"
+#include "libc/thread/tls.h"
+
+struct Signals __sig;
+
+sigset_t __sig_block(void) {
+  if (IsWindows() || IsMetal()) {
+    if (__tls_enabled)
+      return atomic_exchange_explicit(&__get_tls()->tib_sigmask, -1,
+                                      memory_order_acquire);
+    else
+      return 0;
+  } else {
+    sigset_t res, neu = -1;
+    sys_sigprocmask(SIG_SETMASK, &neu, &res);
+    return res;
+  }
+}
+
+void __sig_unblock(sigset_t m) {
+  if (IsWindows() || IsMetal()) {
+    if (__tls_enabled) {
+      atomic_store_explicit(&__get_tls()->tib_sigmask, m, memory_order_release);
+      if (_weaken(__sig_check))
+        _weaken(__sig_check)();
+    }
+  } else {
+    sys_sigprocmask(SIG_SETMASK, &m, 0);
+  }
+}
diff --git a/libc/calls/sigcrashsig.c b/libc/intrin/sigcrashsig.c
similarity index 100%
rename from libc/calls/sigcrashsig.c
rename to libc/intrin/sigcrashsig.c
diff --git a/libc/calls/swapcontext.S b/libc/intrin/swapcontext.S
similarity index 98%
rename from libc/calls/swapcontext.S
rename to libc/intrin/swapcontext.S
index d7b96556f..6d2e517e6 100644
--- a/libc/calls/swapcontext.S
+++ b/libc/intrin/swapcontext.S
@@ -32,7 +32,7 @@
 	.ftrace1
 swapcontext:
 	.ftrace2
-#include "libc/calls/getcontext.inc"
+#include "libc/intrin/getcontext.inc"
 #ifdef __x86_64__
 	push	%rbp
 	mov	%rsp,%rbp
diff --git a/libc/calls/tailcontext.S b/libc/intrin/tailcontext.S
similarity index 100%
rename from libc/calls/tailcontext.S
rename to libc/intrin/tailcontext.S
diff --git a/libc/calls/timespec_add.c b/libc/intrin/timespec_add.c
similarity index 100%
rename from libc/calls/timespec_add.c
rename to libc/intrin/timespec_add.c
diff --git a/libc/calls/timespec_cmp.c b/libc/intrin/timespec_cmp.c
similarity index 100%
rename from libc/calls/timespec_cmp.c
rename to libc/intrin/timespec_cmp.c
diff --git a/libc/calls/timespec_frommicros.c b/libc/intrin/timespec_frommicros.c
similarity index 100%
rename from libc/calls/timespec_frommicros.c
rename to libc/intrin/timespec_frommicros.c
diff --git a/libc/calls/timespec_frommillis.c b/libc/intrin/timespec_frommillis.c
similarity index 100%
rename from libc/calls/timespec_frommillis.c
rename to libc/intrin/timespec_frommillis.c
diff --git a/libc/calls/timespec_fromnanos.c b/libc/intrin/timespec_fromnanos.c
similarity index 100%
rename from libc/calls/timespec_fromnanos.c
rename to libc/intrin/timespec_fromnanos.c
diff --git a/libc/calls/timespec_sub.c b/libc/intrin/timespec_sub.c
similarity index 100%
rename from libc/calls/timespec_sub.c
rename to libc/intrin/timespec_sub.c
diff --git a/libc/calls/timespec_subz.c b/libc/intrin/timespec_subz.c
similarity index 100%
rename from libc/calls/timespec_subz.c
rename to libc/intrin/timespec_subz.c
diff --git a/libc/calls/timespec_tomicros.c b/libc/intrin/timespec_tomicros.c
similarity index 100%
rename from libc/calls/timespec_tomicros.c
rename to libc/intrin/timespec_tomicros.c
diff --git a/libc/calls/timespec_tomillis.c b/libc/intrin/timespec_tomillis.c
similarity index 100%
rename from libc/calls/timespec_tomillis.c
rename to libc/intrin/timespec_tomillis.c
diff --git a/libc/calls/timespec_tonanos.c b/libc/intrin/timespec_tonanos.c
similarity index 100%
rename from libc/calls/timespec_tonanos.c
rename to libc/intrin/timespec_tonanos.c
diff --git a/libc/calls/timespec_totimeval.c b/libc/intrin/timespec_totimeval.c
similarity index 100%
