Text file
src/math/log1p_s390x.s
Documentation: math
1// Copyright 2017 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5#include "textflag.h"
6
7// Constants
8DATA ·log1pxlim<> + 0(SB)/4, $0xfff00000
9GLOBL ·log1pxlim<> + 0(SB), RODATA, $4
10DATA ·log1pxzero<> + 0(SB)/8, $0.0
11GLOBL ·log1pxzero<> + 0(SB), RODATA, $8
12DATA ·log1pxminf<> + 0(SB)/8, $0xfff0000000000000
13GLOBL ·log1pxminf<> + 0(SB), RODATA, $8
14DATA ·log1pxnan<> + 0(SB)/8, $0x7ff8000000000000
15GLOBL ·log1pxnan<> + 0(SB), RODATA, $8
16DATA ·log1pyout<> + 0(SB)/8, $0x40fce621e71da000
17GLOBL ·log1pyout<> + 0(SB), RODATA, $8
18DATA ·log1pxout<> + 0(SB)/8, $0x40f1000000000000
19GLOBL ·log1pxout<> + 0(SB), RODATA, $8
20DATA ·log1pxl2<> + 0(SB)/8, $0xbfda7aecbeba4e46
21GLOBL ·log1pxl2<> + 0(SB), RODATA, $8
22DATA ·log1pxl1<> + 0(SB)/8, $0x3ffacde700000000
23GLOBL ·log1pxl1<> + 0(SB), RODATA, $8
24DATA ·log1pxa<> + 0(SB)/8, $5.5
25GLOBL ·log1pxa<> + 0(SB), RODATA, $8
26DATA ·log1pxmone<> + 0(SB)/8, $-1.0
27GLOBL ·log1pxmone<> + 0(SB), RODATA, $8
28
29// Minimax polynomial approximations
30DATA ·log1pc8<> + 0(SB)/8, $0.212881813645679599E-07
31GLOBL ·log1pc8<> + 0(SB), RODATA, $8
32DATA ·log1pc7<> + 0(SB)/8, $-.148682720127920854E-06
33GLOBL ·log1pc7<> + 0(SB), RODATA, $8
34DATA ·log1pc6<> + 0(SB)/8, $0.938370938292558173E-06
35GLOBL ·log1pc6<> + 0(SB), RODATA, $8
36DATA ·log1pc5<> + 0(SB)/8, $-.602107458843052029E-05
37GLOBL ·log1pc5<> + 0(SB), RODATA, $8
38DATA ·log1pc4<> + 0(SB)/8, $0.397389654305194527E-04
39GLOBL ·log1pc4<> + 0(SB), RODATA, $8
40DATA ·log1pc3<> + 0(SB)/8, $-.273205381970859341E-03
41GLOBL ·log1pc3<> + 0(SB), RODATA, $8
42DATA ·log1pc2<> + 0(SB)/8, $0.200350613573012186E-02
43GLOBL ·log1pc2<> + 0(SB), RODATA, $8
44DATA ·log1pc1<> + 0(SB)/8, $-.165289256198351540E-01
45GLOBL ·log1pc1<> + 0(SB), RODATA, $8
46DATA ·log1pc0<> + 0(SB)/8, $0.181818181818181826E+00
47GLOBL ·log1pc0<> + 0(SB), RODATA, $8
48
49
50// Table of log10 correction terms
51DATA ·log1ptab<> + 0(SB)/8, $0.585235384085551248E-01
52DATA ·log1ptab<> + 8(SB)/8, $0.412206153771168640E-01
53DATA ·log1ptab<> + 16(SB)/8, $0.273839003221648339E-01
54DATA ·log1ptab<> + 24(SB)/8, $0.166383778368856480E-01
55DATA ·log1ptab<> + 32(SB)/8, $0.866678223433169637E-02
56DATA ·log1ptab<> + 40(SB)/8, $0.319831684989627514E-02
57DATA ·log1ptab<> + 48(SB)/8, $-.000000000000000000E+00
58DATA ·log1ptab<> + 56(SB)/8, $-.113006378583725549E-02
59DATA ·log1ptab<> + 64(SB)/8, $-.367979419636602491E-03
60DATA ·log1ptab<> + 72(SB)/8, $0.213172484510484979E-02
61DATA ·log1ptab<> + 80(SB)/8, $0.623271047682013536E-02
62DATA ·log1ptab<> + 88(SB)/8, $0.118140812789696885E-01
63DATA ·log1ptab<> + 96(SB)/8, $0.187681358930914206E-01
64DATA ·log1ptab<> + 104(SB)/8, $0.269985148668178992E-01
65DATA ·log1ptab<> + 112(SB)/8, $0.364186619761331328E-01
66DATA ·log1ptab<> + 120(SB)/8, $0.469505379381388441E-01
67GLOBL ·log1ptab<> + 0(SB), RODATA, $128
68
69// Log1p returns the natural logarithm of 1 plus its argument x.
