cosmopolitan/libc/bits/i2bcd.S

49 lines
2.3 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"
/ Converts integer to binary-coded decimal.
i2bcd: .leafprologue
.profilable
test %rdi,%rdi
je 2f
mov %rdi,%rsi
xor %r9d,%r9d
mov $0xcccccccccccccccd,%r8
xor %ecx,%ecx
1: mov %rsi,%rax
mul %r8
shr $3,%rdx
lea (%rdx,%rdx),%rax
lea (%rax,%rax,4),%rax
mov %rsi,%rdi
sub %rax,%rdi
shl %cl,%rdi
add %rdi,%r9
add $4,%rcx
cmp $9,%rsi
mov %rdx,%rsi
ja 1b
jmp 3f
2: xor %r9d,%r9d
3: mov %r9,%rax
.leafepilogue
.endfn i2bcd,globl