This is a maintenance fork
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/*-*- 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/dce.h"
#include "libc/macros.h"
/ Forks process without copying page tables.
/
/ This is the same as fork() except it's optimized for the case
/ where the caller invokes exec() immediately afterwards.
/
/ @return pid of child process or 0 if forked process
/ @returnstwice
vfork: testb IsWindows()
jnz fork$nt
mov __NR_vfork(%rip),%eax
cmp $-1,%eax
je systemfive.enosys
pop %rsi
testb IsBsd()
jnz vfork.bsd
syscall
push %rsi
cmp $-4095,%rax
jae systemfive.error
ret
.endfn vfork,globl
vfork.bsd:
syscall
push %rsi
jc systemfive.errno
ret
.endfn vfork.bsd