45 lines
2.7 KiB
ArmAsm
45 lines
2.7 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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│ This program is free software; you can redistribute it and/or modify │
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│ it under the terms of the GNU General Public License as published by │
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│ the Free Software Foundation; version 2 of the License. │
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│ │
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│ This program is distributed in the hope that it will be useful, but │
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│ WITHOUT ANY WARRANTY; without even the implied warranty of │
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│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │
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│ General Public License for more details. │
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│ │
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│ You should have received a copy of the GNU General Public License │
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│ along with this program; if not, write to the Free Software │
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│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
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│ 02110-1301 USA │
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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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