cosmopolitan/libc/tinymath/rint.S

71 lines
2.8 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/nexgen32e/x86feature.h"
#include "libc/bits/smmintrin.h"
#include "libc/macros.h"
.source __FILE__
/ Rounds to nearest integer.
/
/ @param is double passed in %xmm0
/ @return double in %xmm0
/ @note rounding behavior can be changed in mxcsr
tinymath_rint:
#if !X86_NEED(SSE4_2)
testb X86_HAVE(SSE4_2)+kCpuids(%rip)
jz tinymath_rint$k8
.text.antiquity
tinymath_rint$k8:
0: movq %xmm0,%rax
movq %xmm0,%rdx
shr $52,%rdx
and $2047,%edx
cmp $1074,%edx
jg 2f
movsd mmm(%rip),%xmm1
shr $63,%rax
jne 3f
addsd %xmm1,%xmm0
subsd %xmm1,%xmm0
1: pxor %xmm2,%xmm2
ucomisd %xmm2,%xmm0
jp 2f
jne 2f
movsd sgn(%rip),%xmm0
test %rax,%rax
je 4f
2: ret
3: subsd %xmm1,%xmm0
addsd %xmm1,%xmm0
jmp 1b
4: pxor %xmm0,%xmm0
ret
.endfn tinymath_rint$k8,globl,hidden
.previous
.rodata.cst8
sgn: .quad 0x8000000000000000
mmm: .quad 0x4330000000000000
.previous
#endif
roundsd $_MM_FROUND_RINT,%xmm0,%xmm0
ret
.endfn tinymath_rint,globl
.alias tinymath_rint,rint