1/* Function log vectorized with AVX-512. KNL and SKX versions.
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_d_log_data.h"
21#include "svml_d_wrapper_impl.h"
22
23 .section .text.evex512, "ax", @progbits
24ENTRY (_ZGVeN8v_log_knl)
25/*
26 ALGORITHM DESCRIPTION:
27
28 log(x) = -log(Rcp) + log(Rcp*x),
29 where Rcp ~ 1/x (accuracy ~9 bits, obtained by
30 rounding HW approximation to 1+9 mantissa bits)
31
32 Reduced argument R=Rcp*x-1 is used to approximate log(1+R) as polynomial
33
34 log(Rcp) = exponent_Rcp*log(2) + log(mantissa_Rcp)
35 -log(mantissa_Rcp) is obtained from a lookup table,
36 accessed by a 9-bit index
37 */
38 pushq %rbp
39 cfi_adjust_cfa_offset (8)
40 cfi_rel_offset (%rbp, 0)
41 movq %rsp, %rbp
42 cfi_def_cfa_register (%rbp)
43 andq $-64, %rsp
44 subq $1280, %rsp
45 movq __svml_dlog_data@GOTPCREL(%rip), %rdx
46 movq $-1, %rax
47
48/* isolate exponent bits */
49 vpsrlq $20, %zmm0, %zmm2
50 vpsrlq $32, %zmm2, %zmm3
51 vpxord %zmm2, %zmm2, %zmm2
52 kxnorw %k3, %k3, %k3
53 vmovups _Two10(%rdx), %zmm1
54 vmovups _One(%rdx), %zmm9
55 vpmovqd %zmm3, %ymm4
56
57/* convert biased exponent to DP format */
58 vcvtdq2pd %ymm4, %zmm13
59
60/* preserve mantissa, set input exponent to 2^(-10) */
61 vpternlogq $248, _ExpMask(%rdx), %zmm0, %zmm1
62 vcmppd $17, _MinNorm(%rdx), %zmm0, %k1
63
64/* reciprocal approximation good to at least 11 bits */
65 vrcp28pd %zmm1, %zmm5
66 vpbroadcastq %rax, %zmm6{%k1}{z}
67 vmovups _poly_coeff_3(%rdx), %zmm15
68 vcmppd $22, _MaxNorm(%rdx), %zmm0, %k2
69 vmovups _Bias1(%rdx), %zmm14
70
71/* round reciprocal to nearest integer, will have 1+9 mantissa bits */
72 vrndscalepd $8, %zmm5, %zmm11
73 vpbroadcastq %rax, %zmm7{%k2}{z}
74
75/* argument reduction started: R = Mantissa*Rcp - 1 */
76 vfmsub213pd %zmm9, %zmm11, %zmm1
77
78/* calculate index for table lookup */
79 vpsrlq $40, %zmm11, %zmm10
80 vgatherqpd _LogRcp_lookup(%rdx,%zmm10), %zmm2{%k3}
81 vcmppd $30, _Threshold(%rdx), %zmm11, %k1
82
83/* combine and get argument value range mask */
84 vporq %zmm7, %zmm6, %zmm8
85
86/* exponent*log(2.0) */
87 vmovups _poly_coeff_1(%rdx), %zmm11
88 vmulpd %zmm1, %zmm1, %zmm10
89 vptestmq %zmm8, %zmm8, %k0
90 vfmadd213pd _poly_coeff_4(%rdx), %zmm1, %zmm15
91 kmovw %k0, %ecx
92
93/* polynomial computation */
94 vfmadd213pd _poly_coeff_2(%rdx), %zmm1, %zmm11
95 movzbl %cl, %ecx
96 vpbroadcastq %rax, %zmm12{%k1}{z}
97 vfmadd213pd %zmm15, %zmm10, %zmm11
98 vpternlogq $248, _Bias(%rdx), %zmm12, %zmm14
99
100/*
101 Table stores -log(0.5*mantissa) for larger mantissas,
102 adjust exponent accordingly
103 */
104 vsubpd %zmm14, %zmm13, %zmm3
105
106/*
107 reconstruction:
108 (exponent*log(2)) + (LogRcp + (R+poly))
109 */
110 vfmadd213pd %zmm1, %zmm10, %zmm11
111 vaddpd %zmm2, %zmm11, %zmm1
112 vfmadd132pd _L2(%rdx), %zmm1, %zmm3
113 testl %ecx, %ecx
114 jne .LBL_1_3
115
116.LBL_1_2:
