55 lines
2.6 KiB
ArmAsm
55 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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/ Obtains WIN32 magic path, e.g. GetTempPathA.
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/
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/ @param rax is address of ANSI path provider function
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/ @param rdi is output buffer
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/ @param rdx is output buffer size in bytes that's >0
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/ @return eax is string length w/ NUL that's ≤ edx
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/ @return rdi is rdi+edx
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.text.startup
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__getntsyspath:
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push %rbp
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mov %rsp,%rbp
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push %rdx
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movpp %rdi,%rcx # call f=%rax(p1=%rcx,p2=%rdx)
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sub $40,%rsp
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call *%rax
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xor %edx,%edx
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mov -8(%rbp),%ecx # restore %edx param as %ecx
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cmp %eax,%ecx # use current dir on overflow
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cmovbe %edx,%eax
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cmp $1,%eax # leave empty strings empty
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jbe 1f
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cmpb $'\\,-1(%rdi,%rax) # guarantee trailing slash
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je 1f
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movw $'\\,(%rdi,%rax)
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inc %eax
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1: inc %rdi # change backslash to slash
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cmpb $'\\,-1(%rdi)
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jne 2f
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movb $'/,-1(%rdi)
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2: .loop 1b
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leave
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ret
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.endfn __getntsyspath,globl,hidden
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