mode1o.asm revision 1.1.1.3
1 dnl Intel Pentium-4 mpn_modexact_1_odd -- mpn by limb exact remainder. 2 3 dnl Copyright 2001, 2002, 2007 Free Software Foundation, Inc. 4 5 dnl This file is part of the GNU MP Library. 6 dnl 7 dnl The GNU MP Library is free software; you can redistribute it and/or modify 8 dnl it under the terms of either: 9 dnl 10 dnl * the GNU Lesser General Public License as published by the Free 11 dnl Software Foundation; either version 3 of the License, or (at your 12 dnl option) any later version. 13 dnl 14 dnl or 15 dnl 16 dnl * the GNU General Public License as published by the Free Software 17 dnl Foundation; either version 2 of the License, or (at your option) any 18 dnl later version. 19 dnl 20 dnl or both in parallel, as here. 21 dnl 22 dnl The GNU MP Library is distributed in the hope that it will be useful, but 23 dnl WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 24 dnl or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 25 dnl for more details. 26 dnl 27 dnl You should have received copies of the GNU General Public License and the 28 dnl GNU Lesser General Public License along with the GNU MP Library. If not, 29 dnl see https://www.gnu.org/licenses/. 30 31 include(`../config.m4') 32 33 34 C P4: 19.0 cycles/limb 35 36 37 C mp_limb_t mpn_modexact_1_odd (mp_srcptr src, mp_size_t size, 38 C mp_limb_t divisor); 39 C mp_limb_t mpn_modexact_1c_odd (mp_srcptr src, mp_size_t size, 40 C mp_limb_t divisor, mp_limb_t carry); 41 C 42 43 defframe(PARAM_CARRY, 16) 44 defframe(PARAM_DIVISOR,12) 45 defframe(PARAM_SIZE, 8) 46 defframe(PARAM_SRC, 4) 47 48 TEXT 49 50 ALIGN(16) 51 PROLOGUE(mpn_modexact_1c_odd) 52 deflit(`FRAME',0) 53 54 movd PARAM_CARRY, %mm1 55 jmp L(start_1c) 56 57 EPILOGUE() 58 59 60 ALIGN(16) 61 PROLOGUE(mpn_modexact_1_odd) 62 deflit(`FRAME',0) 63 64 pxor %mm1, %mm1 C carry limb 65 L(start_1c): 66 movl PARAM_DIVISOR, %eax 67 68 movd PARAM_DIVISOR, %mm7 69 70 shrl %eax 71 72 andl $127, %eax C d/2, 7 bits 73 74 ifdef(`PIC',` 75 LEA( binvert_limb_table, %edx) 76 movzbl (%eax,%edx), %eax C inv 8 bits 77 ',` 78 movzbl binvert_limb_table(%eax), %eax C inv 8 bits 79 ') 80 81 C 82 83 movd %eax, %mm6 C inv 84 85 movd %eax, %mm0 C inv 86 87 pmuludq %mm6, %mm6 C inv*inv 88 89 C 90 91 pmuludq %mm7, %mm6 C inv*inv*d 92 paddd %mm0, %mm0 C 2*inv 93 94 C 95 96 psubd %mm6, %mm0 C inv = 2*inv - inv*inv*d 97 pxor %mm6, %mm6 98 99 paddd %mm0, %mm6 100 pmuludq %mm0, %mm0 C inv*inv 101 102 C 103 104 pmuludq %mm7, %mm0 C inv*inv*d 105 paddd %mm6, %mm6 C 2*inv 106 107 108 movl PARAM_SRC, %eax 109 movl PARAM_SIZE, %ecx 110 111 C 112 113 psubd %mm0, %mm6 C inv = 2*inv - inv*inv*d 114 115 ASSERT(e,` C expect d*inv == 1 mod 2^GMP_LIMB_BITS 116 pushl %eax FRAME_pushl() 117 movd %mm6, %eax 118 imul PARAM_DIVISOR, %eax 119 cmpl $1, %eax 120 popl %eax FRAME_popl()') 121 122 pxor %mm0, %mm0 C carry bit 123 124 125 C The dependent chain here is as follows. 126 C 127 C latency 128 C psubq s = (src-cbit) - climb 2 129 C pmuludq q = s*inverse 8 130 C pmuludq prod = q*divisor 8 131 C psrlq climb = high(prod) 2 132 C -- 133 C 20 134 C 135 C Yet the loop measures 19.0 c/l, so obviously there's something gained 136 C there over a straight reading of the chip documentation. 137 138 L(top): 139 C eax src, incrementing 140 C ebx 141 C ecx counter, limbs 142 C edx 143 C 144 C mm0 carry bit 145 C mm1 carry limb 146 C mm6 inverse 147 C mm7 divisor 148 149 movd (%eax), %mm2 150 addl $4, %eax 151 152 psubq %mm0, %mm2 C src - cbit 153 154 psubq %mm1, %mm2 C src - cbit - climb 155 movq %mm2, %mm0 156 psrlq $63, %mm0 C new cbit 157 158 pmuludq %mm6, %mm2 C s*inverse 159 160 movq %mm7, %mm1 161 pmuludq %mm2, %mm1 C q*divisor 162 psrlq $32, %mm1 C new climb 163 164 subl $1, %ecx 165 jnz L(top) 166 167 168 L(done): 169 paddq %mm1, %mm0 170 movd %mm0, %eax 171 emms 172 ret 173 174 EPILOGUE() 175 ASM_END() 176
Indexes created Wed Apr 29 00:23:26 UTC 2026