Files
cosmopolitan/libc/calls/getntsyspath.S

55 lines
2.7 KiB
ArmAsm

/*-*- mode:unix-assembly; indent-tabs-mode:t; tab-width:8; coding:utf-8 -*-│
│vi: set et ft=asm ts=8 tw=8 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/macros.internal.h"
.source __FILE__
// Obtains WIN32 magic path, e.g. GetTempPathA.
//
// @param rax is address of ANSI path provider function
// @param rdi is output buffer
// @param rdx is output buffer size in bytes that's >0
// @return eax is string length w/ NUL that's ≤ edx
// @return rdi is rdi+edx
.text.startup
__getntsyspath:
push %rbp
mov %rsp,%rbp
push %rdx
movpp %rdi,%rcx # call f=%rax(p1=%rcx,p2=%rdx)
sub $40,%rsp
call *%rax
xor %edx,%edx
mov -8(%rbp),%ecx # restore %edx param as %ecx
cmp %eax,%ecx # use current dir on overflow
cmovbe %edx,%eax
cmp $1,%eax # leave empty strings empty
jbe 1f
cmpb $'\\',-1(%rdi,%rax) # guarantee trailing slash
je 1f
movw $'\\',(%rdi,%rax)
inc %eax
1: inc %rdi # change backslash to slash
cmpb $'\\',-1(%rdi)
jne 2f
movb $'/',-1(%rdi)
2: .loop 1b
leave
ret
.endfn __getntsyspath,globl,hidden