mirror of
https://github.com/jart/cosmopolitan.git
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459 lines
16 KiB
ArmAsm
459 lines
16 KiB
ArmAsm
/*-*- mode:unix-assembly; indent-tabs-mode:t; tab-width:8; coding:utf-8 -*-│
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│vi: set et ft=asm ts=8 sw=8 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/dce.h"
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#include "libc/sysv/consts/prot.h"
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#include "libc/sysv/consts/nr.h"
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#include "libc/sysv/consts/map.h"
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#include "libc/macros.h"
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/* ▄▄▄
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▄▄▄ ▀▓▓▒▄
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▄▓▒▒░ ▀▓▒▒▒▄
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▄▓▓▓▒▀ ▄▄▄▄ ▒▓▒▒░▒▄
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▄▓▓▓▒▓ ▄▄▓██▓▓▓▓▒▒▒▒▓▓▄▄▓▓▒▒▒░░▒
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▓▓▓▓▒▒▒▄▄ ░▒█▓▓▓▓▓▓▓▓▓▒▒▒▒▒▒▒▒▒▒▒▓▒░░▒░
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██▓▓▓▒▒░░▒▒▒▒▓▓▓▓▓▓▒▓▒░▒▒░▀▒▒▒▒░▀░▒▒▒░▒
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▓▓▓▓▓▓▓▒▒▒▒▒▒▓▓▒▓▓▒▒▒░▒▒░░ ░▒▒░ ░▒▒▒▒
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▀▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▒▒░░▒░░ ░▒▒ ░ ▀▒▒
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▀▓▓█▓▓▓▓▓▓▓▓▓▓▒▒░░▒▒░░ ░░░▓░ ▓░░░▒
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▀▀█▓███▓▓▓▓▓▒▒░░░▒░░ ░█▓░█▓░█▓▓▄▒░
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░▓██▓▓▓▓▓▒▒░░░▒░░ ░████▓▒▓█▓▀░▀▄
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░▓██▓▓▓▓▓▒▒▒░░░▒░░ ▒██▓▒▒▒▒▒▒░░░▒
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████▓▓▓▓▓▒▒▒▒▒▒▒▒▒░░▒▓▓▒░░░░▒░░░▒░ ░░░░░
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░▓███▓▓▓▓▓▒▒░░░░░░░▒▒▒▒▒▒▒▒▒▒▒░░░ ░░░░░ ░
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▓███▓▓▓▓▓▒▓▒▒▒▒░░░░░░░░░▒▓▒▒░▀ ░░░ ░░░░░
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▀▒██▓▓▓▓▒▒▒▓▓▓▓▒▒▒▒▒▒▒▓▀▀░ ░░░░░░░░░ ░
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▓▓▓▓▓▓▓▒▓▒▒▒▒▓▓▓▒▀░ ░░░░░▄░░░ ░░░ ░░░░░░
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▓▓▓▒▒▒▒▒▒▒▒▒▒▒▓ █▓▒░░▒░░░░ ░░░░░░░░
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▄▓▓▓▒▒▒▒▒░░░░░░░▒▄▄▄░▒▓▓▒▒░▀░
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░▓█▓▓▒▒▒▒▒▒▒▒▒▒▒▒▒▒▓▓▓▓▓▓▒░░░▒ besiyata
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▓▓█▓▓▒▓▓▓▒▒▒░░░░░░▒▓▓▓▓▒▒▒▒▒░ dishmaya
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▓▓█▓▓▓▓▓▓▒▒▒░░░░░░░▒▓▓▒▀▀▀
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▓▓██▓▓▓▓▓▓▓▒▒▒▒▒▒▒▒▒▒▀
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▄▄▄░▒▓▓▓▓▓▓░▀▀ ▓▓▒░▓▒▒▒▒▒▒▒▒▒▒▄░░▀▀░░ ▄▄▄▄
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▄▄▄▒▒▓▓█▓▓▓▓▓▀▀▀▀▀ ▓▓▓▓▓▒▒▒▒▒▒▒▒▒▒▒▒▒▀░░▀░░▒▒▒░░░ ░░░░░
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▄▓▓▓▒▀▀ ▓▒▓▓▓▓▓▒▒▒▒▒▒▒▒▓░░░ ▒▒▒░░░░░░░░▒
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█▓▓▒ ▄▄▄ ▀▓▒▓▒▒▒▓▓▓▓▓▓▒▒▒░░░░░░░░░▒▒░░░░░░░
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▀▓▓▓▓▒▄▄▒▒▒▒▒▒▄▄ ▀▀▀▀░░▒▒▒▒░░░░░░
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▀▀▀▓▓▓▓▒▒▒▒▒▓▓▄▄
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╔────────────────────────────────────────────────────────────────────────────│─╗
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│ cosmopolitan § bell system five » system call support ─╬─│┼
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╚────────────────────────────────────────────────────────────────────────────│*/
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.initbss 300,_init_systemfive
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__hostos:
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.quad 0
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.endobj __hostos,globl,hidden
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// Performs System Five System Call.
