glibc/sysdeps/i386/fpu/s_frexpl.S
Ulrich Drepper 79569444ef Update.
2000-12-03  Ulrich Drepper  <drepper@redhat.com>

	* math/test-misc.c (main): Add tests for frexp.
	Reported by Fred J. Tydeman <tydeman@tybor.com>.
	* sysdeps/i386/fpu/s_frexpl.S: Don't overflow during the computation.
2000-12-03 10:00:46 +00:00

117 lines
2.7 KiB
ArmAsm

/* ix87 specific frexp implementation for long double.
Copyright (C) 1997, 2000 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 Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include <machine/asm.h>
#include "bp-sym.h"
#include "bp-asm.h"
#ifdef __ELF__
.section .rodata
#else
.text
#endif
.align ALIGNARG(4)
ASM_TYPE_DIRECTIVE(two64,@object)
two64: .byte 0, 0, 0, 0, 0, 0, 0xf0, 0x43
ASM_SIZE_DIRECTIVE(two64)
/* The following is LDBL_MAX / ldexp (1.0, 64), the largest
number we can handle the normal way. */
ASM_TYPE_DIRECTIVE(largest,@object)
largest:
.byte 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xbe, 0x7f, 0, 0
ASM_SIZE_DIRECTIVE(largest)
#ifdef PIC
#define MO(op) op##@GOTOFF(%edx)
#else
#define MO(op) op
#endif
#define PARMS LINKAGE /* no space for saved regs */
#define VAL0 PARMS
#define VAL1 VAL0+4
#define VAL2 VAL1+4
#define EXPP VAL2+4
.text
ENTRY (BP_SYM (__frexpl))
ENTER
movl VAL0(%esp), %ecx
movl VAL2(%esp), %eax
orl VAL1(%esp), %ecx
movl %eax, %edx
andl $0x7fff, %eax
orl %eax, %ecx
jz 1f
xorl %ecx, %ecx
cmpl $0x7fff, %eax
je 1f
cmpl $0, %eax
je 2f
cmpl $0x7fbe, %eax
ja 4f
fldt VAL0(%esp)
#ifdef PIC
call 3f
3: popl %edx
addl $_GLOBAL_OFFSET_TABLE_+[.-3b], %edx
#endif
fmull MO(two64) /* It's not necessary to use a 80bit factor */
movl $-64, %ecx
fstpt VAL0(%esp)
fwait
movl VAL2(%esp), %eax
movl %eax, %edx
andl $0x7fff, %eax
2: andl $0x8000, %edx
subl $16382, %eax
orl $0x3ffe, %edx
addl %eax, %ecx
movl %edx, VAL2(%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
CHECK_BOUNDS_BOTH_WIDE (%eax, EXPP(%esp), $4)
fldt VAL0(%esp)
movl %ecx, (%eax)
LEAVE
ret
4: movl VAL2(%esp), %ecx
movl %ecx, %edx
andl $0x7fff, %ecx
andl $0x8000, %edx
subl $16382, %ecx
orl $0x3ffe, %edx
movl %edx, VAL2(%esp)
jmp 1b
END (BP_SYM (__frexpl))
weak_alias (BP_SYM (__frexpl), BP_SYM (frexpl))