1/* Function logf vectorized with AVX2.
2 Copyright (C) 2014-2024 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19#include <sysdep.h>
20#include "svml_s_logf_data.h"
21
22 .section .text.avx2, "ax", @progbits
23ENTRY(_ZGVdN8v_logf_avx2)
24/*
25 ALGORITHM DESCRIPTION:
26
27 log(x) = exponent_x*log(2) + log(mantissa_x), if mantissa_x<4/3
28 log(x) = (exponent_x+1)*log(2) + log(0.5*mantissa_x), if mantissa_x>4/3
29
30 R = mantissa_x - 1, if mantissa_x<4/3
31 R = 0.5*mantissa_x - 1, if mantissa_x>4/3
32 |R|< 1/3
33
34 log(1+R) is approximated as a polynomial: degree 9 for 1-ulp,
35 degree 7 for 4-ulp, degree 3 for half-precision. */
36
37 pushq %rbp
38 cfi_adjust_cfa_offset (8)
39 cfi_rel_offset (%rbp, 0)
40 movq %rsp, %rbp
41 cfi_def_cfa_register (%rbp)
42 andq $-64, %rsp
43 subq $448, %rsp
44 movq __svml_slog_data@GOTPCREL(%rip), %rax
45 vmovaps %ymm0, %ymm2
46 vmovups _iBrkValue(%rax), %ymm6
47 vmovups _iLoRange(%rax), %ymm1
48/* check for working range,
49 set special argument mask (denormals/zero/Inf/NaN) */
50 vpaddd _iHiDelta(%rax), %ymm2, %ymm7
51
52/* reduction: compute r,n */
53 vpsubd %ymm6, %ymm2, %ymm4
54
55/* exponent_x (mantissa_x<4/3) or exponent_x+1 (mantissa_x>4/3) */
56 vpsrad $23, %ymm4, %ymm3
57 vpand _iOffExpoMask(%rax), %ymm4, %ymm5
58 vmovups _sPoly_7(%rax), %ymm4
59 vcvtdq2ps %ymm3, %ymm0
60
61/* mantissa_x (mantissa_x<4/3), or 0.5*mantissa_x (mantissa_x>4/3) */
62 vpaddd %ymm6, %ymm5, %ymm3
63
64/* reduced argument R */
65 vsubps _sOne(%rax), %ymm3, %ymm5
66
67/* polynomial evaluation starts here */
68 vfmadd213ps _sPoly_6(%rax), %ymm5, %ymm4
69 vfmadd213ps _sPoly_5(%rax), %ymm5, %ymm4
70 vfmadd213ps _sPoly_4(%rax), %ymm5, %ymm4
71 vfmadd213ps _sPoly_3(%rax), %ymm5, %ymm4
72 vfmadd213ps _sPoly_2(%rax), %ymm5, %ymm4
73 vfmadd213ps _sPoly_1(%rax), %ymm5, %ymm4
74 vmulps %ymm5, %ymm4, %ymm6
75
76/* polynomial evaluation end */
77 vfmadd213ps %ymm5, %ymm5, %ymm6
78 vpcmpgtd %ymm7, %ymm1, %ymm1
79 vmovmskps %ymm1, %ecx
80
81/* final reconstruction:
82 add exponent_value*log2 to polynomial result */
83 vfmadd132ps _sLn2(%rax), %ymm6, %ymm0
84 testl %ecx, %ecx
85 jne .LBL_1_3
86
87.LBL_1_2:
88 cfi_remember_state
89 movq %rbp, %rsp
90 cfi_def_cfa_register (%rsp)
91 popq %rbp
92 cfi_adjust_cfa_offset (-8)
93 cfi_restore (%rbp)
94 ret
95
96.LBL_1_3:
97 cfi_restore_state
98 vmovups %ymm2, 320(%rsp)
99 vmovups %ymm0, 384(%rsp)
100 je .LBL_1_2
101
102 xorb %dl, %dl
103 xorl %eax, %eax
104 vmovups %ymm8, 224(%rsp)
105 vmovups %ymm9, 192(%rsp)
106 vmovups %ymm10, 160(%rsp)
107 vmovups %ymm11, 128(%rsp)
108 vmovups %ymm12, 96(%rsp)
109 vmovups %ymm13, 64(%rsp)
110 vmovups %ymm14, 32(%rsp)
111 vmovups %ymm15, (%rsp)
112 movq %rsi, 264(%rsp)
113 movq %rdi, 256(%rsp)
114 movq %r12, 296(%rsp)
115 cfi_offset_rel_rsp (12, 296)
116 movb %dl, %r12b
117 movq %r13, 288(%rsp)
118 cfi_offset_rel_rsp (13, 288)
119 movl %ecx, %r13d
120 movq %r14, 280(%rsp)
121 cfi_offset_rel_rsp (14, 280)
122 movl %eax, %r14d
123 movq %r15, 272(%rsp)
124 cfi_offset_rel_rsp (15, 272)
125 cfi_remember_state
126
127.LBL_1_6:
128 btl %r14d, %r13d
129 jc .LBL_1_12
130
131.LBL_1_7:
132 lea 1(%r14), %esi
133 btl %esi, %r13d
134 jc .LBL_1_10
135
136.LBL_1_8:
137 incb %r12b
138 addl $2, %r14d
139 cmpb $16, %r12b
140 jb .LBL_1_6
141
142 vmovups 224(%rsp), %ymm8
143 vmovups 192(%rsp), %ymm9
144 vmovups 160(%rsp), %ymm10
145 vmovups 128(%rsp), %ymm11
146 vmovups 96(%rsp), %ymm12
147 vmovups 64(%rsp), %ymm13
148 vmovups 32(%rsp), %ymm14
149 vmovups (%rsp), %ymm15
150 vmovups 384(%rsp), %ymm0
151 movq 264(%rsp), %rsi
152 movq 256(%rsp), %rdi
153 movq 296(%rsp), %r12
154 cfi_restore (%r12)
155 movq 288(%rsp), %r13
156 cfi_restore (%r13)
157 movq 280(%rsp), %r14
158 cfi_restore (%r14)
159 movq 272(%rsp), %r15
160 cfi_restore (%r15)
161 jmp .LBL_1_2
162
163.LBL_1_10:
164 cfi_restore_state
165 movzbl %r12b, %r15d
166 vmovss 324(%rsp,%r15,8), %xmm0
167 vzeroupper
168
169 call JUMPTARGET(logf)
170
171 vmovss %xmm0, 388(%rsp,%r15,8)
172 jmp .LBL_1_8
173
174.LBL_1_12:
175 movzbl %r12b, %r15d
176 vmovss 320(%rsp,%r15,8), %xmm0
177 vzeroupper
178
179 call JUMPTARGET(logf)
180
181 vmovss %xmm0, 384(%rsp,%r15,8)
182 jmp .LBL_1_7
183
184END(_ZGVdN8v_logf_avx2)
185

source code of glibc/sysdeps/x86_64/fpu/multiarch/svml_s_logf8_core_avx2.S