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//
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// Cosmopolitan is designed to delegate all function calls into the
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// Linux, FreeBSD, OpenBSD, and XNU kernels via this function, with
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// few exceptions. This function should generally only be called by
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// generated thunks in the libc/sysv/syscalls/ directory.
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//
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// It's safe to call this function on Windows, where it will always
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// return -1 with errno == ENOSYS. Further note that -1 is the only
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// return value that means error, a common anti-pattern is to check
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// for values less than 0 (which is more problematic on 32-bit).
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//
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// It is important to consider that system calls are one order of a
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// magnitude more expensive than normal function calls. For example
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// getpid() on Linux usually takes 500ns, and cached i/o calls will
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// take 1µs or more. So we don't need to inline them like Chromium.
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//
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// Another thing to consider is that BSDs only loosely follow the
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// System Five ABI for the SYSCALL instruction. For example Linux
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// always follows the six argument limit but the FreeBSD sendfile
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// system call accepts a seventh argument that is passed on stack
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// and OpenBSD modifies functions like mmap so that the sixth arg
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// is passed on the stack. There's also the carry flag convention
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// that XNU, FreeBSD, and OpenBSD inherited from 386BSD aka Jolix
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//
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// @param %rax function ordinal supplied by jump slot
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// @param %rdi,%rsi,%rdx,%rcx,%r8,%r9 and rest on stack
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// @return %rax:%rdx is result, or -1 w/ errno on error
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// @clob %rcx,%r10,%r11
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// @see syscalls.sh
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__systemfive:
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.quad 0
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.endobj __systemfive,globl,hidden
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.previous
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.privileged
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.Lanchorpoint:
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#if SupportsLinux() || SupportsMetal()
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systemfive_linux:
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and $0xfff,%eax
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cmp $0xfff,%eax
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je systemfive_enosys
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mov %rcx,%r10 # syscall instruction clobbers %rcx
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push %rbp # linux never reads args from stack
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mov %rsp,%rbp # having frame will help backtraces
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syscall # this is known as a context switch
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pop %rbp # next we check to see if it failed
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cmp $-4095,%rax # system five nexgen32e abi § A.2.1
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jae systemfive_error # encodes errno as neg return value
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ret
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.endfn systemfive_linux,globl,hidden
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systemfive_error:
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neg %eax
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// 𝑠𝑙𝑖𝑑𝑒
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.endfn systemfive_error,globl,hidden
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#endif
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systemfive_errno:
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mov %eax,errno(%rip) # normalize to c library convention
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push $-1 # negative one is only error result
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pop %rax # the push pop is to save code size
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ret
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.endfn systemfive_errno,globl,hidden
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systemfive_enosys:
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mov ENOSYS(%rip),%eax
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jmp systemfive_errno
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.endfn systemfive_enosys,globl,hidden
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#if SupportsNetbsd()
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systemfive_netbsd:
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shr $4*13,%rax
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jmp systemfive_bsdscrub
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.endfn systemfive_netbsd,globl,hidden
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#endif
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#if SupportsOpenbsd()
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systemfive_openbsd:
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shr $4*10,%rax
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jmp systemfive_bsdscrub
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.endfn systemfive_openbsd,globl,hidden
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#endif
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#if SupportsFreebsd()
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systemfive_freebsd:
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shr $4*7,%rax
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movzwl %ax,%eax
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// 𝑠𝑙𝑖𝑑𝑒
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.endfn systemfive_freebsd,globl,hidden
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#endif
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#if SupportsBsd()
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systemfive_bsdscrub:
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and $0xfff,%eax
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// 𝑠𝑙𝑖𝑑𝑒
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.endfn systemfive_bsdscrub,globl,hidden
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systemfive_bsd:
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cmp $0xfff,%ax
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je systemfive_enosys
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mov %rcx,%r10 # note: we do not create a stack frame