rename from libc/calls/timespec_totimeval.c
rename to libc/intrin/timespec_totimeval.c
diff --git a/libc/str/timespectowindowstime.c b/libc/intrin/timespectowindowstime.c
similarity index 100%
rename from libc/str/timespectowindowstime.c
rename to libc/intrin/timespectowindowstime.c
diff --git a/libc/calls/timeval_add.c b/libc/intrin/timeval_add.c
similarity index 100%
rename from libc/calls/timeval_add.c
rename to libc/intrin/timeval_add.c
diff --git a/libc/calls/timeval_cmp.c b/libc/intrin/timeval_cmp.c
similarity index 100%
rename from libc/calls/timeval_cmp.c
rename to libc/intrin/timeval_cmp.c
diff --git a/libc/calls/timeval_frommicros.c b/libc/intrin/timeval_frommicros.c
similarity index 100%
rename from libc/calls/timeval_frommicros.c
rename to libc/intrin/timeval_frommicros.c
diff --git a/libc/calls/timeval_frommillis.c b/libc/intrin/timeval_frommillis.c
similarity index 100%
rename from libc/calls/timeval_frommillis.c
rename to libc/intrin/timeval_frommillis.c
diff --git a/libc/calls/timeval_sub.c b/libc/intrin/timeval_sub.c
similarity index 100%
rename from libc/calls/timeval_sub.c
rename to libc/intrin/timeval_sub.c
diff --git a/libc/calls/timeval_subz.c b/libc/intrin/timeval_subz.c
similarity index 100%
rename from libc/calls/timeval_subz.c
rename to libc/intrin/timeval_subz.c
diff --git a/libc/calls/timeval_tomicros.c b/libc/intrin/timeval_tomicros.c
similarity index 100%
rename from libc/calls/timeval_tomicros.c
rename to libc/intrin/timeval_tomicros.c
diff --git a/libc/calls/timeval_tomillis.c b/libc/intrin/timeval_tomillis.c
similarity index 100%
rename from libc/calls/timeval_tomillis.c
rename to libc/intrin/timeval_tomillis.c
diff --git a/libc/calls/timeval_toseconds.c b/libc/intrin/timeval_toseconds.c
similarity index 100%
rename from libc/calls/timeval_toseconds.c
rename to libc/intrin/timeval_toseconds.c
diff --git a/libc/str/timevaltowindowstime.c b/libc/intrin/timevaltowindowstime.c
similarity index 100%
rename from libc/str/timevaltowindowstime.c
rename to libc/intrin/timevaltowindowstime.c
diff --git a/libc/calls/ucontext.c b/libc/intrin/ucontext.c
similarity index 100%
rename from libc/calls/ucontext.c
rename to libc/intrin/ucontext.c
diff --git a/libc/calls/vdsofunc.greg.c b/libc/intrin/vdsofunc.c
similarity index 100%
rename from libc/calls/vdsofunc.greg.c
rename to libc/intrin/vdsofunc.c
diff --git a/libc/str/windowsdurationtotimespec.c b/libc/intrin/windowsdurationtotimespec.c
similarity index 100%
rename from libc/str/windowsdurationtotimespec.c
rename to libc/intrin/windowsdurationtotimespec.c
diff --git a/libc/str/windowsdurationtotimeval.c b/libc/intrin/windowsdurationtotimeval.c
similarity index 100%
rename from libc/str/windowsdurationtotimeval.c
rename to libc/intrin/windowsdurationtotimeval.c
diff --git a/libc/str/windowstimetotimespec.c b/libc/intrin/windowstimetotimespec.c
similarity index 100%
rename from libc/str/windowstimetotimespec.c
rename to libc/intrin/windowstimetotimespec.c
diff --git a/libc/str/windowstimetotimeval.c b/libc/intrin/windowstimetotimeval.c
similarity index 100%
rename from libc/str/windowstimetotimeval.c
rename to libc/intrin/windowstimetotimeval.c
diff --git a/libc/str/BUILD.mk b/libc/str/BUILD.mk
index 5e10f4ace..b0b2a163a 100644
--- a/libc/str/BUILD.mk
+++ b/libc/str/BUILD.mk
@@ -77,13 +77,7 @@ o/$(MODE)/libc/str/iswseparator.o: private			\
 
