dnl Intel P6 mpn_lshsub_n -- mpn papillion support.
dnl Copyright 2006 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 P6/13: 3.35 cycles/limb (separate mpn_sub_n + mpn_lshift needs 4.12)
C (1) The loop is not scheduled in any way, and scheduling attempts have not
C improved speed on P6/13. Presumably, the K7 will want scheduling, if it
C at all wants to use MMX.
C (2) We could save a register by not alternatingly using eax and edx in the
C loop.
define(`rp', `%edi')
define(`up', `%esi')
define(`vp', `%ebx')
define(`n', `%ecx')
define(`cnt', `%mm7')
ASM_START()
TEXT
ALIGN(16)
PROLOGUE(mpn_lshsub_n)
push %edi
push %esi
push %ebx
mov 16(%esp), rp
mov 20(%esp), up
mov 24(%esp), vp
mov 28(%esp), n
mov $32, %eax
sub 32(%esp), %eax
movd %eax, cnt
lea (up,n,4), up
lea (vp,n,4), vp
lea (rp,n,4), rp
neg n
mov n, %eax
and $-8, n
and $7, %eax
shl %eax C eax = 2x
lea (%eax,%eax,4), %edx C edx = 10x
ifdef(`PIC',`
call L(pic_calc)
L(here):
',`
lea L(ent)(%eax,%edx,2), %eax C eax = 22x
')
pxor %mm1, %mm1
pxor %mm0, %mm0
jmp *%eax
ifdef(`PIC',`
L(pic_calc):
C See mpn/x86/README about old gas bugs
lea (%eax,%edx,2), %eax
add $L(ent)-L(here), %eax
add (%esp), %eax
ret_internal
')
L(end): C compute (cy<<cnt) | (edx>>(32-cnt))
sbb %eax, %eax
neg %eax
mov 32(%esp), %ecx
shld %cl, %edx, %eax
emms
pop %ebx
pop %esi
pop %edi
ret
ALIGN(16)
L(top): jecxz L(end)
L(ent): mov 0(up,n,4), %eax
sbb 0(vp,n,4), %eax
movd %eax, %mm0
punpckldq %mm0, %mm1
psrlq %mm7, %mm1
movd %mm1, 0(rp,n,4)
mov 4(up,n,4), %edx
sbb 4(vp,n,4), %edx
movd %edx, %mm1
punpckldq %mm1, %mm0
psrlq %mm7, %mm0
movd %mm0, 4(rp,n,4)
mov 8(up,n,4), %eax
sbb 8(vp,n,4), %eax
movd %eax, %mm0
punpckldq %mm0, %mm1
psrlq %mm7, %mm1
movd %mm1, 8(rp,n,4)
mov 12(up,n,4), %edx
sbb 12(vp,n,4), %edx
movd %edx, %mm1
punpckldq %mm1, %mm0
psrlq %mm7, %mm0
movd %mm0, 12(rp,n,4)
mov 16(up,n,4), %eax
sbb 16(vp,n,4), %eax
movd %eax, %mm0
punpckldq %mm0, %mm1
psrlq %mm7, %mm1
movd %mm1, 16(rp,n,4)
mov 20(up,n,4), %edx
sbb 20(vp,n,4), %edx
movd %edx, %mm1
punpckldq %mm1, %mm0
psrlq %mm7, %mm0
movd %mm0, 20(rp,n,4)
mov 24(up,n,4), %eax
sbb 24(vp,n,4), %eax
movd %eax, %mm0
punpckldq %mm0, %mm1
psrlq %mm7, %mm1
movd %mm1, 24(rp,n,4)
mov 28(up,n,4), %edx
sbb 28(vp,n,4), %edx
movd %edx, %mm1
punpckldq %mm1, %mm0
psrlq %mm7, %mm0
movd %mm0, 28(rp,n,4)
lea 8(n), n
jmp L(top)
EPILOGUE()