119 lines
3.9 KiB
NASM
119 lines
3.9 KiB
NASM
dnl PowerPC-32 mpn_modexact_1_odd -- mpn by limb exact remainder.
|
|
|
|
dnl Copyright 2002, 2003, 2005, 2006 Free Software Foundation, Inc.
|
|
dnl
|
|
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
|
|
dnl modify it under the terms of the GNU Lesser General Public License as
|
|
dnl published by the Free Software Foundation; either version 2.1 of the
|
|
dnl License, or (at your option) any later version.
|
|
dnl
|
|
dnl The GNU MP Library is distributed in the hope that it will be useful,
|
|
dnl but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
dnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
dnl Lesser General Public License for more details.
|
|
dnl
|
|
dnl You should have received a copy of the GNU Lesser General Public
|
|
dnl License along with the GNU MP Library; see the file COPYING.LIB. If
|
|
dnl not, write to the Free Software Foundation, Inc., 51 Franklin Street,
|
|
dnl Fifth Floor, Boston, MA 02110-1301, USA.
|
|
|
|
include(`../config.m4')
|
|
|
|
|
|
C cycles/limb
|
|
C 603e: ?
|
|
C 604e: 6.0
|
|
C 75x (G3): 6.0-13.0, depending on divisor
|
|
C 7400,7410 (G4): 6.0-13.0, depending on divisor
|
|
C 744x,745x (G4+): 8.0-10.0, depending on divisor
|
|
C power4/ppc970: 12.0
|
|
C power5: 12.0
|
|
|
|
|
|
C mp_limb_t mpn_modexact_1_odd (mp_srcptr src, mp_size_t size,
|
|
C mp_limb_t divisor);
|
|
C mp_limb_t mpn_modexact_1c_odd (mp_srcptr src, mp_size_t size,
|
|
C mp_limb_t divisor, mp_limb_t carry);
|
|
C
|
|
C For PIC, the inverse is established arithmetically since it measures about
|
|
C 5 cycles faster than the nonsense needed to access modlimb_invert_table in
|
|
C SVR4 or Darwin style PIC. AIX might be better, since it avoids bl/mflr to
|
|
C get at the GOT/TOC/whatever.
|
|
C
|
|
C Using divwu for size==1 measured about 10 cycles slower on 604e, or about
|
|
C 3-5 cycles faster on 750. For now it doesn't seem worth bothering with.
|
|
C
|
|
C The loop allows an early-out on mullw for the inverse, and on mulhwu for
|
|
C the divisor. So the fastest is for instance divisor==1 (inverse==-1), and
|
|
C the slowest is anything giving a full 32-bits in both, such as
|
|
C divisor==0xDEADBEEF (inverse==0x904B300F). These establish the stated
|
|
C range above for 750 and 7400.
|
|
|
|
|
|
ASM_START()
|
|
|
|
EXTERN(modlimb_invert_table)
|
|
|
|
PROLOGUE(mpn_modexact_1_odd)
|
|
li r6, 0
|
|
|
|
PROLOGUE(mpn_modexact_1c_odd)
|
|
|
|
mtctr r4 C size
|
|
|
|
ifdef(`PIC_SLOW',`
|
|
C Load from our table with PIC is so slow on Linux and Darwin that we avoid it
|
|
rlwinm r7, r5, 1,28,28 C (divisor << 1) & 8
|
|
rlwinm r8, r5, 2,28,28 C (divisor << 2) & 8
|
|
xor r7, r7, r8 C ((divisor << 1) ^ (divisor << 2)) & 8
|
|
rlwinm r4, r5, 0,28,31 C divisor low 4 bits, speedup mullw
|
|
xor r4, r4, r7 C inverse, 4 bits
|
|
mullw r7, r4, r4 C i*i
|
|
slwi r4, r4, 1 C 2*i
|
|
rlwinm r8, r5, 0,24,31 C divisor low 8 bits, speedup mullw
|
|
mullw r7, r7, r8 C i*i*d
|
|
sub r4, r4, r7 C inverse, 8 bits
|
|
',`
|
|
LEA( r7, modlimb_invert_table)
|
|
rlwinm r4, r5, 31,25,31 C (divisor/2) & 0x7F
|
|
lbzx r4, r4,r7 C inverse, 8 bits
|
|
')
|
|
|
|
mullw r7, r4, r4 C i*i
|
|
slwi r4, r4, 1 C 2*i
|
|
mullw r7, r5, r7 C i*i*d [i*i is 16 bits, so second operand]
|
|
sub r4, r4, r7 C inverse, 16 bits
|
|
mullw r7, r4, r4 C i*i
|
|
slwi r4, r4, 1 C 2*i
|
|
mullw r7, r7, r5 C i*i*d
|
|
lwz r0, 0(r3) C src[0]
|
|
sub r4, r4, r7 C inverse, 32 bits
|
|
subfc r7, r6, r0 C l = src[0] - carry
|
|
|
|
mullw r7, r7, r4 C q = l * inverse
|
|
bdz L(one)
|
|
|
|
lwzu r0, 4(r3) C src[1]
|
|
mulhwu r6, r7, r5 C carry = high(q*divisor)
|
|
subfe r7, r6, r0 C l = src[1] - carry
|
|
bdz L(two)
|
|
|
|
L(top):
|
|
mullw r7, r7, r4 C q = l * inverse
|
|
lwzu r0, 4(r3) C src[i]
|
|
mulhwu r6, r7, r5 C carry = high(q*divisor)
|
|
subfe r7, r6, r0 C l = src[i] - carry
|
|
bdnz L(top)
|
|
|
|
L(two): mullw r7, r7, r4 C q = l * inverse
|
|
L(one): subfe r3, r3, r3 C ca 0 or -1
|
|
mulhwu r6, r7, r5 C carry = high(q*divisor)
|
|
subf r3, r3, r6 C carry + ca
|
|
blr
|
|
|
|
EPILOGUE(mpn_modexact_1c_odd)
|
|
EPILOGUE(mpn_modexact_1_odd)
|
|
ASM_END()
|