1; mc88100 __gmpn_mul_1 -- Multiply a limb vector with a single limb and 2; store the product in a second limb vector. 3 4; Copyright 1992, 1994, 1995, 2000 Free Software Foundation, Inc. 5 6; This file is part of the GNU MP Library. 7; 8; The GNU MP Library is free software; you can redistribute it and/or modify 9; it under the terms of either: 10; 11; * the GNU Lesser General Public License as published by the Free 12; Software Foundation; either version 3 of the License, or (at your 13; option) any later version. 14; 15; or 16; 17; * the GNU General Public License as published by the Free Software 18; Foundation; either version 2 of the License, or (at your option) any 19; later version. 20; 21; or both in parallel, as here. 22; 23; The GNU MP Library is distributed in the hope that it will be useful, but 24; WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 25; or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 26; for more details. 27; 28; You should have received copies of the GNU General Public License and the 29; GNU Lesser General Public License along with the GNU MP Library. If not, 30; see https://www.gnu.org/licenses/. 31 32 33; INPUT PARAMETERS 34; res_ptr r2 35; s1_ptr r3 36; size r4 37; s2_limb r5 38 39; Common overhead is about 11 cycles/invocation. 40 41; The speed for S2_LIMB >= 0x10000 is approximately 21 cycles/limb. (The 42; pipeline stalls 2 cycles due to WB contention.) 43 44; The speed for S2_LIMB < 0x10000 is approximately 16 cycles/limb. (The 45; pipeline stalls 2 cycles due to WB contention and 1 cycle due to latency.) 46 47; To enhance speed: 48; 1. Unroll main loop 4-8 times. 49; 2. Schedule code to avoid WB contention. It might be tempting to move the 50; ld instruction in the loops down to save 2 cycles (less WB contention), 51; but that looses because the ultimate value will be read from outside 52; the allocated space. But if we handle the ultimate multiplication in 53; the tail, we can do this. 54; 3. Make the multiplication with less instructions. I think the code for 55; (S2_LIMB >= 0x10000) is not minimal. 56; With these techniques the (S2_LIMB >= 0x10000) case would run in 17 or 57; less cycles/limb; the (S2_LIMB < 0x10000) case would run in 11 58; cycles/limb. (Assuming infinite unrolling.) 59 60 text 61 align 16 62 global ___gmpn_mul_1 63___gmpn_mul_1: 64 65 ; Make S1_PTR and RES_PTR point at the end of their blocks 66 ; and negate SIZE. 67 lda r3,r3[r4] 68 lda r6,r2[r4] ; RES_PTR in r6 since r2 is retval 69 subu r4,r0,r4 70 71 addu.co r2,r0,r0 ; r2 = cy = 0 72 ld r9,r3[r4] 73 mask r7,r5,0xffff ; r7 = lo(S2_LIMB) 74 extu r8,r5,16 ; r8 = hi(S2_LIMB) 75 bcnd.n eq0,r8,Lsmall ; jump if (hi(S2_LIMB) == 0) 76 subu r6,r6,4 77 78; General code for any value of S2_LIMB. 79 80 ; Make a stack frame and save r25 and r26 81 subu r31,r31,16 82 st.d r25,r31,8 83 84 ; Enter the loop in the middle 85 br.n L1 86 addu r4,r4,1 87 88Loop: ld r9,r3[r4] 89 st r26,r6[r4] 90; bcnd ne0,r0,0 ; bubble 91 addu r4,r4,1 92L1: mul r26,r9,r5 ; low word of product mul_1 WB ld 93 mask r12,r9,0xffff ; r12 = lo(s1_limb) mask_1 94 mul r11,r12,r7 ; r11 = prod_0 mul_2 WB mask_1 95 mul r10,r12,r8 ; r10 = prod_1a mul_3 96 extu r13,r9,16 ; r13 = hi(s1_limb) extu_1 WB mul_1 97 mul r12,r13,r7 ; r12 = prod_1b mul_4 WB extu_1 98 mul r25,r13,r8 ; r25 = prod_2 mul_5 WB mul_2 99 extu r11,r11,16 ; r11 = hi(prod_0) extu_2 WB mul_3 100 addu r10,r10,r11 ; addu_1 WB extu_2 101; bcnd ne0,r0,0 ; bubble WB addu_1 102 addu.co r10,r10,r12 ; WB mul_4 103 mask.u r10,r10,0xffff ; move the 16 most significant bits... 104 addu.ci r10,r10,r0 ; ...to the low half of the word... 105 rot r10,r10,16 ; ...and put carry in pos 16. 106 addu.co r26,r26,r2 ; add old carry limb 107 bcnd.n ne0,r4,Loop 108 addu.ci r2,r25,r10 ; compute new carry limb 109 110 st r26,r6[r4] 111 ld.d r25,r31,8 112 jmp.n r1 113 addu r31,r31,16 114 115; Fast code for S2_LIMB < 0x10000 116Lsmall: 117 ; Enter the loop in the middle 118 br.n SL1 119 addu r4,r4,1 120 121SLoop: ld r9,r3[r4] ; 122 st r8,r6[r4] ; 123 addu r4,r4,1 ; 124SL1: mul r8,r9,r5 ; low word of product 125 mask r12,r9,0xffff ; r12 = lo(s1_limb) 126 extu r13,r9,16 ; r13 = hi(s1_limb) 127 mul r11,r12,r7 ; r11 = prod_0 128 mul r12,r13,r7 ; r12 = prod_1b 129 addu.cio r8,r8,r2 ; add old carry limb 130 extu r10,r11,16 ; r11 = hi(prod_0) 131 addu r10,r10,r12 ; 132 bcnd.n ne0,r4,SLoop 133 extu r2,r10,16 ; r2 = new carry limb 134 135 jmp.n r1 136 st r8,r6[r4] 137