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dnl PowerPC-64/mode32 mpn_sub_n -- Subtract two limb vectors of the same
dnl length and store difference in a third limb vector.
dnl Copyright 1999, 2000, 2001, 2003, 2005 Free Software Foundation, Inc.
dnl This file is part of the GNU MP Library.
dnl The GNU MP Library is free software; you can redistribute it and/or modify
dnl it under the terms of the GNU Lesser General Public License as published
dnl by the Free Software Foundation; either version 2.1 of the License, or (at
dnl your option) any later version.
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 Lesser General Public
dnl License for more details.
dnl You should have received a copy of the GNU Lesser General Public License
dnl along with the GNU MP Library; see the file COPYING.LIB. If not, write
dnl to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
dnl Boston, MA 02110-1301, USA.
include(`../config.m4')
C cycles/limb
C POWER3/PPC630: ?
C POWER4/PPC970: 4.25
C INPUT PARAMETERS
C rp r3
C up r4
C vp r5
C n r6
ASM_START()
PROLOGUE(mpn_sub_n)
mtctr r6 C copy size into CTR
addic r0, r6, -1 C set cy
ld r8, 0(r4) C load least significant s1 limb
ld r0, 0(r5) C load least significant s2 limb
addi r3, r3, -8 C offset res_ptr, it's updated before it's used
bdz L(end) C If done, skip loop
L(oop): ld r9, 8(r4) C load s1 limb
ld r10, 8(r5) C load s2 limb
subfe r7, r0, r8 C subtract limbs with cy, set cy
srdi r6, r0, 32
srdi r11, r8, 32
subfe r6, r6, r11
std r7, 8(r3) C store result limb
bdz L(exit) C decrement CTR and exit if done
ldu r8, 16(r4) C load s1 limb and update s1_ptr
ldu r0, 16(r5) C load s2 limb and update s2_ptr
subfe r7, r10, r9 C subtract limbs with cy, set cy
srdi r6, r10, 32
srdi r11, r9, 32
subfe r6, r6, r11
stdu r7, 16(r3) C store result limb and update res_ptr
bdnz L(oop) C decrement CTR and loop back
L(end): subfe r7, r0, r8
srdi r6, r0, 32
srdi r11, r8, 32
subfe r6, r6, r11
std r7, 8(r3) C store ultimate result limb
subfe r3, r0, r0 C load !cy into ...
subfic r4, r3, 0 C ... return value register
li r3, 0 C zero extend return value
blr
L(exit): subfe r7, r10, r9
srdi r6, r10, 32
srdi r11, r9, 32
subfe r6, r6, r11
std r7, 16(r3)
subfe r3, r0, r0 C load !cy into ...
subfic r4, r3, 0 C ... return value register
li r3, 0 C zero extend return value
blr
EPILOGUE()
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