| dnl Intel P6 mpn_mod_34lsub1 -- remainder modulo 2^24-1. |
| |
| dnl Copyright 2000, 2001, 2002, 2004 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 3 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 License |
| dnl along with the GNU MP Library. If not, see http://www.gnu.org/licenses/. |
| |
| include(`../config.m4') |
| |
| |
| C P6: 2.0 cycles/limb |
| |
| C TODO |
| C Experiments with more unrolling indicate that 1.5 c/l is possible on P6-13 |
| C with the current carry handling scheme. |
| |
| C mp_limb_t mpn_mod_34lsub1 (mp_srcptr src, mp_size_t size) |
| C |
| C Groups of three limbs are handled, with carry bits from 0mod3 into 1mod3 |
| C into 2mod3, but at that point going into a separate carries total so we |
| C don't keep the carry flag live across the loop control. Avoiding decl |
| C lets us get to 2.0 c/l, as compared to the generic x86 code at 3.66. |
| C |
| |
| defframe(PARAM_SIZE, 8) |
| defframe(PARAM_SRC, 4) |
| |
| dnl re-use parameter space |
| define(SAVE_EBX, `PARAM_SIZE') |
| define(SAVE_ESI, `PARAM_SRC') |
| |
| TEXT |
| ALIGN(16) |
| PROLOGUE(mpn_mod_34lsub1) |
| deflit(`FRAME',0) |
| |
| movl PARAM_SIZE, %ecx |
| movl PARAM_SRC, %edx |
| |
| subl $2, %ecx C size-2 |
| movl (%edx), %eax C src[0] |
| ja L(three_or_more) |
| jb L(one) |
| |
| C size==2 |
| |
| movl 4(%edx), %ecx C src[1] |
| |
| movl %eax, %edx C src[0] |
| shrl $24, %eax C src[0] high |
| |
| andl $0xFFFFFF, %edx C src[0] low |
| |
| addl %edx, %eax |
| movl %ecx, %edx C src[1] |
| shrl $16, %ecx C src[1] high |
| |
| andl $0xFFFF, %edx |
| addl %ecx, %eax |
| |
| shll $8, %edx C src[1] low |
| |
| addl %edx, %eax |
| L(one): |
| ret |
| |
| |
| L(three_or_more): |
| C eax src[0], initial acc 0mod3 |
| C ebx |
| C ecx size-2 |
| C edx src |
| C esi |
| C edi |
| C ebp |
| |
| movl %ebx, SAVE_EBX |
| movl 4(%edx), %ebx C src[1], initial 1mod3 |
| subl $3, %ecx C size-5 |
| |
| movl %esi, SAVE_ESI |
| movl 8(%edx), %esi C src[2], initial 2mod3 |
| |
| pushl %edi FRAME_pushl() |
| movl $0, %edi C initial carries 0mod3 |
| jng L(done) C if size < 6 |
| |
| |
| L(top): |
| C eax acc 0mod3 |
| C ebx acc 1mod3 |
| C ecx counter, limbs |
| C edx src |
| C esi acc 2mod3 |
| C edi carrys into 0mod3 |
| C ebp |
| |
| addl 12(%edx), %eax |
| adcl 16(%edx), %ebx |
| adcl 20(%edx), %esi |
| leal 12(%edx), %edx |
| adcl $0, %edi |
| |
| subl $3, %ecx |
| jg L(top) C at least 3 more to process |
| |
| |
| L(done): |
| C ecx is -2, -1 or 0 representing 0, 1 or 2 more limbs respectively |
| cmpl $-1, %ecx |
| jl L(done_0) C if -2, meaning 0 more limbs |
| |
| C 1 or 2 more limbs |
| movl $0, %ecx |
| je L(done_1) C if -1, meaning 1 more limb only |
| movl 16(%edx), %ecx |
| L(done_1): |
| addl 12(%edx), %eax C 0mod3 |
| adcl %ecx, %ebx C 1mod3 |
| adcl $0, %esi C 2mod3 |
| adcl $0, %edi C carries 0mod3 |
| |
| L(done_0): |
| C eax acc 0mod3 |
| C ebx acc 1mod3 |
| C ecx |
| C edx |
| C esi acc 2mod3 |
| C edi carries 0mod3 |
| C ebp |
| |
| movl %eax, %ecx C 0mod3 |
| shrl $24, %eax C 0mod3 high initial total |
| |
| andl $0xFFFFFF, %ecx C 0mod3 low |
| movl %edi, %edx C carries |
| shrl $24, %edi C carries high |
| |
| addl %ecx, %eax C add 0mod3 low |
| andl $0xFFFFFF, %edx C carries 0mod3 low |
| movl %ebx, %ecx C 1mod3 |
| |
| shrl $16, %ebx C 1mod3 high |
| addl %edi, %eax C add carries high |
| addl %edx, %eax C add carries 0mod3 low |
| |
| andl $0xFFFF, %ecx C 1mod3 low mask |
| addl %ebx, %eax C add 1mod3 high |
| movl SAVE_EBX, %ebx |
| |
| shll $8, %ecx C 1mod3 low |
| movl %esi, %edx C 2mod3 |
| popl %edi FRAME_popl() |
| |
| shrl $8, %esi C 2mod3 high |
| andl $0xFF, %edx C 2mod3 low mask |
| addl %ecx, %eax C add 1mod3 low |
| |
| shll $16, %edx C 2mod3 low |
| addl %esi, %eax C add 2mod3 high |
| movl SAVE_ESI, %esi |
| |
| addl %edx, %eax C add 2mod3 low |
| |
| ret |
| |
| EPILOGUE() |