| dnl Intel Pentium 4 mpn_mod_34lsub1 -- remainder modulo 2^24-1. |
| |
| dnl Copyright 2000, 2001, 2002, 2003 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 Pentium4: 1.0 cycles/limb |
| |
| |
| C mp_limb_t mpn_mod_34lsub1 (mp_srcptr src, mp_size_t size) |
| C |
| C Enhancements: |
| C |
| C There might a couple of cycles to save by using plain integer code for |
| C more small sizes. 2 limbs measures about 20 cycles, but 3 limbs jumps to |
| C about 46 (inclusive of some function call overheads). |
| |
| defframe(PARAM_SIZE, 8) |
| defframe(PARAM_SRC, 4) |
| |
| dnl re-use parameter space |
| define(SAVE_EBX, `PARAM_SRC') |
| define(SAVE_ESI, `PARAM_SIZE') |
| |
| TEXT |
| ALIGN(16) |
| PROLOGUE(mpn_mod_34lsub1) |
| deflit(`FRAME',0) |
| |
| movl PARAM_SIZE, %ecx |
| movl PARAM_SRC, %edx |
| movl (%edx), %eax |
| |
| subl $2, %ecx |
| ja L(three_or_more) |
| jne L(one) |
| |
| movl 4(%edx), %edx |
| movl %eax, %ecx |
| shrl $24, %eax C src[0] high |
| |
| andl $0x00FFFFFF, %ecx C src[0] low |
| addl %ecx, %eax |
| |
| movl %edx, %ecx |
| shll $8, %edx |
| |
| shrl $16, %ecx C src[1] low |
| addl %ecx, %eax |
| |
| andl $0x00FFFF00, %edx C src[1] high |
| addl %edx, %eax |
| |
| L(one): |
| ret |
| |
| |
| L(three_or_more): |
| pxor %mm0, %mm0 |
| pxor %mm1, %mm1 |
| pxor %mm2, %mm2 |
| |
| pcmpeqd %mm7, %mm7 |
| psrlq $32, %mm7 C 0x00000000FFFFFFFF, low 32 bits |
| |
| pcmpeqd %mm6, %mm6 |
| psrlq $40, %mm6 C 0x0000000000FFFFFF, low 24 bits |
| |
| L(top): |
| C eax |
| C ebx |
| C ecx counter, size-2 to 0, -1 or -2 |
| C edx src, incrementing |
| C |
| C mm0 sum 0mod3 |
| C mm1 sum 1mod3 |
| C mm2 sum 2mod3 |
| C mm3 |
| C mm4 |
| C mm5 |
| C mm6 0x0000000000FFFFFF |
| C mm7 0x00000000FFFFFFFF |
| |
| movd (%edx), %mm3 |
| paddq %mm3, %mm0 |
| |
| movd 4(%edx), %mm3 |
| paddq %mm3, %mm1 |
| |
| movd 8(%edx), %mm3 |
| paddq %mm3, %mm2 |
| |
| addl $12, %edx |
| subl $3, %ecx |
| ja L(top) |
| |
| |
| C ecx is -2, -1 or 0 representing 0, 1 or 2 more limbs, respectively |
| |
| addl $1, %ecx |
| js L(combine) C 0 more |
| |
| movd (%edx), %mm3 |
| paddq %mm3, %mm0 |
| |
| jz L(combine) C 1 more |
| |
| movd 4(%edx), %mm3 |
| paddq %mm3, %mm1 |
| |
| L(combine): |
| movq %mm7, %mm3 C low halves |
| pand %mm0, %mm3 |
| |
| movq %mm7, %mm4 |
| pand %mm1, %mm4 |
| |
| movq %mm7, %mm5 |
| pand %mm2, %mm5 |
| |
| psrlq $32, %mm0 C high halves |
| psrlq $32, %mm1 |
| psrlq $32, %mm2 |
| |
| paddq %mm0, %mm4 C fold high halves to give 33 bits each |
| paddq %mm1, %mm5 |
| paddq %mm2, %mm3 |
| |
| psllq $8, %mm4 C combine at respective offsets |
| psllq $16, %mm5 |
| paddq %mm4, %mm3 |
| paddq %mm5, %mm3 C 0x000cxxxxxxxxxxxx, 50 bits |
| |
| pand %mm3, %mm6 C fold at 24 bits |
| psrlq $24, %mm3 |
| |
| paddq %mm6, %mm3 |
| movd %mm3, %eax |
| |
| ASSERT(z, C nothing left in high dword |
| `psrlq $32, %mm3 |
| movd %mm3, %ecx |
| orl %ecx, %ecx') |
| |
| emms |
| ret |
| |
| EPILOGUE() |