117 cfi_remember_state
118 vmovaps %zmm3, %zmm0
119 movq %rbp, %rsp
120 cfi_def_cfa_register (%rsp)
121 popq %rbp
122 cfi_adjust_cfa_offset (-8)
123 cfi_restore (%rbp)
124 ret
125
126.LBL_1_3:
127 cfi_restore_state
128 vmovups %zmm0, 1152(%rsp)
129 vmovups %zmm3, 1216(%rsp)
130 je .LBL_1_2
131
132 xorb %dl, %dl
133 kmovw %k4, 1048(%rsp)
134 xorl %eax, %eax
135 kmovw %k5, 1040(%rsp)
136 kmovw %k6, 1032(%rsp)
137 kmovw %k7, 1024(%rsp)
138 vmovups %zmm16, 960(%rsp)
139 vmovups %zmm17, 896(%rsp)
140 vmovups %zmm18, 832(%rsp)
141 vmovups %zmm19, 768(%rsp)
142 vmovups %zmm20, 704(%rsp)
143 vmovups %zmm21, 640(%rsp)
144 vmovups %zmm22, 576(%rsp)
145 vmovups %zmm23, 512(%rsp)
146 vmovups %zmm24, 448(%rsp)
147 vmovups %zmm25, 384(%rsp)
148 vmovups %zmm26, 320(%rsp)
149 vmovups %zmm27, 256(%rsp)
150 vmovups %zmm28, 192(%rsp)
151 vmovups %zmm29, 128(%rsp)
152 vmovups %zmm30, 64(%rsp)
153 vmovups %zmm31, (%rsp)
154 movq %rsi, 1064(%rsp)
155 movq %rdi, 1056(%rsp)
156 movq %r12, 1096(%rsp)
157 cfi_offset_rel_rsp (12, 1096)
158 movb %dl, %r12b
159 movq %r13, 1088(%rsp)
160 cfi_offset_rel_rsp (13, 1088)
161 movl %ecx, %r13d
162 movq %r14, 1080(%rsp)
163 cfi_offset_rel_rsp (14, 1080)
164 movl %eax, %r14d
165 movq %r15, 1072(%rsp)
166 cfi_offset_rel_rsp (15, 1072)
167 cfi_remember_state
168
169.LBL_1_6:
170 btl %r14d, %r13d
171 jc .LBL_1_12
172
173.LBL_1_7:
174 lea 1(%r14), %esi
175 btl %esi, %r13d
176 jc .LBL_1_10
177
178.LBL_1_8:
179 addb $1, %r12b
180 addl $2, %r14d
181 cmpb $16, %r12b
182 jb .LBL_1_6
183
184 kmovw 1048(%rsp), %k4
185 movq 1064(%rsp), %rsi
186 kmovw 1040(%rsp), %k5
187 movq 1056(%rsp), %rdi
188 kmovw 1032(%rsp), %k6
189 movq 1096(%rsp), %r12
190 cfi_restore (%r12)
191 movq 1088(%rsp), %r13
192 cfi_restore (%r13)
193 kmovw 1024(%rsp), %k7
194 vmovups 960(%rsp), %zmm16
195 vmovups 896(%rsp), %zmm17
196 vmovups 832(%rsp), %zmm18
197 vmovups 768(%rsp), %zmm19
198 vmovups 704(%rsp), %zmm20
199 vmovups 640(%rsp), %zmm21
200 vmovups 576(%rsp), %zmm22
201 vmovups 512(%rsp), %zmm23
202 vmovups 448(%rsp), %zmm24
203 vmovups 384(%rsp), %zmm25
204 vmovups 320(%rsp), %zmm26
205 vmovups 256(%rsp), %zmm27
206 vmovups 192(%rsp), %zmm28
207 vmovups 128(%rsp), %zmm29
208 vmovups 64(%rsp), %zmm30
209 vmovups (%rsp), %zmm31
210 movq 1080(%rsp), %r14
211 cfi_restore (%r14)
212 movq 1072(%rsp), %r15
213 cfi_restore (%r15)
214 vmovups 1216(%rsp), %zmm3
215 jmp .LBL_1_2
216
217.LBL_1_10:
218 cfi_restore_state
219 movzbl %r12b, %r15d
220 shlq $4, %r15
221 vmovsd 1160(%rsp,%r15), %xmm0
222 call JUMPTARGET(log)
223 vmovsd %xmm0, 1224(%rsp,%r15)
224 jmp .LBL_1_8
225
226.LBL_1_12:
227 movzbl %r12b, %r15d
228 shlq $4, %r15
229 vmovsd 1152(%rsp,%r15), %xmm0
230 call JUMPTARGET(log)
231 vmovsd %xmm0, 1216(%rsp,%r15)
232 jmp .LBL_1_7
233END (_ZGVeN8v_log_knl)
234
235ENTRY (_ZGVeN8v_log_skx)
236/*
237 ALGORITHM DESCRIPTION:
238
