mirror of
https://github.com/jart/cosmopolitan.git
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6f7d0cb1c3
This makes breaking changes to add underscores to many non-standard function names provided by the c library. MODE=tiny is now tinier and we now use smaller locks that are better for tiny apps in this mode. Some headers have been renamed to be in the same folder as the build package, so it'll be easier to know which build dependency is needed. Certain old misguided interfaces have been removed. Intel intrinsics headers are now listed in libc/isystem (but not in the amalgamation) to help further improve open source compatibility. Header complexity has also been reduced. Lastly, more shell scripts are now available.
116 lines
4 KiB
C
116 lines
4 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2020 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above copyright notice and this permission notice appear in all copies. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/assert.h"
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#include "libc/intrin/bits.h"
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#include "libc/intrin/initializer.internal.h"
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#include "libc/intrin/safemacros.internal.h"
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#include "libc/calls/calls.h"
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#include "libc/calls/clock_gettime.internal.h"
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#include "libc/calls/state.internal.h"
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#include "libc/intrin/strace.internal.h"
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#include "libc/calls/syscall_support-sysv.internal.h"
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#include "libc/dce.h"
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#include "libc/macros.internal.h"
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#include "libc/nexgen32e/rdtsc.h"
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#include "libc/nexgen32e/x86feature.h"
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#include "libc/str/str.h"
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#include "libc/sysv/consts/clock.h"
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#include "libc/time/time.h"
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static clock_gettime_f *__gettime;
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static struct Now {
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uint64_t k0;
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long double r0, cpn;
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} g_now;
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static long double GetTimeSample(void) {
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uint64_t tick1, tick2;
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long double time1, time2;
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sched_yield();
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time1 = dtime(CLOCK_REALTIME_FAST);
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tick1 = rdtsc();
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nanosleep(&(struct timespec){0, 1000000}, NULL);
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time2 = dtime(CLOCK_REALTIME_FAST);
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tick2 = rdtsc();
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return (time2 - time1) * 1e9 / MAX(1, tick2 - tick1);
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}
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static long double MeasureNanosPerCycle(void) {
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bool tc;
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int i, n;
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long double avg, samp;
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tc = __time_critical;
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__time_critical = true;
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if (IsWindows()) {
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n = 10;
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} else {
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n = 5;
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}
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for (avg = 1.0L, i = 1; i < n; ++i) {
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samp = GetTimeSample();
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avg += (samp - avg) / i;
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}
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__time_critical = tc;
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STRACE("MeasureNanosPerCycle cpn*1000=%d", (long)(avg * 1000));
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return avg;
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}
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void RefreshTime(void) {
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struct Now now;
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now.cpn = MeasureNanosPerCycle();
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now.r0 = dtime(CLOCK_REALTIME_FAST);
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now.k0 = rdtsc();
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memcpy(&g_now, &now, sizeof(now));
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}
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static long double nowl_sys(void) {
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return dtime(CLOCK_REALTIME_FAST);
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}
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static long double nowl_art(void) {
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uint64_t ticks = rdtsc() - g_now.k0;
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return g_now.r0 + (1 / 1e9L * (ticks * g_now.cpn));
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}
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static long double nowl_vdso(void) {
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long double secs;
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struct timespec tv;
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assert(__gettime);
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__gettime(CLOCK_REALTIME_FAST, &tv);
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secs = tv.tv_nsec;
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secs *= 1 / 1e9L;
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secs += tv.tv_sec;
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return secs;
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}
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long double nowl_setup(void) {
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bool isfast;
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uint64_t ticks;
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__gettime = __clock_gettime_get(&isfast);
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if (isfast) {
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nowl = nowl_vdso;
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} else if (X86_HAVE(INVTSC)) {
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RefreshTime();
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nowl = nowl_art;
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} else {
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nowl = nowl_sys;
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}
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return nowl();
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}
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