70// It is more accurate than Log(1 + x) when x is near zero.
71//
72// Special cases are:
73// Log1p(+Inf) = +Inf
74// Log1p(±0) = ±0
75// Log1p(-1) = -Inf
76// Log1p(x < -1) = NaN
77// Log1p(NaN) = NaN
78// The algorithm used is minimax polynomial approximation
79// with coefficients determined with a Remez exchange algorithm.
80
81TEXT ·log1pAsm(SB), NOSPLIT, $0-16
82 FMOVD x+0(FP), F0
83 MOVD $·log1pxmone<>+0(SB), R1
84 MOVD ·log1pxout<>+0(SB), R2
85 FMOVD 0(R1), F3
86 MOVD $·log1pxa<>+0(SB), R1
87 MOVWZ ·log1pxlim<>+0(SB), R0
88 FMOVD 0(R1), F1
89 MOVD $·log1pc8<>+0(SB), R1
90 FMOVD 0(R1), F5
91 MOVD $·log1pc7<>+0(SB), R1
92 VLEG $0, 0(R1), V20
93 MOVD $·log1pc6<>+0(SB), R1
94 WFSDB V0, V3, V4
95 VLEG $0, 0(R1), V18
96 MOVD $·log1pc5<>+0(SB), R1
97 VLEG $0, 0(R1), V16
98 MOVD R2, R5
99 LGDR F4, R3
100 WORD $0xC0190006 //iilf %r1,425983
101 BYTE $0x7F
102 BYTE $0xFF
103 SRAD $32, R3, R3
104 SUBW R3, R1
105 SRW $16, R1, R1
106 BYTE $0x18 //lr %r4,%r1
107 BYTE $0x41
108 RISBGN $0, $15, $48, R4, R2
109 RISBGN $16, $31, $32, R4, R5
110 MOVW R0, R6
111 MOVW R3, R7
112 CMPBGT R6, R7, L8
113 WFCEDBS V4, V4, V6
114 MOVD $·log1pxzero<>+0(SB), R1
115 FMOVD 0(R1), F2
116 BVS LEXITTAGlog1p
117 WORD $0xB3130044 // lcdbr %f4,%f4
118 WFCEDBS V2, V4, V6
119 BEQ L9
120 WFCHDBS V4, V2, V2
121 BEQ LEXITTAGlog1p
122 MOVD $·log1pxnan<>+0(SB), R1
123 FMOVD 0(R1), F0
124 FMOVD F0, ret+8(FP)
125 RET
126
127L8:
128 LDGR R2, F2
129 FSUB F4, F3
130 FMADD F2, F4, F1
131 MOVD $·log1pc4<>+0(SB), R2
132 WORD $0xB3130041 // lcdbr %f4,%f1
133 FMOVD 0(R2), F7
134 FSUB F3, F0
135 MOVD $·log1pc3<>+0(SB), R2
136 FMOVD 0(R2), F3
137 MOVD $·log1pc2<>+0(SB), R2
138 WFMDB V1, V1, V6
139 FMADD F7, F4, F3
140 WFMSDB V0, V2, V1, V0
141 FMOVD 0(R2), F7
142 WFMADB V4, V5, V20, V5
143 MOVD $·log1pc1<>+0(SB), R2
144 FMOVD 0(R2), F2
145 FMADD F7, F4, F2
146 WFMADB V4, V18, V16, V4
147 FMADD F3, F6, F2
148 WFMADB V5, V6, V4, V5
149 FMUL F6, F6
150 MOVD $·log1pc0<>+0(SB), R2
151 WFMADB V6, V5, V2, V6
152 FMOVD 0(R2), F4
153 WFMADB V0, V6, V4, V6
154 RISBGZ $57, $60, $3, R1, R1
155 MOVD $·log1ptab<>+0(SB), R2
156 MOVD $·log1pxl1<>+0(SB), R3
157 WORD $0x68112000 //ld %f1,0(%r1,%r2)
158 FMOVD 0(R3), F2
159 WFMADB V0, V6, V1, V0
160 MOVD $·log1pyout<>+0(SB), R1
161 LDGR R5, F6
162 FMOVD 0(R1), F4
163 WFMSDB V2, V6, V4, V2
164 MOVD $·log1pxl2<>+0(SB), R1
165 FMOVD 0(R1), F4
166 FMADD F4, F2, F0
167 FMOVD F0, ret+8(FP)
168 RET
169
170L9:
171 MOVD $·log1pxminf<>+0(SB), R1
172 FMOVD 0(R1), F0
173 FMOVD F0, ret+8(FP)
174 RET
175
176
177LEXITTAGlog1p:
178 FMOVD F0, ret+8(FP)
179 RET
180
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