 # ensure that division is optimized
 o/$(MODE)/libc/str/bcmp.o					\
-o/$(MODE)/libc/str/strcmp.o					\
-o/$(MODE)/libc/str/windowsdurationtotimeval.o			\
-o/$(MODE)/libc/str/windowsdurationtotimespec.o			\
-o/$(MODE)/libc/str/timevaltowindowstime.o			\
-o/$(MODE)/libc/str/timespectowindowstime.o			\
-o/$(MODE)/libc/str/windowstimetotimeval.o			\
-o/$(MODE)/libc/str/windowstimetotimespec.o: private		\
+o/$(MODE)/libc/str/strcmp.o: private				\
 		CFLAGS +=					\
 			-O2
 
diff --git a/libc/thread/pthread_barrier_wait.c b/libc/thread/pthread_barrier_wait.c
index a4d44bf5e..5a318feed 100644
--- a/libc/thread/pthread_barrier_wait.c
+++ b/libc/thread/pthread_barrier_wait.c
@@ -17,11 +17,11 @@
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/calls/blockcancel.internal.h"
+#include "libc/cosmo.h"
 #include "libc/errno.h"
 #include "libc/intrin/atomic.h"
 #include "libc/limits.h"
 #include "libc/thread/thread.h"
-#include "third_party/nsync/futex.internal.h"
 
 /**
  * Waits for all threads to arrive at barrier.
@@ -54,14 +54,14 @@ errno_t pthread_barrier_wait(pthread_barrier_t *barrier) {
     atomic_store_explicit(&barrier->_counter, barrier->_count,
                           memory_order_release);
     atomic_store_explicit(&barrier->_waiters, 0, memory_order_release);
-    nsync_futex_wake_(&barrier->_waiters, INT_MAX, barrier->_pshared);
+    cosmo_futex_wake(&barrier->_waiters, INT_MAX, barrier->_pshared);
     return PTHREAD_BARRIER_SERIAL_THREAD;
   }
 
   // wait for everyone else to arrive at barrier
   BLOCK_CANCELATION;
   while ((n = atomic_load_explicit(&barrier->_waiters, memory_order_acquire)))
-    nsync_futex_wait_(&barrier->_waiters, n, barrier->_pshared, 0, 0);
+    cosmo_futex_wait(&barrier->_waiters, n, barrier->_pshared, 0, 0);
   ALLOW_CANCELATION;
 
   return 0;
diff --git a/libc/thread/pthread_cond_broadcast.c b/libc/thread/pthread_cond_broadcast.c
index 236d476c8..f50d5b3ea 100644
--- a/libc/thread/pthread_cond_broadcast.c
+++ b/libc/thread/pthread_cond_broadcast.c
@@ -16,12 +16,12 @@
 │ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/cosmo.h"
 #include "libc/dce.h"
 #include "libc/intrin/atomic.h"
 #include "libc/limits.h"
 #include "libc/thread/thread.h"
 #include "third_party/nsync/cv.h"
-#include "third_party/nsync/futex.internal.h"
 
 __static_yoink("nsync_mu_lock");
 __static_yoink("nsync_mu_unlock");
@@ -63,6 +63,6 @@ errno_t pthread_cond_broadcast(pthread_cond_t *cond) {
   // roll forward the monotonic sequence
   atomic_fetch_add_explicit(&cond->_sequence, 1, memory_order_acq_rel);
   if (atomic_load_explicit(&cond->_waiters, memory_order_acquire))
-    nsync_futex_wake_((atomic_int *)&cond->_sequence, INT_MAX, cond->_pshared);
+    cosmo_futex_wake((atomic_int *)&cond->_sequence, INT_MAX, cond->_pshared);
   return 0;
 }
diff --git a/libc/thread/pthread_cond_signal.c b/libc/thread/pthread_cond_signal.c
index d3ac46844..b85522ad4 100644
--- a/libc/thread/pthread_cond_signal.c
+++ b/libc/thread/pthread_cond_signal.c
@@ -16,11 +16,11 @@
 │ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/cosmo.h"
 #include "libc/dce.h"
 #include "libc/intrin/atomic.h"
 #include "libc/thread/thread.h"
 #include "third_party/nsync/cv.h"
-#include "third_party/nsync/futex.internal.h"
 
