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/* Function log vectorized with SSE4.
Copyright (C) 2014-2018 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 (_ZGVbN2v_log_sse4)
/*
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 $320, %rsp
movaps %xmm0, %xmm6
movq __svml_dlog_data@GOTPCREL(%rip), %r8
movaps %xmm6, %xmm3
movaps %xmm6, %xmm2
/* isolate exponent bits */
movaps %xmm6, %xmm1
psrlq $20, %xmm1
movups _ExpMask(%r8), %xmm5
/* preserve mantissa, set input exponent to 2^(-10) */
andps %xmm6, %xmm5
orps _Two10(%r8), %xmm5
/* reciprocal approximation good to at least 11 bits */
cvtpd2ps %xmm5, %xmm7
cmpltpd _MinNorm(%r8), %xmm3
cmpnlepd _MaxNorm(%r8), %xmm2
movlhps %xmm7, %xmm7
/* combine and get argument value range mask */
orps %xmm2, %xmm3
rcpps %xmm7, %xmm0
movmskpd %xmm3, %eax
movups _HalfMask(%r8), %xmm2
/* argument reduction started: R = Mantissa*Rcp - 1 */
andps %xmm5, %xmm2
cvtps2pd %xmm0, %xmm4
subpd %xmm2, %xmm5
/* round reciprocal to nearest integer, will have 1+9 mantissa bits */
roundpd $0, %xmm4, %xmm4
mulpd %xmm4, %xmm2
mulpd %xmm4, %xmm5
subpd _One(%r8), %xmm2
addpd %xmm2, %xmm5
movups _Threshold(%r8), %xmm2
/* calculate index for table lookup */
movaps %xmm4, %xmm3
cmpltpd %xmm4, %xmm2
pshufd $221, %xmm1, %xmm7
psrlq $40, %xmm3
/* convert biased exponent to DP format */
cvtdq2pd %xmm7, %xmm0
movd %xmm3, %edx
movups _poly_coeff_1(%r8), %xmm4
/* polynomial computation */
mulpd %xmm5, %xmm4
andps _Bias(%r8), %xmm2
orps _Bias1(%r8), %xmm2
/*
Table stores -log(0.5*mantissa) for larger mantissas,
adjust exponent accordingly
*/
subpd %xmm2, %xmm0
addpd _poly_coeff_2(%r8), %xmm4
/* exponent*log(2.0) */
mulpd _L2(%r8), %xmm0
movaps %xmm5, %xmm2
mulpd %xmm5, %xmm2
movups _poly_coeff_3(%r8), %xmm7
mulpd %xmm5, %xmm7
mulpd %xmm2, %xmm4
addpd _poly_coeff_4(%r8), %xmm7
addpd %xmm4, %xmm7
mulpd %xmm7, %xmm2
movslq %edx, %rdx
pextrd $2, %xmm3, %ecx
/*
reconstruction:
(exponent*log(2)) + (LogRcp + (R+poly))
*/
addpd %xmm2, %xmm5
movslq %ecx, %rcx
movsd _LogRcp_lookup(%r8,%rdx), %xmm1
movhpd _LogRcp_lookup(%r8,%rcx), %xmm1
addpd %xmm5, %xmm1
addpd %xmm1, %xmm0
testl %eax, %eax
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
movups %xmm6, 192(%rsp)
movups %xmm0, 256(%rsp)
je .LBL_1_2
xorb %cl, %cl
xorl %edx, %edx
movups %xmm8, 112(%rsp)
movups %xmm9, 96(%rsp)
movups %xmm10, 80(%rsp)
movups %xmm11, 64(%rsp)
movups %xmm12, 48(%rsp)
movups %xmm13, 32(%rsp)
movups %xmm14, 16(%rsp)
movups %xmm15, (%rsp)
movq %rsi, 136(%rsp)
movq %rdi, 128(%rsp)
movq %r12, 168(%rsp)
cfi_offset_rel_rsp (12, 168)
movb %cl, %r12b
movq %r13, 160(%rsp)
cfi_offset_rel_rsp (13, 160)
movl %eax, %r13d
movq %r14, 152(%rsp)
cfi_offset_rel_rsp (14, 152)
movl %edx, %r14d
movq %r15, 144(%rsp)
cfi_offset_rel_rsp (15, 144)
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
movups 112(%rsp), %xmm8
movups 96(%rsp), %xmm9
movups 80(%rsp), %xmm10
movups 64(%rsp), %xmm11
movups 48(%rsp), %xmm12
movups 32(%rsp), %xmm13
movups 16(%rsp), %xmm14
movups (%rsp), %xmm15
movq 136(%rsp), %rsi
movq 128(%rsp), %rdi
movq 168(%rsp), %r12
cfi_restore (%r12)
movq 160(%rsp), %r13
cfi_restore (%r13)
movq 152(%rsp), %r14
cfi_restore (%r14)
movq 144(%rsp), %r15
cfi_restore (%r15)
movups 256(%rsp), %xmm0
jmp .LBL_1_2
.LBL_1_10:
cfi_restore_state
movzbl %r12b, %r15d
shlq $4, %r15
movsd 200(%rsp,%r15), %xmm0
call JUMPTARGET(__log_finite)
movsd %xmm0, 264(%rsp,%r15)
jmp .LBL_1_8
.LBL_1_12:
movzbl %r12b, %r15d
shlq $4, %r15
movsd 192(%rsp,%r15), %xmm0
call JUMPTARGET(__log_finite)
movsd %xmm0, 256(%rsp,%r15)
jmp .LBL_1_7
END (_ZGVbN2v_log_sse4)
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