cosmopolitan/libc/bits/bcxcpy.S

55 lines
2.4 KiB
ArmAsm

/*-*- mode:unix-assembly; indent-tabs-mode:t; tab-width:8; coding:utf-8 -*-│
vi: set et ft=asm ts=8 sw=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"
bcxcpy: push %rbp
mov %rsp,%rbp
.profilable
push %rbx
xor %ebx,%ebx
lea -64(%rbp),%rdx
sub $24,%rsp
3: lea (,%rbx,4),%ecx
mov %rsi,%rax
shr %cl,%rax
and $15,%eax
cmp $9,%eax
lea 7(%rax),%ecx
cmova %ecx,%eax
add $48,%eax
mov %al,(%rdx,%rbx)
add $1,%rbx
cmp $16,%rbx
jne 3b
mov %rdx,%rax
lea -48(%rbp),%rcx
lea 15(%rdi),%rdx
4: movzbl (%rax),%ebx
add $1,%rax
sub $1,%rdx
mov %bl,1(%rdx)
cmp %rcx,%rax
jne 4b
add $24,%rsp
pop %rbx
pop %rbp
ret
.endfn bcxcpy,globl