 __static_yoink("nsync_mu_lock");
 __static_yoink("nsync_mu_unlock");
@@ -62,6 +62,6 @@ errno_t pthread_cond_signal(pthread_cond_t *cond) {
   // roll forward the monotonic sequence
   atomic_fetch_add_explicit(&cond->_sequence, 1, memory_order_acq_rel);
   if (atomic_load_explicit(&cond->_waiters, memory_order_acquire))
-    nsync_futex_wake_((atomic_int *)&cond->_sequence, 1, cond->_pshared);
+    cosmo_futex_wake((atomic_int *)&cond->_sequence, 1, cond->_pshared);
   return 0;
 }
diff --git a/libc/thread/pthread_cond_timedwait.c b/libc/thread/pthread_cond_timedwait.c
index 8e2225cfc..55ab6038c 100644
--- a/libc/thread/pthread_cond_timedwait.c
+++ b/libc/thread/pthread_cond_timedwait.c
@@ -18,6 +18,8 @@
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/calls/calls.h"
 #include "libc/calls/cp.internal.h"
+#include "libc/calls/struct/timespec.h"
+#include "libc/cosmo.h"
 #include "libc/dce.h"
 #include "libc/errno.h"
 #include "libc/intrin/atomic.h"
@@ -28,7 +30,6 @@
 #include "libc/thread/thread2.h"
 #include "third_party/nsync/common.internal.h"
 #include "third_party/nsync/cv.h"
-#include "third_party/nsync/futex.internal.h"
 #include "third_party/nsync/time.h"
 
 __static_yoink("nsync_mu_lock");
@@ -74,8 +75,8 @@ static errno_t pthread_cond_timedwait_impl(pthread_cond_t *cond,
   int rc;
   struct PthreadWait waiter = {cond, mutex};
   pthread_cleanup_push(pthread_cond_leave, &waiter);
-  rc = nsync_futex_wait_((atomic_int *)&cond->_sequence, seq1, cond->_pshared,
-                         cond->_clock, abstime);
+  rc = cosmo_futex_wait((atomic_int *)&cond->_sequence, seq1, cond->_pshared,
+                        cond->_clock, abstime);
   pthread_cleanup_pop(true);
   if (rc == -EAGAIN)
     rc = 0;
diff --git a/libc/thread/pthread_exit.c b/libc/thread/pthread_exit.c
index 0d625d4d7..78de70624 100644
--- a/libc/thread/pthread_exit.c
+++ b/libc/thread/pthread_exit.c
@@ -18,6 +18,7 @@
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/assert.h"
 #include "libc/atomic.h"
+#include "libc/cosmo.h"
 #include "libc/cxxabi.h"
 #include "libc/dce.h"
 #include "libc/intrin/atomic.h"
@@ -33,7 +34,6 @@
 #include "libc/thread/posixthread.internal.h"
 #include "libc/thread/thread.h"
 #include "libc/thread/tls.h"
-#include "third_party/nsync/futex.internal.h"
 #include "third_party/nsync/wait_s.internal.h"
 
 /**
@@ -137,8 +137,8 @@ wontreturn void pthread_exit(void *rc) {
   // note that the main thread is joinable by child threads
   if (pt->pt_flags & PT_STATIC) {
     atomic_store_explicit(&tib->tib_tid, 0, memory_order_release);
-    nsync_futex_wake_((atomic_int *)&tib->tib_tid, INT_MAX,
-                      !IsWindows() && !IsXnu());
+    cosmo_futex_wake((atomic_int *)&tib->tib_tid, INT_MAX,
+                     !IsWindows() && !IsXnu());
     _Exit1(0);
   }
 
