cosmopolitan/libc/calls/getntsyspath.S

56 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
This program is free software; you can redistribute it and/or modify │
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License. │
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of │
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software │
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA
*/
#include "libc/macros.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