1/* Alpha 21064 mpih-mul1.S -- Multiply a limb vector with a limb and store 2 * the result in a second limb vector. 3 * 4 * Copyright (C) 1992, 1994, 1995, 1998, 5 * 2001, 2002 Free Software Foundation, Inc. 6 * 7 * This file is part of Libgcrypt. 8 * 9 * Libgcrypt is free software; you can redistribute it and/or modify 10 * it under the terms of the GNU Lesser General Public License as 11 * published by the Free Software Foundation; either version 2.1 of 12 * the License, or (at your option) any later version. 13 * 14 * Libgcrypt is distributed in the hope that it will be useful, 15 * but WITHOUT ANY WARRANTY; without even the implied warranty of 16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 * GNU Lesser General Public License for more details. 18 * 19 * You should have received a copy of the GNU Lesser General Public 20 * License along with this program; if not, write to the Free Software 21 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA 22 */ 23 24 25/******************* 26 * mpi_limb_t 27 * _gcry_mpih_mul_1( mpi_ptr_t res_ptr, (r16) 28 * mpi_ptr_t s1_ptr, (r17) 29 * mpi_size_t s1_size, (r18) 30 * mpi_limb_t s2_limb) (r19) 31 * 32 * This code runs at 42 cycles/limb on the EV4 and 18 cycles/limb on the EV5. 33 * 34 * To improve performance for long multiplications, we would use 35 * 'fetch' for S1 and 'fetch_m' for RES. It's not obvious how to use 36 * these instructions without slowing down the general code: 1. We can 37 * only have two prefetches in operation at any time in the Alpha 38 * architecture. 2. There will seldom be any special alignment 39 * between RES_PTR and S1_PTR. Maybe we can simply divide the current 40 * loop into an inner and outer loop, having the inner loop handle 41 * exactly one prefetch block? 42 */ 43 44 .set noreorder 45 .set noat 46.text 47 .align 3 48 .globl _gcry_mpih_mul_1 49 .ent _gcry_mpih_mul_1 2 50_gcry_mpih_mul_1: 51 .frame $30,0,$26 52 53 ldq $2,0($17) # $2 = s1_limb 54 subq $18,1,$18 # size-- 55 mulq $2,$19,$3 # $3 = prod_low 56 bic $31,$31,$4 # clear cy_limb 57 umulh $2,$19,$0 # $0 = prod_high 58 beq $18,Lend1 # jump if size was == 1 59 ldq $2,8($17) # $2 = s1_limb 60 subq $18,1,$18 # size-- 61 stq $3,0($16) 62 beq $18,Lend2 # jump if size was == 2 63 64 .align 3 65Loop: mulq $2,$19,$3 # $3 = prod_low 66 addq $4,$0,$0 # cy_limb = cy_limb + 'cy' 67 subq $18,1,$18 # size-- 68 umulh $2,$19,$4 # $4 = cy_limb 69 ldq $2,16($17) # $2 = s1_limb 70 addq $17,8,$17 # s1_ptr++ 71 addq $3,$0,$3 # $3 = cy_limb + prod_low 72 stq $3,8($16) 73 cmpult $3,$0,$0 # $0 = carry from (cy_limb + prod_low) 74 addq $16,8,$16 # res_ptr++ 75 bne $18,Loop 76 77Lend2: mulq $2,$19,$3 # $3 = prod_low 78 addq $4,$0,$0 # cy_limb = cy_limb + 'cy' 79 umulh $2,$19,$4 # $4 = cy_limb 80 addq $3,$0,$3 # $3 = cy_limb + prod_low 81 cmpult $3,$0,$0 # $0 = carry from (cy_limb + prod_low) 82 stq $3,8($16) 83 addq $4,$0,$0 # cy_limb = prod_high + cy 84 ret $31,($26),1 85Lend1: stq $3,0($16) 86 ret $31,($26),1 87 88 .end _gcry_mpih_mul_1 89 90 91