diff --git a/libc/thread/pthread_timedjoin_np.c b/libc/thread/pthread_timedjoin_np.c
index 9199f2e53..9022a9196 100644
--- a/libc/thread/pthread_timedjoin_np.c
+++ b/libc/thread/pthread_timedjoin_np.c
@@ -20,6 +20,8 @@
 #include "libc/calls/cp.internal.h"
 #include "libc/calls/struct/timespec.h"
 #include "libc/calls/struct/timespec.internal.h"
+#include "libc/cosmo.h"
+#include "libc/dce.h"
 #include "libc/errno.h"
 #include "libc/fmt/itoa.h"
 #include "libc/intrin/atomic.h"
@@ -30,7 +32,6 @@
 #include "libc/thread/posixthread.internal.h"
 #include "libc/thread/thread2.h"
 #include "libc/thread/tls.h"
-#include "third_party/nsync/futex.internal.h"
 
 static const char *DescribeReturnValue(char buf[30], int err, void **value) {
   char *p = buf;
@@ -75,8 +76,8 @@ static errno_t _pthread_wait(atomic_int *ctid, struct timespec *abstime) {
     if (!(err = pthread_testcancel_np())) {
       BEGIN_CANCELATION_POINT;
       while ((x = atomic_load_explicit(ctid, memory_order_acquire))) {
-        e = nsync_futex_wait_(ctid, x, !IsWindows() && !IsXnu(), CLOCK_REALTIME,
-                              abstime);
+        e = cosmo_futex_wait(ctid, x, !IsWindows() && !IsXnu(), CLOCK_REALTIME,
+                             abstime);
         if (e == -ECANCELED) {
           err = ECANCELED;
           break;
diff --git a/libc/thread/sem_post.c b/libc/thread/sem_post.c
index 80c164c9e..8da481cc0 100644
--- a/libc/thread/sem_post.c
+++ b/libc/thread/sem_post.c
@@ -19,6 +19,7 @@
 #include "libc/assert.h"
 #include "libc/calls/calls.h"
 #include "libc/calls/syscall-sysv.internal.h"
+#include "libc/cosmo.h"
 #include "libc/dce.h"
 #include "libc/errno.h"
 #include "libc/intrin/atomic.h"
@@ -26,7 +27,6 @@
 #include "libc/runtime/syslib.internal.h"
 #include "libc/sysv/errfuns.h"
 #include "libc/thread/semaphore.h"
-#include "third_party/nsync/futex.internal.h"
 
 /**
  * Unlocks semaphore.
@@ -46,7 +46,7 @@ int sem_post(sem_t *sem) {
   old = atomic_fetch_add_explicit(&sem->sem_value, 1, memory_order_acq_rel);
   unassert(old > INT_MIN);
   if (old >= 0) {
-    wakeups = nsync_futex_wake_(&sem->sem_value, 1, sem->sem_pshared);
+    wakeups = cosmo_futex_wake(&sem->sem_value, 1, sem->sem_pshared);
     npassert(wakeups >= 0);
     rc = 0;
   } else {
diff --git a/libc/thread/sem_timedwait.c b/libc/thread/sem_timedwait.c
index be046ce6e..b68193fe6 100644
--- a/libc/thread/sem_timedwait.c
+++ b/libc/thread/sem_timedwait.c
@@ -22,6 +22,7 @@
 #include "libc/calls/struct/timespec.h"
 #include "libc/calls/struct/timespec.internal.h"
 #include "libc/calls/syscall-sysv.internal.h"
+#include "libc/cosmo.h"
 #include "libc/dce.h"
 #include "libc/errno.h"
 #include "libc/intrin/atomic.h"
@@ -32,7 +33,6 @@
 #include "libc/sysv/errfuns.h"
 #include "libc/thread/semaphore.h"
 #include "libc/thread/thread.h"
-#include "third_party/nsync/futex.internal.h"
 
 static void sem_delay(int n) {
   volatile int i;
@@ -119,8 +119,8 @@ int sem_timedwait(sem_t *sem, const struct timespec *abstime) {
 
   do {
     if (!(v = atomic_load_explicit(&sem->sem_value, memory_order_relaxed))) {
-      rc = nsync_futex_wait_(&sem->sem_value, v, sem->sem_pshared,
-                             CLOCK_REALTIME, abstime);
+      rc = cosmo_futex_wait(&sem->sem_value, v, sem->sem_pshared,
+                            CLOCK_REALTIME, abstime);
       if (rc == -EINTR || rc == -ECANCELED) {
         errno = -rc;
         rc = -1;
diff --git a/test/libc/thread/footek_test.c b/test/libc/thread/footek_test.c
index 51d3bd1c9..c089c1085 100644
--- a/test/libc/thread/footek_test.c
+++ b/test/libc/thread/footek_test.c
@@ -9,8 +9,6 @@
 
