# Alpha __mpn_sub_n -- Subtract two limb vectors of the same length > 0 and # store difference in a third limb vector. # Copyright (C) 1995 Free Software Foundation, Inc. # This file is part of the GNU MP Library. # The GNU MP Library is free software; you can redistribute it and/or modify # it under the terms of the GNU Lesser General Public License as published by # the Free Software Foundation; either version 2.1 of the License, or (at your # option) any later version. # The GNU MP Library is distributed in the hope that it will be useful, but # WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY # or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public # License for more details. # You should have received a copy of the GNU Lesser General Public License # along with the GNU MP Library. If not, see . # INPUT PARAMETERS # res_ptr $16 # s1_ptr $17 # s2_ptr $18 # size $19 .set noreorder .set noat .text .align 3 .globl __mpn_sub_n .ent __mpn_sub_n __mpn_sub_n: .frame $30,0,$26,0 or $31,$31,$25 # clear cy subq $19,4,$19 # decr loop cnt blt $19,.Lend2 # if less than 4 limbs, goto 2nd loop # Start software pipeline for 1st loop ldq $0,0($18) ldq $1,8($18) ldq $4,0($17) ldq $5,8($17) addq $17,32,$17 # update s1_ptr ldq $2,16($18) subq $4,$0,$20 # 1st main sub ldq $3,24($18) subq $19,4,$19 # decr loop cnt ldq $6,-16($17) cmpult $4,$20,$25 # compute cy from last sub ldq $7,-8($17) addq $1,$25,$28 # cy add addq $18,32,$18 # update s2_ptr subq $5,$28,$21 # 2nd main sub cmpult $28,$25,$8 # compute cy from last add blt $19,.Lend1 # if less than 4 limbs remain, jump # 1st loop handles groups of 4 limbs in a software pipeline .align 4 .Loop: cmpult $5,$21,$25 # compute cy from last add ldq $0,0($18) or $8,$25,$25 # combine cy from the two adds ldq $1,8($18) addq $2,$25,$28 # cy add ldq $4,0($17) subq $6,$28,$22 # 3rd main sub ldq $5,8($17) cmpult $28,$25,$8 # compute cy from last add cmpult $6,$22,$25 # compute cy from last add stq $20,0($16) or $8,$25,$25 # combine cy from the two adds stq $21,8($16) addq $3,$25,$28 # cy add subq $7,$28,$23 # 4th main sub cmpult $28,$25,$8 # compute cy from last add cmpult $7,$23,$25 # compute cy from last add addq $17,32,$17 # update s1_ptr or $8,$25,$25 # combine cy from the two adds addq $16,32,$16 # update res_ptr addq $0,$25,$28 # cy add ldq $2,16($18) subq $4,$28,$20 # 1st main sub ldq $3,24($18) cmpult $28,$25,$8 # compute cy from last add ldq $6,-16($17) cmpult $4,$20,$25 # compute cy from last add ldq $7,-8($17) or $8,$25,$25 # combine cy from the two adds subq $19,4,$19 # decr loop cnt stq $22,-16($16) addq $1,$25,$28 # cy add stq $23,-8($16) subq $5,$28,$21 # 2nd main sub addq $18,32,$18 # update s2_ptr cmpult $28,$25,$8 # compute cy from last add bge $19,.Loop # Finish software pipeline for 1st loop .Lend1: cmpult $5,$21,$25 # compute cy from last add or $8,$25,$25 # combine cy from the two adds addq $2,$25,$28 # cy add subq $6,$28,$22 # 3rd main sub cmpult $28,$25,$8 # compute cy from last add cmpult $6,$22,$25 # compute cy from last add stq $20,0($16) or $8,$25,$25 # combine cy from the two adds stq $21,8($16) addq $3,$25,$28 # cy add subq $7,$28,$23 # 4th main sub cmpult $28,$25,$8 # compute cy from last add cmpult $7,$23,$25 # compute cy from last add or $8,$25,$25 # combine cy from the two adds addq $16,32,$16 # update res_ptr stq $22,-16($16) stq $23,-8($16) .Lend2: addq $19,4,$19 # restore loop cnt beq $19,.Lret # Start software pipeline for 2nd loop ldq $0,0($18) ldq $4,0($17) subq $19,1,$19 beq $19,.Lend0 # 2nd loop handles remaining 1-3 limbs .align 4 .Loop0: addq $0,$25,$28 # cy add ldq $0,8($18) subq $4,$28,$20 # main sub ldq $1,8($17) addq $18,8,$18 cmpult $28,$25,$8 # compute cy from last add addq $17,8,$17 stq $20,0($16) cmpult $4,$20,$25 # compute cy from last add subq $19,1,$19 # decr loop cnt or $8,$25,$25 # combine cy from the two adds addq $16,8,$16 or $1,$31,$4 bne $19,.Loop0 .Lend0: addq $0,$25,$28 # cy add subq $4,$28,$20 # main sub cmpult $28,$25,$8 # compute cy from last add cmpult $4,$20,$25 # compute cy from last add stq $20,0($16) or $8,$25,$25 # combine cy from the two adds .Lret: or $25,$31,$0 # return cy ret $31,($26),1 .end __mpn_sub_n