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syscall # bsd will need arg on stack sometimes
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jc systemfive_errno # bsd sets carry flag if %rax is errno
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ret
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.endfn systemfive_bsd
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#endif
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#if SupportsXnu()
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systemfive_xnu:
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// 0x?????????2153??? # how syscalls.sh encodes xnu ordinals
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// │└┴┴┐
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// │ ├┬┐
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// 0x0000000002000153 # how xnu wants ordinals to be encoded
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mov %eax,%r11d
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and $0x0f000000,%r11d
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shl $8,%eax
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shr $20,%eax
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or %r11d,%eax
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jmp systemfive_bsd
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.endfn systemfive_xnu,globl,hidden
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#endif
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.previous
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// Initializes System Five system call support.
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//
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// (1) Extracts parameters passed by kernel
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// (2) Detects OS without issuing system calls
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// (3) Unpacks magnums from libc/sysv/consts.sh
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// (4) Replaces stack with one we control
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//
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// @param %r15 is auxv
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// @note OpenBSD devs: let us know if you start using auxv
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.init.start 300,_init_systemfive
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push %rbx
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push %rsi
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#if SupportsMetal()
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testb $METAL,(%rdi) # @see ape/ape.S
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jnz _init_systemfive_metal
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#endif
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#if SupportsXnu()
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testb $XNU,(%rdi) # @see libc/crt/crt.S
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jnz _init_systemfive_xnu
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#endif
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#if SupportsFreebsd()
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testb $FREEBSD,(%rdi) # @see libc/crt/crt.S
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jnz _init_systemfive_freebsd
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#endif
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#if SupportsWindows()
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testb $WINDOWS,(%rdi) # @see libc/runtime/winmain.c
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jnz _init_systemfive_windows
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#endif
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#if SupportsOpenbsd()
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cmpq $0,(%r15) # OpenBSD doesn't have auxv
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je _init_systemfive_openbsd
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#endif
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#if SupportsNetbsd()
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xor %eax,%eax
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0: cmpq $2014,(%r15,%rax,8) # NetBSD's distinctive AT_EXECFN
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je _init_systemfive_netbsd
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cmpq $0,(%r15,%rax,8)
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lea 2(%eax),%eax
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jnz 0b
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#endif
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#if SupportsLinux() || SupportsMetal()
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_init_systemfive_linux:
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pushb systemfive_linux-.Lanchorpoint
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push $LINUX
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ezlea syscon_linux,si
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jmp _init_systemfive_os
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#endif
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#if SupportsMetal()
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_init_systemfive_metal:
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pushb systemfive_linux-.Lanchorpoint
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push $METAL
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ezlea syscon_linux,si
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jmp _init_systemfive_os
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#endif
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#if SupportsWindows()
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_init_systemfive_windows:
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pushb systemfive_enosys-.Lanchorpoint
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push $WINDOWS
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ezlea syscon_windows,si
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jmp _init_systemfive_os
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#endif
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#if SupportsFreebsd()
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_init_systemfive_freebsd:
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pushb systemfive_freebsd-.Lanchorpoint
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push $FREEBSD
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ezlea syscon_freebsd,si
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jmp _init_systemfive_os
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#endif
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#if SupportsOpenbsd()
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_init_systemfive_openbsd:
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pushb systemfive_openbsd-.Lanchorpoint
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push $OPENBSD
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ezlea syscon_openbsd,si
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jmp _init_systemfive_os
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#endif
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#if SupportsNetbsd()
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_init_systemfive_netbsd:
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pushb systemfive_netbsd-.Lanchorpoint
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push $NETBSD
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ezlea syscon_netbsd,si
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jmp _init_systemfive_os
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#endif
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#if SupportsXnu()
