1/* Function log2f vectorized with AVX2.
2 Copyright (C) 2021-2024 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/*
20 * ALGORITHM DESCRIPTION:
21 *
22 * Get short reciprocal approximation Rcp ~ 1/mantissa(x)
23 * R = Rcp*x - 1.0
24 * log2(x) = k - log2(Rcp) + poly_approximation(R)
25 * log2(Rcp) is tabulated
26 *
27 *
28 */
29
30/* Offsets for data table __svml_slog2_data_internal
31 */
32#define MinNorm 0
33#define MaxNorm 32
34#define iBrkValue 64
35#define iOffExpoMask 96
36#define One 128
37#define sPoly 160
38
39#include <sysdep.h>
40
41 .section .text.avx2, "ax", @progbits
42ENTRY(_ZGVdN8v_log2f_avx2)
43 pushq %rbp
44 cfi_def_cfa_offset(16)
45 movq %rsp, %rbp
46 cfi_def_cfa(6, 16)
47 cfi_offset(6, -16)
48 andq $-32, %rsp
49 subq $96, %rsp
50
51 /* reduction: compute r, n */
52 vmovups iBrkValue+__svml_slog2_data_internal(%rip), %ymm4
53 vmovups sPoly+64+__svml_slog2_data_internal(%rip), %ymm9
54 vmovups sPoly+128+__svml_slog2_data_internal(%rip), %ymm10
55 vmovups sPoly+192+__svml_slog2_data_internal(%rip), %ymm12
56 vpsubd %ymm4, %ymm0, %ymm1
57 vcmplt_oqps MinNorm+__svml_slog2_data_internal(%rip), %ymm0, %ymm5
58 vcmpnle_uqps MaxNorm+__svml_slog2_data_internal(%rip), %ymm0, %ymm6
59 vpand iOffExpoMask+__svml_slog2_data_internal(%rip), %ymm1, %ymm3
60 vpsrad $23, %ymm1, %ymm2
61 vmovups sPoly+__svml_slog2_data_internal(%rip), %ymm1
62 vpaddd %ymm4, %ymm3, %ymm8
63 vcvtdq2ps %ymm2, %ymm14
64 vsubps One+__svml_slog2_data_internal(%rip), %ymm8, %ymm13
65 vfmadd213ps sPoly+32+__svml_slog2_data_internal(%rip), %ymm13, %ymm1
66 vfmadd213ps sPoly+96+__svml_slog2_data_internal(%rip), %ymm13, %ymm9
67 vmulps %ymm13, %ymm13, %ymm11
68 vfmadd213ps sPoly+160+__svml_slog2_data_internal(%rip), %ymm13, %ymm10
69 vfmadd213ps sPoly+224+__svml_slog2_data_internal(%rip), %ymm13, %ymm12
70 vfmadd213ps %ymm9, %ymm11, %ymm1
71 vfmadd213ps %ymm10, %ymm11, %ymm1
72 vfmadd213ps %ymm12, %ymm11, %ymm1
73 vfmadd213ps sPoly+256+__svml_slog2_data_internal(%rip), %ymm13, %ymm1
74 vorps %ymm6, %ymm5, %ymm7
75
76 /* combine and get argument value range mask */
77 vmovmskps %ymm7, %edx
78 vfmadd213ps %ymm14, %ymm13, %ymm1
79 testl %edx, %edx
80
81 /* Go to special inputs processing branch */
82 jne L(SPECIAL_VALUES_BRANCH)
83 # LOE rbx r12 r13 r14 r15 edx ymm0 ymm1
84
85 /* Restore registers
86 * and exit the function
87 */
88
89L(EXIT):
90 vmovaps %ymm1, %ymm0
91 movq %rbp, %rsp
92 popq %rbp
93 cfi_def_cfa(7, 8)
94 cfi_restore(6)
95 ret
96 cfi_def_cfa(6, 16)
97 cfi_offset(6, -16)
98
99 /* Branch to process
100 * special inputs
101 */
102
103L(SPECIAL_VALUES_BRANCH):
104 vmovups %ymm0, 32(%rsp)
105 vmovups %ymm1, 64(%rsp)
