| # Alpha 21064 __mpn_lshift -- |
| |
| # Copyright (C) 1994-2016 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 <http://www.gnu.org/licenses/>. |
| |
| |
| # INPUT PARAMETERS |
| # res_ptr r16 |
| # s1_ptr r17 |
| # size r18 |
| # cnt r19 |
| |
| # This code runs at 4.8 cycles/limb on the 21064. With infinite unrolling, |
| # it would take 4 cycles/limb. It should be possible to get down to 3 |
| # cycles/limb since both ldq and stq can be paired with the other used |
| # instructions. But there are many restrictions in the 21064 pipeline that |
| # makes it hard, if not impossible, to get down to 3 cycles/limb: |
| |
| # 1. ldq has a 3 cycle delay, srl and sll have a 2 cycle delay. |
| # 2. Only aligned instruction pairs can be paired. |
| # 3. The store buffer or silo might not be able to deal with the bandwidth. |
| |
| .set noreorder |
| .set noat |
| .text |
| .align 3 |
| .globl __mpn_lshift |
| .ent __mpn_lshift |
| __mpn_lshift: |
| .frame $30,0,$26,0 |
| |
| s8addq $18,$17,$17 # make r17 point at end of s1 |
| ldq $4,-8($17) # load first limb |
| subq $17,8,$17 |
| subq $31,$19,$7 |
| s8addq $18,$16,$16 # make r16 point at end of RES |
| subq $18,1,$18 |
| and $18,4-1,$20 # number of limbs in first loop |
| srl $4,$7,$0 # compute function result |
| |
| beq $20,.L0 |
| subq $18,$20,$18 |
| |
| .align 3 |
| .Loop0: |
| ldq $3,-8($17) |
| subq $16,8,$16 |
| subq $17,8,$17 |
| subq $20,1,$20 |
| sll $4,$19,$5 |
| srl $3,$7,$6 |
| bis $3,$3,$4 |
| bis $5,$6,$8 |
| stq $8,0($16) |
| bne $20,.Loop0 |
| |
| .L0: beq $18,.Lend |
| |
| .align 3 |
| .Loop: ldq $3,-8($17) |
| subq $16,32,$16 |
| subq $18,4,$18 |
| sll $4,$19,$5 |
| srl $3,$7,$6 |
| |
| ldq $4,-16($17) |
| sll $3,$19,$1 |
| bis $5,$6,$8 |
| stq $8,24($16) |
| srl $4,$7,$2 |
| |
| ldq $3,-24($17) |
| sll $4,$19,$5 |
| bis $1,$2,$8 |
| stq $8,16($16) |
| srl $3,$7,$6 |
| |
| ldq $4,-32($17) |
| sll $3,$19,$1 |
| bis $5,$6,$8 |
| stq $8,8($16) |
| srl $4,$7,$2 |
| |
| subq $17,32,$17 |
| bis $1,$2,$8 |
| stq $8,0($16) |
| |
| bgt $18,.Loop |
| |
| .Lend: sll $4,$19,$8 |
| stq $8,-8($16) |
| ret $31,($26),1 |
| .end __mpn_lshift |