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_init_systemfive_xnu:
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pushb systemfive_xnu-.Lanchorpoint
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push $XNU
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ezlea syscon_xnu,si
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// 𝑠𝑙𝑖𝑑𝑒
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#endif
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_init_systemfive_os:
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ezlea .Lanchorpoint,cx
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pop %rax
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stosq #→ __hostos
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pop %rax
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add %rcx,%rax
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stosq #→ __systemfive
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// 𝑠𝑙𝑖𝑑𝑒
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_init_systemfive_magnums:
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push %rdi
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ezlea syscon_start,di
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ezlea syscon_end,bx
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or $-1,%r9
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2: cmp %rbx,%rdi
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jnb 5f
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xor %ecx,%ecx
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xor %edx,%edx
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3: lodsb # decodes sleb128
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mov %rax,%r8
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and $127,%r8d
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sal %cl,%r8
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add $7,%ecx
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or %r8,%rdx
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test %al,%al
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js 3b
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test $64,%al
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je 4f
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mov %r9,%rax
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sal %cl,%rax
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or %rax,%rdx
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4: mov %rdx,%rax
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cmpq $0,(%rdi) # dont change if set
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cmovne (%rdi),%rax # @see WinMain()
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stosq
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jmp 2b
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5: pop %rdi
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pop %rsi
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pop %rbx
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// 𝑠𝑙𝑖𝑑𝑒
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#if SupportsSystemv() && !defined(TINY)
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_init_systemfive_stack: # determinism ftw!
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#if SupportsWindows()
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testb IsWindows() # already did this
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jnz _init_systemfive_done
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#endif
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push %rdi
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push %rsi
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mov __NR_mmap,%eax
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mov $0x700000000000-STACKSIZE,%rdi
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mov $STACKSIZE,%esi
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mov $PROT_READ|PROT_WRITE,%edx
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mov $MAP_PRIVATE|MAP_FIXED,%r10d
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or MAP_ANONYMOUS,%r10d
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or $-1,%r8d
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xor %r9d,%r9d
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push %r9 # openbsd:pad
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push %r9 # openbsd:align
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#if SupportsOpenbsd()
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testb IsOpenbsd()
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jz 0f
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syscall # openbsd:dubstack
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jc 1f
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mov __NR_mmap,%eax
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#endif
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0: or MAP_GROWSDOWN,%r10d # openbsd:mapstack
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clc
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syscall
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pop %r9
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pop %r9
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jnc 2f
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1: mov %eax,%edi
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mov __NR_exit_group,%eax
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syscall
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2: test %rax,%rax
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js 1b
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.weak _mmi
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ezlea _mmi,cx
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test %rcx,%rcx
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jz 3f
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movb $1,(%rcx) # _mmi.i
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movl $(0x700000000000-STACKSIZE)>>16,8(%rcx) # _mmi.p[0].x
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movl $(0x700000000000-1)>>16,12(%rcx) # _mmi.p[0].y
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mov %edx,20(%rcx) # _mmi.p[0].prot
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mov %r10d,24(%rcx) # _mmi.p[0].flags
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3: pop %rsi
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pop %rdi
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leave
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pop %rcx
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lea STACKSIZE-16(%rax),%rsp # openbsd:stackbound
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mov %rbp,(%rsp)
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push %rcx
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push %rbp
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mov %rsp,%rbp
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// 𝑠𝑙𝑖𝑑𝑒
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_init_systemfive_syscall:
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mov __NR_msyscall,%eax # syscall origin protect
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test %eax,%eax # openbsd is pretty cool
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js _init_systemfive_done
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push %rdi
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push %rsi
|
||
.weak __privileged_addr
|
||
.weak __privileged_size
|
||
mov $__privileged_addr,%edi
|
||
mov $__privileged_size,%esi
|
||
syscall
|
||
pop %rsi
|
||
pop %rdi
|
||
// 𝑠𝑙𝑖𝑑𝑒
|
||
#endif /* TINY */
|
||
_init_systemfive_done:
|
||
nop
|
||
.init.end 300,_init_systemfive,globl,hidden
|
||
|
||
// Sections for varint encoded magic numbers.
