44 lines
2.6 KiB
ArmAsm
44 lines
2.6 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 tw=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/macros.h"
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.source __FILE__
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/ Performs raw System Five system call.
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/
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/ This function provides a direct path into system call support
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/ that's friendly to C code, since it doesn't need an intermediate
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/ thunk. It only supports arities up to six, since there's no way
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/ to do more safely; this isn't a problem with Linux, although
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/ certain BSD calls may not be available.
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/
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/ @param %rdi is system call ordinal, which isn't translated,
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/ and must be correct for the underlying host system
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/ @param %rsi,%rdx,%rcx,%r8,%r9 may supply parameters 1 through 5
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/ @param sixth is optionally pushed on the stack before call
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/ @return %rax has result, or -1 w/ errno on failure
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syscall:mov %rdi,%rax
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mov %rsi,%rdi
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mov %rdx,%rsi
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mov %rcx,%rdx
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mov %r8,%rcx # ← intended
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mov %r9,%r8
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mov 8(%rsp),%r9
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jmp *__systemfive(%rip)
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.endfn syscall,globl
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