239 log(x) = -log(Rcp) + log(Rcp*x),
240 where Rcp ~ 1/x (accuracy ~9 bits,
241 obtained by rounding HW approximation to 1+9 mantissa bits)
242
243 Reduced argument R=Rcp*x-1 is used to approximate log(1+R) as polynomial
244
245 log(Rcp) = exponent_Rcp*log(2) + log(mantissa_Rcp)
246 -log(mantissa_Rcp) is obtained from a lookup table,
247 accessed by a 9-bit index
248 */
249 pushq %rbp
250 cfi_adjust_cfa_offset (8)
251 cfi_rel_offset (%rbp, 0)
252 movq %rsp, %rbp
253 cfi_def_cfa_register (%rbp)
254 andq $-64, %rsp
255 subq $1280, %rsp
256 movq __svml_dlog_data@GOTPCREL(%rip), %rax
257 vmovaps %zmm0, %zmm3
258 kxnorw %k3, %k3, %k3
259 vmovups _Two10(%rax), %zmm2
260 vmovups _Threshold(%rax), %zmm14
261 vmovups _One(%rax), %zmm11
262 vcmppd $21, _MinNorm(%rax), %zmm3, %k1
263 vcmppd $18, _MaxNorm(%rax), %zmm3, %k2
264
265/* isolate exponent bits */
266 vpsrlq $20, %zmm3, %zmm4
267
268/* preserve mantissa, set input exponent to 2^(-10) */
269 vpternlogq $248, _ExpMask(%rax), %zmm3, %zmm2
270 vpternlogd $0xff, %zmm1, %zmm1, %zmm1
271 vpsrlq $32, %zmm4, %zmm6
272
273/* reciprocal approximation good to at least 11 bits */
274 vrcp14pd %zmm2, %zmm5
275
276/* exponent*log(2.0) */
277 vmovups _poly_coeff_1(%rax), %zmm4
278 vpmovqd %zmm6, %ymm7
279
280/* round reciprocal to nearest integer, will have 1+9 mantissa bits */
281 vrndscalepd $8, %zmm5, %zmm0
282
283/* calculate index for table lookup */
284 vpsrlq $40, %zmm0, %zmm12
285
286/* argument reduction started: R = Mantissa*Rcp - 1 */
287 vfmsub213pd %zmm11, %zmm0, %zmm2
288 vpmovqd %zmm12, %ymm13
289
290/* polynomial computation */
291 vfmadd213pd _poly_coeff_2(%rax), %zmm2, %zmm4
292 vmovaps %zmm1, %zmm8
293 vmovaps %zmm1, %zmm9
294 vpxord %zmm5, %zmm5, %zmm5
295 vgatherdpd _LogRcp_lookup(%rax,%ymm13), %zmm5{%k3}
296 vmovups _Bias1(%rax), %zmm13
297 vpandnq %zmm3, %zmm3, %zmm8{%k1}
298 vcmppd $21, %zmm0, %zmm14, %k1
299 vpandnq %zmm14, %zmm14, %zmm1{%k1}
300 vmulpd %zmm2, %zmm2, %zmm14
301 vpternlogq $248, _Bias(%rax), %zmm1, %zmm13
302 vmovups _poly_coeff_3(%rax), %zmm1
303 vfmadd213pd _poly_coeff_4(%rax), %zmm2, %zmm1
304 vfmadd213pd %zmm1, %zmm14, %zmm4
305
306/*
307 reconstruction:
308 (exponent*log(2)) + (LogRcp + (R+poly))
309 */
310 vfmadd213pd %zmm2, %zmm14, %zmm4
311 vaddpd %zmm5, %zmm4, %zmm2
312 vpandnq %zmm3, %zmm3, %zmm9{%k2}
313
314/* combine and get argument value range mask */
315 vorpd %zmm9, %zmm8, %zmm10
316 vcmppd $3, %zmm10, %zmm10, %k0
317 kmovw %k0, %ecx
318
319/* convert biased exponent to DP format */
320 vcvtdq2pd %ymm7, %zmm15
321
322/*
323 Table stores -log(0.5*mantissa) for larger mantissas,
324 adjust exponent accordingly
325 */
326 vsubpd %zmm13, %zmm15, %zmm0
327 vfmadd132pd _L2(%rax), %zmm2, %zmm0
328 testl %ecx, %ecx
329 jne .LBL_2_3
330
331.LBL_2_2:
332 cfi_remember_state
333 movq %rbp, %rsp
334 cfi_def_cfa_register (%rsp)
335 popq %rbp