|
||
//
|
||
// These sections are all ordered by (group_name, constant_name).
|
||
// They're populated by modules simply referencing the symbols.
|
||
//
|
||
// @see libc/sysv/consts.sh
|
||
// @see libc/sysv/consts/syscon_h
|
||
.section .piro.bss.sort.syscon.1,"aw",@nobits
|
||
.align 8
|
||
syscon_start:/*
|
||
...decentralized quadwords...
|
||
*/.previous
|
||
.section .piro.bss.sort.syscon.3,"aw",@nobits
|
||
syscon_end:
|
||
.previous
|
||
.type syscon_start,@object
|
||
.type syscon_end,@object
|
||
.globl syscon_start
|
||
.globl syscon_end
|
||
#if SupportsLinux() || SupportsMetal()
|
||
.section .sort.rodata.syscon.linux.1,"a",@progbits
|
||
.align 1
|
||
syscon_linux:/*
|
||
...decentralized leb128...
|
||
*/.previous
|
||
.type syscon_linux,@object
|
||
.globl syscon_linux
|
||
#endif
|
||
#if SupportsXnu()
|
||
.section .sort.rodata.syscon.xnu.1,"a",@progbits
|
||
.align 1
|
||
syscon_xnu:/*
|
||
...decentralized leb128...
|
||
*/.previous
|
||
.type syscon_xnu,@object
|
||
.globl syscon_xnu
|
||
#endif
|
||
#if SupportsFreebsd()
|
||
.section .sort.rodata.syscon.freebsd.1,"a",@progbits
|
||
.align 1
|
||
syscon_freebsd:/*
|
||
...decentralized leb128...
|
||
*/.previous
|
||
.type syscon_freebsd,@object
|
||
.globl syscon_freebsd
|
||
#endif
|
||
#if SupportsOpenbsd()
|
||
.section .sort.rodata.syscon.openbsd.1,"a",@progbits
|
||
.align 1
|
||
syscon_openbsd:/*
|
||
...decentralized leb128...
|
||
*/.previous
|
||
.type syscon_openbsd,@object
|
||
.globl syscon_openbsd
|
||
#endif
|
||
#if SupportsNetbsd()
|
||
.section .sort.rodata.syscon.netbsd.1,"a",@progbits
|
||
.align 1
|
||
syscon_netbsd:/*
|
||
...decentralized leb128...
|
||
*/.previous
|
||
.type syscon_netbsd,@object
|
||
.globl syscon_netbsd
|
||
#endif
|
||
#if SupportsWindows()
|
||
.section .sort.rodata.syscon.windows.1,"a",@progbits
|
||
.align 1
|
||
syscon_windows:/*
|
||
...decentralized leb128...
|
||
*/.previous
|
||
.type syscon_windows,@object
|
||
.globl syscon_windows
|
||
#endif
|