cosmopolitan/libc/tinymath/frexp.S
Justine Tunney fdc3fa9148 Remove sun musl fdlibm math library
The libm code from musl wasn't being used since most of these functions
are implemented using x87 which goes faster than a library intended for
risc machines.
2021-01-31 18:25:16 -08:00

58 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 tw=8 fenc=utf-8 :vi
Copyright 2020 Justine Alexandra Roberts Tunney
Permission to use, copy, modify, and/or distribute this software for
any purpose with or without fee is hereby granted, provided that the
above copyright notice and this permission notice appear in all copies.
THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE
AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
PERFORMANCE OF THIS SOFTWARE.
*/
#include "libc/macros.h"
.source __FILE__
frexp: .leafprologue
push %rbx
push %rdx
mov %rdi,%rbx
movq %xmm0,%rax
shr $52,%rax
and $0x7ff,%eax
jne 3f
xorps %xmm1,%xmm1
ucomisd %xmm1,%xmm0
jp 1f
je 2f
1: mulsd 6f(%rip),%xmm0
mov %rbx,%rdi
call frexp
subl $64,(%rbx)
jmp 5f
2: movl $0,(%rdi)
jmp 5f
3: cmp $0x7ff,%eax
je 5f
movq %xmm0,%rdx
sub $0x3fe,%eax
mov %eax,(%rdi)
movabs $-9218868437227405313,%rax
and %rax,%rdx
mov $511,%eax
sal $53,%rax
or %rax,%rdx
movq %rdx,%xmm0
5: pop %rax
pop %rbx
.leafepilogue
.endfn frexp,globl
.rodata.cst8
6: .long 0,0x43f00000