106 # LOE rbx r12 r13 r14 r15 edx ymm1
107
108 xorl %eax, %eax
109 # LOE rbx r12 r13 r14 r15 eax edx
110
111 vzeroupper
112 movq %r12, 16(%rsp)
113 /* DW_CFA_expression: r12 (r12) (DW_OP_lit8; DW_OP_minus; DW_OP_const4s: -32; DW_OP_and; DW_OP_const4s: -80; DW_OP_plus) */
114 .cfi_escape 0x10, 0x0c, 0x0e, 0x38, 0x1c, 0x0d, 0xe0, 0xff, 0xff, 0xff, 0x1a, 0x0d, 0xb0, 0xff, 0xff, 0xff, 0x22
115 movl %eax, %r12d
116 movq %r13, 8(%rsp)
117 /* DW_CFA_expression: r13 (r13) (DW_OP_lit8; DW_OP_minus; DW_OP_const4s: -32; DW_OP_and; DW_OP_const4s: -88; DW_OP_plus) */
118 .cfi_escape 0x10, 0x0d, 0x0e, 0x38, 0x1c, 0x0d, 0xe0, 0xff, 0xff, 0xff, 0x1a, 0x0d, 0xa8, 0xff, 0xff, 0xff, 0x22
119 movl %edx, %r13d
120 movq %r14, (%rsp)
121 /* DW_CFA_expression: r14 (r14) (DW_OP_lit8; DW_OP_minus; DW_OP_const4s: -32; DW_OP_and; DW_OP_const4s: -96; DW_OP_plus) */
122 .cfi_escape 0x10, 0x0e, 0x0e, 0x38, 0x1c, 0x0d, 0xe0, 0xff, 0xff, 0xff, 0x1a, 0x0d, 0xa0, 0xff, 0xff, 0xff, 0x22
123 # LOE rbx r15 r12d r13d
124
125 /* Range mask
126 * bits check
127 */
128
129L(RANGEMASK_CHECK):
130 btl %r12d, %r13d
131
132 /* Call scalar math function */
133 jc L(SCALAR_MATH_CALL)
134 # LOE rbx r15 r12d r13d
135
136 /* Special inputs
137 * processing loop
138 */
139
140L(SPECIAL_VALUES_LOOP):
141 incl %r12d
142 cmpl $8, %r12d
143
144 /* Check bits in range mask */
145 jl L(RANGEMASK_CHECK)
146 # LOE rbx r15 r12d r13d
147
148 movq 16(%rsp), %r12
149 cfi_restore(12)
150 movq 8(%rsp), %r13
151 cfi_restore(13)
152 movq (%rsp), %r14
153 cfi_restore(14)
154 vmovups 64(%rsp), %ymm1
155
156 /* Go to exit */
157 jmp L(EXIT)
158 /* DW_CFA_expression: r12 (r12) (DW_OP_lit8; DW_OP_minus; DW_OP_const4s: -32; DW_OP_and; DW_OP_const4s: -80; DW_OP_plus) */
159 .cfi_escape 0x10, 0x0c, 0x0e, 0x38, 0x1c, 0x0d, 0xe0, 0xff, 0xff, 0xff, 0x1a, 0x0d, 0xb0, 0xff, 0xff, 0xff, 0x22
160 /* DW_CFA_expression: r13 (r13) (DW_OP_lit8; DW_OP_minus; DW_OP_const4s: -32; DW_OP_and; DW_OP_const4s: -88; DW_OP_plus) */
161 .cfi_escape 0x10, 0x0d, 0x0e, 0x38, 0x1c, 0x0d, 0xe0, 0xff, 0xff, 0xff, 0x1a, 0x0d, 0xa8, 0xff, 0xff, 0xff, 0x22
162 /* DW_CFA_expression: r14 (r14) (DW_OP_lit8; DW_OP_minus; DW_OP_const4s: -32; DW_OP_and; DW_OP_const4s: -96; DW_OP_plus) */
163 .cfi_escape 0x10, 0x0e, 0x0e, 0x38, 0x1c, 0x0d, 0xe0, 0xff, 0xff, 0xff, 0x1a, 0x0d, 0xa0, 0xff, 0xff, 0xff, 0x22
164 # LOE rbx r12 r13 r14 r15 ymm1
165
166 /* Scalar math function call
167 * to process special input
168 */
169
170L(SCALAR_MATH_CALL):
171 movl %r12d, %r14d
172 vmovss 32(%rsp, %r14, 4), %xmm0
173 call log2f@PLT
174 # LOE rbx r14 r15 r12d r13d xmm0
175
176 vmovss %xmm0, 64(%rsp, %r14, 4)
177
