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dnl AMD64 mpn_addlsh_n and mpn_rsblsh_n. R = V2^k +- U.
dnl Copyright 2006, 2010-2012 Free Software Foundation, Inc.
dnl This file is part of the GNU MP Library.
dnl
dnl The GNU MP Library is free software; you can redistribute it and/or modify
dnl it under the terms of either:
dnl
dnl * the GNU Lesser General Public License as published by the Free
dnl Software Foundation; either version 3 of the License, or (at your
dnl option) any later version.
dnl
dnl or
dnl
dnl * the GNU General Public License as published by the Free Software
dnl Foundation; either version 2 of the License, or (at your option) any
dnl later version.
dnl
dnl or both in parallel, as here.
dnl
dnl The GNU MP Library is distributed in the hope that it will be useful, but
dnl WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
dnl or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
dnl for more details.
dnl
dnl You should have received copies of the GNU General Public License and the
dnl GNU Lesser General Public License along with the GNU MP Library. If not,
dnl see https://www.gnu.org/licenses/.
include(`../config.m4')
C cycles/limb
C AMD K8,K9 3.1 < 3.85 for lshift + add_n
C AMD K10 3.1 < 3.85 for lshift + add_n
C Intel P4 14.6 > 7.33 for lshift + add_n
C Intel core2 3.87 > 3.27 for lshift + add_n
C Intel NHM 4 > 3.75 for lshift + add_n
C Intel SBR (5.8) > 3.46 for lshift + add_n
C Intel atom (7.75) < 8.75 for lshift + add_n
C VIA nano 4.7 < 6.25 for lshift + add_n
C This was written quickly and not optimized at all. Surely one could get
C closer to 3 c/l or perhaps even under 3 c/l. Ideas:
C 1) Use indexing to save the 3 LEA
C 2) Write reasonable feed-in code
C 3) Be more clever about register usage
C 4) Unroll more, handling CL negation, carry save/restore cost much now
C 5) Reschedule
C INPUT PARAMETERS
define(`rp', `%rdi')
define(`up', `%rsi')
define(`vp', `%rdx')
define(`n', `%rcx')
define(`cnt', `%r8')
ifdef(`OPERATION_addlsh_n',`
define(ADCSBB, `adc')
define(func, mpn_addlsh_n)
')
ifdef(`OPERATION_rsblsh_n',`
define(ADCSBB, `sbb')
define(func, mpn_rsblsh_n)
')
MULFUNC_PROLOGUE(mpn_addlsh_n mpn_rsblsh_n)
ABI_SUPPORT(DOS64)
ABI_SUPPORT(STD64)
ASM_START()
TEXT
ALIGN(16)
PROLOGUE(func)
FUNC_ENTRY(4)
IFDOS(` mov 56(%rsp), %r8d ')
push %r12
push %r13
push %r14
push %rbp
push %rbx
mov n, %rax
xor R32(%rbx), R32(%rbx) C clear carry save register
mov R32(%r8), R32(%rcx) C shift count
xor R32(%rbp), R32(%rbp) C limb carry
mov R32(%rax), R32(%r11)
and $3, R32(%r11)
je L(4)
sub $1, R32(%r11)
L(012): mov (vp), %r8
mov %r8, %r12
shl R8(%rcx), %r8
or %rbp, %r8
neg R8(%rcx)
mov %r12, %rbp
shr R8(%rcx), %rbp
neg R8(%rcx)
add R32(%rbx), R32(%rbx)
ADCSBB (up), %r8
mov %r8, (rp)
sbb R32(%rbx), R32(%rbx)
lea 8(up), up
lea 8(vp), vp
lea 8(rp), rp
sub $1, R32(%r11)
jnc L(012)
L(4): sub $4, %rax
jc L(end)
ALIGN(16)
L(top): mov (vp), %r8
mov %r8, %r12
mov 8(vp), %r9
mov %r9, %r13
mov 16(vp), %r10
mov %r10, %r14
mov 24(vp), %r11
shl R8(%rcx), %r8
shl R8(%rcx), %r9
shl R8(%rcx), %r10
or %rbp, %r8
mov %r11, %rbp
shl R8(%rcx), %r11
neg R8(%rcx)
shr R8(%rcx), %r12
shr R8(%rcx), %r13
shr R8(%rcx), %r14
shr R8(%rcx), %rbp C used next iteration
or %r12, %r9
or %r13, %r10
or %r14, %r11
neg R8(%rcx)
add R32(%rbx), R32(%rbx) C restore carry flag
ADCSBB (up), %r8
ADCSBB 8(up), %r9
ADCSBB 16(up), %r10
ADCSBB 24(up), %r11
mov %r8, (rp)
mov %r9, 8(rp)
mov %r10, 16(rp)
mov %r11, 24(rp)
sbb R32(%rbx), R32(%rbx) C save carry flag
lea 32(up), up
lea 32(vp), vp
lea 32(rp), rp
sub $4, %rax
jnc L(top)
L(end): add R32(%rbx), R32(%rbx)
ADCSBB $0, %rbp
mov %rbp, %rax
pop %rbx
pop %rbp
pop %r14
pop %r13
pop %r12
FUNC_EXIT()
ret
EPILOGUE()
|