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/* ix87 specific frexp implementation for double.
Copyright (C) 1997-2019 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <machine/asm.h>
#include <libm-alias-double.h>
.section .rodata
.align ALIGNARG(4)
.type two54,@object
two54: .byte 0, 0, 0, 0, 0, 0, 0x50, 0x43
ASM_SIZE_DIRECTIVE(two54)
#ifdef PIC
#define MO(op) op##@GOTOFF(%edx)
#else
#define MO(op) op
#endif
#define PARMS 4 /* no space for saved regs */
#define VAL0 PARMS
#define VAL1 VAL0+4
#define EXPP VAL1+4
.text
ENTRY (__frexp)
movl VAL0(%esp), %ecx
movl VAL1(%esp), %eax
movl %eax, %edx
andl $0x7fffffff, %eax
orl %eax, %ecx
jz 1f
xorl %ecx, %ecx
cmpl $0x7ff00000, %eax
jae 1f
cmpl $0x00100000, %eax
jae 2f
fldl VAL0(%esp)
#ifdef PIC
LOAD_PIC_REG (dx)
#endif
fmull MO(two54)
movl $-54, %ecx
fstpl VAL0(%esp)
fwait
movl VAL1(%esp), %eax
movl %eax, %edx
andl $0x7fffffff, %eax
2: shrl $20, %eax
andl $0x800fffff, %edx
subl $1022, %eax
orl $0x3fe00000, %edx
addl %eax, %ecx
movl %edx, VAL1(%esp)
/* Store %ecx in the variable pointed to by the second argument,
get the factor from the stack and return. */
1: movl EXPP(%esp), %eax
fldl VAL0(%esp)
movl %ecx, (%eax)
ret
END (__frexp)
libm_alias_double (__frexp, frexp)
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