summaryrefslogtreecommitdiff
path: root/src/math/i386/exp_ld.s
blob: 99cba01fa172ffb7425142b2c3c773ae328c17fc (plain) (blame)
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
.global expm1l
.type expm1l,@function
expm1l:
	fldt 4(%esp)
	fldl2e
	fmulp
	mov $0xc2820000,%eax
	push %eax
	flds (%esp)
	pop %eax
	fucomp %st(1)
	fnstsw %ax
	sahf
	fld1
	jb 1f
		# x*log2e < -65, return -1 without underflow
	fstp %st(1)
	fchs
	ret
1:	fld %st(1)
	fabs
	fucom %st(1)
	fnstsw %ax
	fstp %st(0)
	fstp %st(0)
	sahf
	ja 1f
	f2xm1
	ret
1:	call 1f
	fld1
	fsubrp
	ret

.global exp2l
.global __exp2l
.hidden __exp2l
.type exp2l,@function
exp2l:
__exp2l:
	fldt 4(%esp)
1:	sub $12,%esp
	fld %st(0)
	fstpt (%esp)
	mov 8(%esp),%ax
	and $0x7fff,%ax
	cmp $0x3fff+13,%ax
	jb 4f             # |x| < 8192
	cmp $0x3fff+15,%ax
	jae 3f            # |x| >= 32768
	fsts (%esp)
	cmpl $0xc67ff800,(%esp)
	jb 2f             # x > -16382
	movl $0x5f000000,(%esp)
	flds (%esp)       # 0x1p63
	fld %st(1)
	fsub %st(1)
	faddp
	fucomp %st(1)
	fnstsw
	sahf
	je 2f             # x - 0x1p63 + 0x1p63 == x
	movl $1,(%esp)
	flds (%esp)       # 0x1p-149
	fdiv %st(1)
	fstps (%esp)      # raise underflow
2:	fld1
	fld %st(1)
	frndint
	fxch %st(2)
	fsub %st(2)       # st(0)=x-rint(x), st(1)=1, st(2)=rint(x)
	f2xm1
	faddp             # 2^(x-rint(x))
1:	fscale
	fstp %st(1)
	add $12,%esp
	ret
3:	xor %eax,%eax
4:	cmp $0x3fff-64,%ax
	fld1
	jb 1b             # |x| < 0x1p-64
	fstpt (%esp)
	fistl 8(%esp)
	fildl 8(%esp)
	fsubrp %st(1)
	addl $0x3fff,8(%esp)
	f2xm1
	fld1
	faddp             # 2^(x-rint(x))
	fldt (%esp)       # 2^rint(x)
	fmulp
	add $12,%esp
	ret