178 /* Process special inputs in loop */
179 jmp L(SPECIAL_VALUES_LOOP)
180 # LOE rbx r15 r12d r13d
181END(_ZGVdN8v_log2f_avx2)
182
183 .section .rodata, "a"
184 .align 32
185
186#ifdef __svml_slog2_data_internal_typedef
187typedef unsigned int VUINT32;
188typedef struct {
189 __declspec(align(32)) VUINT32 MinNorm[8][1];
190 __declspec(align(32)) VUINT32 MaxNorm[8][1];
191 __declspec(align(32)) VUINT32 iBrkValue[8][1];
192 __declspec(align(32)) VUINT32 iOffExpoMask[8][1];
193 __declspec(align(32)) VUINT32 One[8][1];
194 __declspec(align(32)) VUINT32 sPoly[9][8][1];
195} __svml_slog2_data_internal;
196#endif
197__svml_slog2_data_internal:
198 /* MinNorm */
199 .long 0x00800000, 0x00800000, 0x00800000, 0x00800000, 0x00800000, 0x00800000, 0x00800000, 0x00800000
200 /* MaxNorm */
201 .align 32
202 .long 0x7f7fffff, 0x7f7fffff, 0x7f7fffff, 0x7f7fffff, 0x7f7fffff, 0x7f7fffff, 0x7f7fffff, 0x7f7fffff
203 /* iBrkValue = SP 2/3 */
204 .align 32
205 .long 0x3f2aaaab, 0x3f2aaaab, 0x3f2aaaab, 0x3f2aaaab, 0x3f2aaaab, 0x3f2aaaab, 0x3f2aaaab, 0x3f2aaaab
206 /* iOffExpoMask = SP significand mask */
207 .align 32
208 .long 0x007fffff, 0x007fffff, 0x007fffff, 0x007fffff, 0x007fffff, 0x007fffff, 0x007fffff, 0x007fffff
209 /* sOne = SP 1.0 */
210 .align 32
211 .long 0x3f800000, 0x3f800000, 0x3f800000, 0x3f800000, 0x3f800000, 0x3f800000, 0x3f800000, 0x3f800000
212 /* spoly[9] */
213 .align 32
214 .long 0x3e554012, 0x3e554012, 0x3e554012, 0x3e554012, 0x3e554012, 0x3e554012, 0x3e554012, 0x3e554012 /* coeff9 */
215 .long 0xbe638E14, 0xbe638E14, 0xbe638E14, 0xbe638E14, 0xbe638E14, 0xbe638E14, 0xbe638E14, 0xbe638E14 /* coeff8 */
216 .long 0x3e4D660B, 0x3e4D660B, 0x3e4D660B, 0x3e4D660B, 0x3e4D660B, 0x3e4D660B, 0x3e4D660B, 0x3e4D660B /* coeff7 */
217 .long 0xbe727824, 0xbe727824, 0xbe727824, 0xbe727824, 0xbe727824, 0xbe727824, 0xbe727824, 0xbe727824 /* coeff6 */
218 .long 0x3e93DD07, 0x3e93DD07, 0x3e93DD07, 0x3e93DD07, 0x3e93DD07, 0x3e93DD07, 0x3e93DD07, 0x3e93DD07 /* coeff5 */
219 .long 0xbeB8B969, 0xbeB8B969, 0xbeB8B969, 0xbeB8B969, 0xbeB8B969, 0xbeB8B969, 0xbeB8B969, 0xbeB8B969 /* coeff4 */
220 .long 0x3eF637C0, 0x3eF637C0, 0x3eF637C0, 0x3eF637C0, 0x3eF637C0, 0x3eF637C0, 0x3eF637C0, 0x3eF637C0 /* coeff3 */
221 .long 0xbf38AA2B, 0xbf38AA2B, 0xbf38AA2B, 0xbf38AA2B, 0xbf38AA2B, 0xbf38AA2B, 0xbf38AA2B, 0xbf38AA2B /* coeff2 */
222 .long 0x3fB8AA3B, 0x3fB8AA3B, 0x3fB8AA3B, 0x3fB8AA3B, 0x3fB8AA3B, 0x3fB8AA3B, 0x3fB8AA3B, 0x3fB8AA3B /* coeff1 */
223 .align 32
224 .type __svml_slog2_data_internal, @object
225 .size __svml_slog2_data_internal, .-__svml_slog2_data_internal
226

source code of glibc/sysdeps/x86_64/fpu/multiarch/svml_s_log2f8_core_avx2.S