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()