336 cfi_adjust_cfa_offset (-8)
337 cfi_restore (%rbp)
338 ret
339
340.LBL_2_3:
341 cfi_restore_state
342 vmovups %zmm3, 1152(%rsp)
343 vmovups %zmm0, 1216(%rsp)
344 je .LBL_2_2
345
346 xorb %dl, %dl
347 xorl %eax, %eax
348 kmovw %k4, 1048(%rsp)
349 kmovw %k5, 1040(%rsp)
350 kmovw %k6, 1032(%rsp)
351 kmovw %k7, 1024(%rsp)
352 vmovups %zmm16, 960(%rsp)
353 vmovups %zmm17, 896(%rsp)
354 vmovups %zmm18, 832(%rsp)
355 vmovups %zmm19, 768(%rsp)
356 vmovups %zmm20, 704(%rsp)
357 vmovups %zmm21, 640(%rsp)
358 vmovups %zmm22, 576(%rsp)
359 vmovups %zmm23, 512(%rsp)
360 vmovups %zmm24, 448(%rsp)
361 vmovups %zmm25, 384(%rsp)
362 vmovups %zmm26, 320(%rsp)
363 vmovups %zmm27, 256(%rsp)
364 vmovups %zmm28, 192(%rsp)
365 vmovups %zmm29, 128(%rsp)
366 vmovups %zmm30, 64(%rsp)
367 vmovups %zmm31, (%rsp)
368 movq %rsi, 1064(%rsp)
369 movq %rdi, 1056(%rsp)
370 movq %r12, 1096(%rsp)
371 cfi_offset_rel_rsp (12, 1096)
372 movb %dl, %r12b
373 movq %r13, 1088(%rsp)
374 cfi_offset_rel_rsp (13, 1088)
375 movl %ecx, %r13d
376 movq %r14, 1080(%rsp)
377 cfi_offset_rel_rsp (14, 1080)
378 movl %eax, %r14d
379 movq %r15, 1072(%rsp)
380 cfi_offset_rel_rsp (15, 1072)
381 cfi_remember_state
382
383.LBL_2_6:
384 btl %r14d, %r13d
385 jc .LBL_2_12
386
387.LBL_2_7:
388 lea 1(%r14), %esi
389 btl %esi, %r13d
390 jc .LBL_2_10
391
392.LBL_2_8:
393 incb %r12b
394 addl $2, %r14d
395 cmpb $16, %r12b
396 jb .LBL_2_6
397
398 kmovw 1048(%rsp), %k4
399 kmovw 1040(%rsp), %k5
400 kmovw 1032(%rsp), %k6
401 kmovw 1024(%rsp), %k7
402 vmovups 960(%rsp), %zmm16
403 vmovups 896(%rsp), %zmm17
404 vmovups 832(%rsp), %zmm18
405 vmovups 768(%rsp), %zmm19
406 vmovups 704(%rsp), %zmm20
407 vmovups 640(%rsp), %zmm21
408 vmovups 576(%rsp), %zmm22
409 vmovups 512(%rsp), %zmm23
410 vmovups 448(%rsp), %zmm24
411 vmovups 384(%rsp), %zmm25
412 vmovups 320(%rsp), %zmm26
413 vmovups 256(%rsp), %zmm27
414 vmovups 192(%rsp), %zmm28
415 vmovups 128(%rsp), %zmm29
416 vmovups 64(%rsp), %zmm30
417 vmovups (%rsp), %zmm31
418 vmovups 1216(%rsp), %zmm0
419 movq 1064(%rsp), %rsi
420 movq 1056(%rsp), %rdi
421 movq 1096(%rsp), %r12
422 cfi_restore (%r12)
423 movq 1088(%rsp), %r13
424 cfi_restore (%r13)
425 movq 1080(%rsp), %r14
426 cfi_restore (%r14)
427 movq 1072(%rsp), %r15
428 cfi_restore (%r15)
429 jmp .LBL_2_2
430
431.LBL_2_10:
432 cfi_restore_state
433 movzbl %r12b, %r15d
434 shlq $4, %r15
435 vmovsd 1160(%rsp,%r15), %xmm0
436 vzeroupper
437 vmovsd 1160(%rsp,%r15), %xmm0
438
439 call JUMPTARGET(log)
440
441 vmovsd %xmm0, 1224(%rsp,%r15)
442 jmp .LBL_2_8
443
444.LBL_2_12:
445 movzbl %r12b, %r15d
446 shlq $4, %r15
447 vmovsd 1152(%rsp,%r15), %xmm0
448 vzeroupper
449 vmovsd 1152(%rsp,%r15), %xmm0
450
451 call JUMPTARGET(log)
452
453 vmovsd %xmm0, 1216(%rsp,%r15)
454 jmp .LBL_2_7
455END (_ZGVeN8v_log_skx)
456

source code of glibc/sysdeps/x86_64/fpu/multiarch/svml_d_log8_core_avx512.S