 #ifdef __COSMOPOLITAN__
 #include <cosmo.h>
-#include "libc/thread/thread.h"
-#include "third_party/nsync/futex.internal.h"
 #endif
 
 #include <assert.h>
diff --git a/third_party/lua/lunix.c b/third_party/lua/lunix.c
index 9a8b44877..b8e4219c7 100644
--- a/third_party/lua/lunix.c
+++ b/third_party/lua/lunix.c
@@ -109,8 +109,9 @@
 #include "third_party/lua/lgc.h"
 #include "third_party/lua/lua.h"
 #include "third_party/lua/luaconf.h"
-#include "third_party/nsync/futex.internal.h"
 #include "libc/sysv/consts/clock.h"
+#include "libc/cosmo.h"
+#include "libc/cosmo.h"
 #include "tool/net/luacheck.h"
 
 #define DNS_NAME_MAX  253
@@ -2855,7 +2856,7 @@ static int LuaUnixMemoryWait(lua_State *L) {
     deadline = &ts;
   }
   BEGIN_CANCELATION_POINT;
-  rc = nsync_futex_wait_((atomic_int *)GetWord(L), expect,
+  rc = cosmo_futex_wait((atomic_int *)GetWord(L), expect,
                          PTHREAD_PROCESS_SHARED, CLOCK_REALTIME, deadline);
   END_CANCELATION_POINT;
   if (rc < 0) errno = -rc, rc = -1;
@@ -2867,7 +2868,7 @@ static int LuaUnixMemoryWait(lua_State *L) {
 static int LuaUnixMemoryWake(lua_State *L) {
   int count, woken;
   count = luaL_optinteger(L, 3, INT_MAX);
-  woken = nsync_futex_wake_((atomic_int *)GetWord(L), count,
+  woken = cosmo_futex_wake((atomic_int *)GetWord(L), count,
                             PTHREAD_PROCESS_SHARED);
   npassert(woken >= 0);
   return ReturnInteger(L, woken);
diff --git a/third_party/nsync/BUILD.mk b/third_party/nsync/BUILD.mk
index b2e545c38..0b8ed2923 100644
--- a/third_party/nsync/BUILD.mk
+++ b/third_party/nsync/BUILD.mk
@@ -27,7 +27,6 @@ THIRD_PARTY_NSYNC_A_DIRECTDEPS =			\
 	LIBC_INTRIN					\
 	LIBC_NEXGEN32E					\
 	LIBC_NT_KERNEL32				\
-	LIBC_NT_SYNCHRONIZATION				\
 	LIBC_STR					\
 	LIBC_SYSV					\
 	LIBC_SYSV_CALLS
diff --git a/third_party/nsync/futex.internal.h b/third_party/nsync/futex.internal.h
deleted file mode 100644
index f555224ff..000000000
--- a/third_party/nsync/futex.internal.h
+++ /dev/null
@@ -1,17 +0,0 @@
-#ifndef NSYNC_FUTEX_INTERNAL_H_
-#define NSYNC_FUTEX_INTERNAL_H_
-#include "libc/calls/struct/timespec.h"
-#include "libc/dce.h"
-COSMOPOLITAN_C_START_
-
-#ifndef __cplusplus
-#define _FUTEX_ATOMIC(x) _Atomic(x)
-#else
-#define _FUTEX_ATOMIC(x) x
-#endif
-
-int nsync_futex_wake_(_FUTEX_ATOMIC(int) *, int, char);
-int nsync_futex_wait_(_FUTEX_ATOMIC(int) *, int, char, int, const struct timespec *);
-
-COSMOPOLITAN_C_END_
-#endif /* NSYNC_FUTEX_INTERNAL_H_ */
diff --git a/third_party/nsync/mu_semaphore_futex.c b/third_party/nsync/mu_semaphore_futex.c
index 051f5e907..7c06ccee7 100644
--- a/third_party/nsync/mu_semaphore_futex.c
+++ b/third_party/nsync/mu_semaphore_futex.c
@@ -21,7 +21,9 @@
 #include "libc/thread/thread.h"
 #include "third_party/nsync/atomic.h"
 #include "third_party/nsync/atomic.internal.h"
-#include "third_party/nsync/futex.internal.h"
+#include "libc/cosmo.h"
+#include "libc/calls/struct/timespec.h"
+#include "libc/cosmo.h"
 #include "third_party/nsync/mu_semaphore.internal.h"
 
