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/* Function log vectorized with AVX2.
Copyright (C) 2014-2016 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <sysdep.h>
#include "svml_d_log_data.h"
.text
ENTRY (_ZGVdN4v_log_avx2)
/* ALGORITHM DESCRIPTION:
log(x) = -log(Rcp) + log(Rcp*x),
where Rcp ~ 1/x (accuracy ~9 bits, obtained by rounding
HW approximation to 1+9 mantissa bits)
Reduced argument R=Rcp*x-1 is used to approximate log(1+R) as polynomial
log(Rcp) = exponent_Rcp*log(2) + log(mantissa_Rcp)
-log(mantissa_Rcp) is obtained from a lookup table,
accessed by a 9-bit index
*/
pushq %rbp
cfi_adjust_cfa_offset (8)
cfi_rel_offset (%rbp, 0)
movq %rsp, %rbp
cfi_def_cfa_register (%rbp)
andq $-64, %rsp
subq $448, %rsp
movq __svml_dlog_data@GOTPCREL(%rip), %rax
vmovdqa %ymm0, %ymm5
/* isolate exponent bits */
vpsrlq $20, %ymm5, %ymm0
/* preserve mantissa, set input exponent to 2^(-10) */
vandpd _ExpMask(%rax), %ymm5, %ymm6
vorpd _Two10(%rax), %ymm6, %ymm4
/* reciprocal approximation good to at least 11 bits */
vcvtpd2ps %ymm4, %xmm7
vrcpps %xmm7, %xmm1
vcmplt_oqpd _MinNorm(%rax), %ymm5, %ymm7
vcvtps2pd %xmm1, %ymm3
vcmpnle_uqpd _MaxNorm(%rax), %ymm5, %ymm1
vextracti128 $1, %ymm0, %xmm2
vshufps $221, %xmm2, %xmm0, %xmm6
/* round reciprocal to nearest integer, will have 1+9 mantissa bits */
vroundpd $0, %ymm3, %ymm2
/* convert biased exponent to DP format */
vcvtdq2pd %xmm6, %ymm0
/* combine and get argument value range mask */
vorpd %ymm1, %ymm7, %ymm3
vmovupd _One(%rax), %ymm1
vmovmskpd %ymm3, %ecx
/* calculate index for table lookup */
vpsrlq $40, %ymm2, %ymm3
/* argument reduction started: R = Mantissa*Rcp - 1 */
vfmsub213pd %ymm1, %ymm2, %ymm4
vcmpgt_oqpd _Threshold(%rax), %ymm2, %ymm2
vpcmpeqd %ymm6, %ymm6, %ymm6
vxorpd %ymm1, %ymm1, %ymm1
vgatherqpd %ymm6, _LogRcp_lookup(%rax,%ymm3), %ymm1
/* exponent*log(2.0) */
vmovupd _poly_coeff_1(%rax), %ymm6
vmulpd %ymm4, %ymm4, %ymm3
/* polynomial computation */
vfmadd213pd _poly_coeff_2(%rax), %ymm4, %ymm6
vandpd _Bias(%rax), %ymm2, %ymm7
vorpd _Bias1(%rax), %ymm7, %ymm2
/*
Table stores -log(0.5*mantissa) for larger mantissas,
adjust exponent accordingly
*/
vsubpd %ymm2, %ymm0, %ymm0
vmovupd _poly_coeff_3(%rax), %ymm2
vfmadd213pd _poly_coeff_4(%rax), %ymm4, %ymm2
vfmadd213pd %ymm2, %ymm3, %ymm6
/*
reconstruction:
(exponent*log(2)) + (LogRcp + (R+poly))
*/
vfmadd213pd %ymm4, %ymm3, %ymm6
vaddpd %ymm1, %ymm6, %ymm4
vfmadd132pd _L2(%rax), %ymm4, %ymm0
testl %ecx, %ecx
jne .LBL_1_3
.LBL_1_2:
cfi_remember_state
movq %rbp, %rsp
cfi_def_cfa_register (%rsp)
popq %rbp
cfi_adjust_cfa_offset (-8)
cfi_restore (%rbp)
ret
.LBL_1_3:
cfi_restore_state
vmovupd %ymm5, 320(%rsp)
vmovupd %ymm0, 384(%rsp)
je .LBL_1_2
xorb %dl, %dl
xorl %eax, %eax
vmovups %ymm8, 224(%rsp)
vmovups %ymm9, 192(%rsp)
vmovups %ymm10, 160(%rsp)
vmovups %ymm11, 128(%rsp)
vmovups %ymm12, 96(%rsp)
vmovups %ymm13, 64(%rsp)
vmovups %ymm14, 32(%rsp)
vmovups %ymm15, (%rsp)
movq %rsi, 264(%rsp)
movq %rdi, 256(%rsp)
movq %r12, 296(%rsp)
cfi_offset_rel_rsp (12, 296)
movb %dl, %r12b
movq %r13, 288(%rsp)
cfi_offset_rel_rsp (13, 288)
movl %ecx, %r13d
movq %r14, 280(%rsp)
cfi_offset_rel_rsp (14, 280)
movl %eax, %r14d
movq %r15, 272(%rsp)
cfi_offset_rel_rsp (15, 272)
cfi_remember_state
.LBL_1_6:
btl %r14d, %r13d
jc .LBL_1_12
.LBL_1_7:
lea 1(%r14), %esi
btl %esi, %r13d
jc .LBL_1_10
.LBL_1_8:
incb %r12b
addl $2, %r14d
cmpb $16, %r12b
jb .LBL_1_6
vmovups 224(%rsp), %ymm8
vmovups 192(%rsp), %ymm9
vmovups 160(%rsp), %ymm10
vmovups 128(%rsp), %ymm11
vmovups 96(%rsp), %ymm12
vmovups 64(%rsp), %ymm13
vmovups 32(%rsp), %ymm14
vmovups (%rsp), %ymm15
vmovupd 384(%rsp), %ymm0
movq 264(%rsp), %rsi
movq 256(%rsp), %rdi
movq 296(%rsp), %r12
cfi_restore (%r12)
movq 288(%rsp), %r13
cfi_restore (%r13)
movq 280(%rsp), %r14
cfi_restore (%r14)
movq 272(%rsp), %r15
cfi_restore (%r15)
jmp .LBL_1_2
.LBL_1_10:
cfi_restore_state
movzbl %r12b, %r15d
shlq $4, %r15
vmovsd 328(%rsp,%r15), %xmm0
vzeroupper
call log@PLT
vmovsd %xmm0, 392(%rsp,%r15)
jmp .LBL_1_8
.LBL_1_12:
movzbl %r12b, %r15d
shlq $4, %r15
vmovsd 320(%rsp,%r15), %xmm0
vzeroupper
call log@PLT
vmovsd %xmm0, 384(%rsp,%r15)
jmp .LBL_1_7
END (_ZGVdN4v_log_avx2)
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