dnl AMD64 mpn_lshift optimised for CPUs with fast SSE.
dnl Contributed to the GNU project by David Harvey and Torbjorn Granlund.
dnl Copyright 2010-2012, 2018 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 cycles/limb good
C 16-byte aligned 16-byte unaligned for cpu?
C AMD K8,K9 ? ?
C AMD K10 1.68 (1.45) 1.75 (1.49) Y
C AMD bd1 1.82 (1.75) 1.82 (1.75) Y
C AMD bobcat 4 4
C Intel P4 3 (2.7) 3 (2.7) Y
C Intel core2 2.05 (1.67) 2.55 (1.75)
C Intel NHM 2.05 (1.75) 2.09 (2)
C Intel SBR 1.5 (1.3125) 1.5 (1.4375) Y
C Intel atom ? ?
C VIA nano 2.25 (2) 2.5 (2) Y
C We try to do as many 16-byte operations as possible. The top-most and
C bottom-most writes might need 8-byte operations.
C There are two inner-loops, one for when rp = ap (mod 16) and one when this is
C not true. The aligned case reads 16+8 bytes, the unaligned case reads
C 16+8+X bytes, where X is 8 or 16 depending on how punpcklqdq is implemented.
C This is not yet great code:
C (1) The unaligned case makes many reads.
C (2) We should do some unrolling, at least 2-way.
C With 2-way unrolling but no scheduling we reach 1.5 c/l on K10 and 2 c/l on
C Nano.
C INPUT PARAMETERS
define(`rp', `%rdi')
define(`ap', `%rsi')
define(`n', `%rdx')
define(`cnt', `%rcx')
ASM_START()
TEXT
ALIGN(64)
PROLOGUE(mpn_lshift)
FUNC_ENTRY(4)
movd R32(%rcx), %xmm4
mov $64, R32(%rax)
sub R32(%rcx), R32(%rax)
movd R32(%rax), %xmm5
neg R32(%rcx)
mov -8(ap,n,8), %rax
shr R8(%rcx), %rax
cmp $2, n
jle L(le2)
lea (rp,n,8), R32(%rcx)
test $8, R8(%rcx)
je L(rp_aligned)
C Do one initial limb in order to make rp aligned
movq -8(ap,n,8), %xmm0
movq -16(ap,n,8), %xmm1
psllq %xmm4, %xmm0
psrlq %xmm5, %xmm1
por %xmm1, %xmm0
movq %xmm0, -8(rp,n,8)
dec n
L(rp_aligned):
lea (ap,n,8), R32(%rcx)
test $8, R8(%rcx)
je L(aent)
jmp L(uent)
C *****************************************************************************
C Handle the case when ap != rp (mod 16).
ALIGN(16)
L(utop):movdqa -8(ap,n,8), %xmm0
movq (ap,n,8), %xmm1
punpcklqdq 8(ap,n,8), %xmm1
psllq %xmm4, %xmm1
psrlq %xmm5, %xmm0
por %xmm1, %xmm0
movdqa %xmm0, (rp,n,8)
L(uent):sub $2, n
ja L(utop)
jne L(end8)
movq (ap), %xmm1
pxor %xmm0, %xmm0
punpcklqdq %xmm1, %xmm0
punpcklqdq 8(ap), %xmm1
psllq %xmm4, %xmm1
psrlq %xmm5, %xmm0
por %xmm1, %xmm0
movdqa %xmm0, (rp)
FUNC_EXIT()
ret
C *****************************************************************************
C Handle the case when ap = rp (mod 16).
ALIGN(16)
L(atop):movdqa (ap,n,8), %xmm0 C xmm0 = B*ap[n-1] + ap[n-2]
movq -8(ap,n,8), %xmm1 C xmm1 = ap[n-3]
punpcklqdq %xmm0, %xmm1 C xmm1 = B*ap[n-2] + ap[n-3]
psllq %xmm4, %xmm0
psrlq %xmm5, %xmm1
por %xmm1, %xmm0
movdqa %xmm0, (rp,n,8)
L(aent):
sub $2, n
ja L(atop)
jne L(end8)
movdqa (ap), %xmm1
pxor %xmm0, %xmm0
punpcklqdq %xmm1, %xmm0
psllq %xmm4, %xmm1
psrlq %xmm5, %xmm0
por %xmm1, %xmm0
movdqa %xmm0, (rp)
FUNC_EXIT()
ret
C *****************************************************************************
ALIGN(16)
L(le2): jne L(end8)
movq 8(ap), %xmm0
movq (ap), %xmm1
psllq %xmm4, %xmm0
psrlq %xmm5, %xmm1
por %xmm1, %xmm0
movq %xmm0, 8(rp)
L(end8):movq (ap), %xmm0
psllq %xmm4, %xmm0
movq %xmm0, (rp)
FUNC_EXIT()
ret
EPILOGUE()