 /**
@@ -61,7 +63,7 @@ errno_t nsync_mu_semaphore_p_futex (nsync_semaphore *s) {
 		i = ATM_LOAD ((nsync_atomic_uint32_ *) &f->i);
 		if (i == 0) {
 			int futex_result;
-			futex_result = -nsync_futex_wait_ (
+			futex_result = -cosmo_futex_wait (
 				(atomic_int *)&f->i, i,
 				PTHREAD_PROCESS_PRIVATE, 0, 0);
 			ASSERT (futex_result == 0 ||
@@ -100,9 +102,9 @@ errno_t nsync_mu_semaphore_p_with_deadline_futex (nsync_semaphore *s, int clock,
 				ts_buf.tv_nsec = NSYNC_TIME_NSEC (abs_deadline);
 				ts = &ts_buf;
 			}
-			futex_result = nsync_futex_wait_ ((atomic_int *)&f->i, i,
-							  PTHREAD_PROCESS_PRIVATE,
-							  clock, ts);
+			futex_result = cosmo_futex_wait ((atomic_int *)&f->i, i,
+							 PTHREAD_PROCESS_PRIVATE,
+							 clock, ts);
 			ASSERT (futex_result == 0 ||
 				futex_result == -EINTR ||
 				futex_result == -EAGAIN ||
@@ -136,5 +138,5 @@ void nsync_mu_semaphore_v_futex (nsync_semaphore *s) {
 		       (nsync_atomic_uint32_ *) &f->i, &old_value, old_value+1,
 		       memory_order_release, memory_order_relaxed)) {
 	}
-	ASSERT (nsync_futex_wake_ ((atomic_int *)&f->i, 1, PTHREAD_PROCESS_PRIVATE) >= 0);
+	ASSERT (cosmo_futex_wake ((atomic_int *)&f->i, 1, PTHREAD_PROCESS_PRIVATE) >= 0);
 }
diff --git a/third_party/openmp/kmp_lock.cpp b/third_party/openmp/kmp_lock.cpp
index cc7be24da..593d805b8 100644
--- a/third_party/openmp/kmp_lock.cpp
+++ b/third_party/openmp/kmp_lock.cpp
@@ -23,7 +23,7 @@
 
 #if KMP_USE_FUTEX
 #ifdef __COSMOPOLITAN__
-#include "third_party/nsync/futex.internal.h"
+#include <cosmo.h>
 #else
 #include <sys/syscall.h>
 #include <unistd.h>
@@ -380,7 +380,7 @@ __kmp_acquire_futex_lock_timed_template(kmp_futex_lock_t *lck, kmp_int32 gtid) {
 
     long rc;
 #ifdef __COSMOPOLITAN__
-    if ((rc = nsync_futex_wait_((int *)&(lck->lk.poll), poll_val, false, 0, NULL)) != 0) {
+    if ((rc = cosmo_futex_wait((int *)&(lck->lk.poll), poll_val, false, 0, NULL)) != 0) {
 #else
     if ((rc = syscall(__NR_futex, (int *)&(lck->lk.poll), FUTEX_WAIT, poll_val, NULL,
                       NULL, 0)) != 0) {
@@ -462,7 +462,7 @@ int __kmp_release_futex_lock(kmp_futex_lock_t *lck, kmp_int32 gtid) {
              ("__kmp_release_futex_lock: lck:%p, T#%d futex_wake 1 thread\n",
               lck, gtid));
 #ifdef __COSMOPOLITAN__
-    nsync_futex_wake_((int *)&(lck->lk.poll), 1, false);
+    cosmo_futex_wake((int *)&(lck->lk.poll), 1, false);
 #else
     syscall(__NR_futex, &(lck->lk.poll), FUTEX_WAKE, KMP_LOCK_BUSY(1, futex),
             NULL, NULL, 0);