1/* ix87 specific frexp implementation for double.
2   Copyright (C) 1997, 2000 Free Software Foundation, Inc.
3   This file is part of the GNU C Library.
4   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
5
6   The GNU C Library is free software; you can redistribute it and/or
7   modify it under the terms of the GNU Lesser General Public
8   License as published by the Free Software Foundation; either
9   version 2.1 of the License, or (at your option) any later version.
10
11   The GNU C Library is distributed in the hope that it will be useful,
12   but WITHOUT ANY WARRANTY; without even the implied warranty of
13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14   Lesser General Public License for more details.
15
16   You should have received a copy of the GNU Lesser General Public
17   License along with the GNU C Library; if not, write to the Free
18   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
19   02111-1307 USA.  */
20
21#include <machine/asm.h>
22#include "bp-sym.h"
23#include "bp-asm.h"
24
25#ifdef __ELF__
26	.section .rodata
27#else
28	.text
29#endif
30
31	.align ALIGNARG(4)
32	ASM_TYPE_DIRECTIVE(two54,@object)
33two54:	.byte 0, 0, 0, 0, 0, 0, 0x50, 0x43
34	ASM_SIZE_DIRECTIVE(two54)
35
36#ifdef PIC
37#define MO(op) op##@GOTOFF(%edx)
38#else
39#define MO(op) op
40#endif
41
42#define PARMS	LINKAGE		/* no space for saved regs */
43#define VAL0	PARMS
44#define VAL1	VAL0+4
45#define EXPP	VAL1+4
46
47	.text
48ENTRY (BP_SYM (__frexp))
49	ENTER
50
51	movl	VAL0(%esp), %ecx
52	movl	VAL1(%esp), %eax
53	movl	%eax, %edx
54	andl	$0x7fffffff, %eax
55	orl	%eax, %ecx
56	jz	1f
57	xorl	%ecx, %ecx
58	cmpl	$0x7ff00000, %eax
59	jae	1f
60
61	cmpl	$0x00100000, %eax
62	jae	2f
63
64	fldl	VAL0(%esp)
65#ifdef	PIC
66	call	3f
673:	popl	%edx
68	addl	$_GLOBAL_OFFSET_TABLE_+[.-3b], %edx
69#endif
70	fmull	MO(two54)
71	movl	$-54, %ecx
72	fstpl	VAL0(%esp)
73	fwait
74	movl	VAL1(%esp), %eax
75	movl	%eax, %edx
76	andl	$0x7fffffff, %eax
77
782:	shrl	$20, %eax
79	andl	$0x800fffff, %edx
80	subl	$1022, %eax
81	orl	$0x3fe00000, %edx
82	addl	%eax, %ecx
83	movl	%edx, VAL1(%esp)
84
85	/* Store %ecx in the variable pointed to by the second argument,
86	   get the factor from the stack and return.  */
871:	movl	EXPP(%esp), %eax
88	CHECK_BOUNDS_BOTH_WIDE (%eax, EXPP(%esp), $4)
89	fldl	VAL0(%esp)
90	movl	%ecx, (%eax)
91
92	LEAVE
93	ret
94END (BP_SYM (__frexp))
95weak_alias (BP_SYM (__frexp), BP_SYM (frexp))
96