1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
|
/*
* Written by J.T. Conklin <jtc@netbsd.org>.
* Public domain.
*
* Correct handling of y==-inf <drepper@gnu>
*/
#include <machine/asm.h>
RCSID("$NetBSD: e_scalb.S,v 1.4 1995/05/08 23:49:52 jtc Exp $")
#ifdef __ELF__
.section .rodata
#else
.text
#endif
.align ALIGNARG(4)
ASM_TYPE_DIRECTIVE(zero_nan,@object)
zero_nan:
.double 0.0
nan: .byte 0, 0, 0, 0, 0, 0, 0xff, 0x7f
minus_zero:
.byte 0, 0, 0, 0, 0, 0, 0, 0x80
.byte 0, 0, 0, 0, 0, 0, 0xff, 0x7f
ASM_SIZE_DIRECTIVE(zero_nan)
#ifdef PIC
#define MO(op) op##@GOTOFF(%ecx)
#define MOX(op,x,f) op##@GOTOFF(%ecx,x,f)
#else
#define MO(op) op
#define MOX(op,x,f) op(,x,f)
#endif
.text
ENTRY(__ieee754_scalb)
fldl 12(%esp)
fxam
fnstsw
fldl 4(%esp)
andl $0x4700, %eax
cmpl $0x0700, %eax
je 1f
andl $0x4500, %eax
cmpl $0x0100, %eax
je 2f
fxam
fnstsw
andl $0x4500, %eax
cmpl $0x0100, %eax
je 3f
fld %st(1)
frndint
fcomp %st(2)
fnstsw
sahf
jne 4f
fscale
fstp %st(1)
ret
/* y is -inf */
1: fxam
#ifdef PIC
call 1f
1: popl %ecx
addl $_GLOBAL_OFFSET_TABLE_+[.-1b], %ecx
#endif
fnstsw
movl 8(%esp), %edx
shrl $5, %eax
fstp %st
fstp %st
andl $0x80000000, %edx
andl $8, %eax
jnz 4f
shrl $27, %edx
addl %edx, %eax
fldl MOX(zero_nan, %eax, 1)
ret
/* The result is NaN, but we must not raise an exception.
So use a variable. */
2: fstp %st
fstp %st
#ifdef PIC
call 1f
1: popl %ecx
addl $_GLOBAL_OFFSET_TABLE_+[.-1b], %ecx
#endif
fldl MO(nan)
ret
/* The first parameter is a NaN. Return it. */
3: fstp %st(1)
ret
/* Return NaN and raise the invalid exception. */
4: fstp %st
fstp %st
fldz
fdiv %st
ret
END(__ieee754_scalb)
|
