| ;! HP-PA-1.1 __mpn_submul_1 -- Multiply a limb vector with a limb and |
| ;! subtract the result from a second limb vector. |
| |
| ;! Copyright (C) 1992-2014 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 r26 |
| ;! s1_ptr r25 |
| ;! size r24 |
| ;! s2_limb r23 |
| |
| ;! This runs at 12 cycles/limb on a PA7000. With the used instructions, it |
| ;! can not become faster due to data cache contention after a store. On the |
| ;! PA7100 it runs at 11 cycles/limb, and that can not be improved either, |
| ;! since only the xmpyu does not need the integer pipeline, so the only |
| ;! dual-issue we will get are addc+xmpyu. Unrolling could gain a cycle/limb |
| ;! on the PA7100. |
| |
| ;! There are some ideas described in mul_1.s that applies to this code too. |
| |
| ;! It seems possible to make this run as fast as __mpn_addmul_1, if we use |
| ;! sub,>>= %r29,%r20,%r22 |
| ;! addi 1,%r28,%r28 |
| ;! but that requires reworking the hairy software pipeline... |
| |
| .text |
| .export __mpn_submul_1 |
| __mpn_submul_1: |
| .proc |
| .callinfo frame=64,no_calls |
| .entry |
| |
| ldo 64(%r30),%r30 |
| fldws,ma 4(%r25),%fr5 |
| stw %r23,-16(%r30) ;! move s2_limb ... |
| addib,= -1,%r24,L$just_one_limb |
| fldws -16(%r30),%fr4 ;! ... into fr4 |
| add %r0,%r0,%r0 ;! clear carry |
| xmpyu %fr4,%fr5,%fr6 |
| fldws,ma 4(%r25),%fr7 |
| fstds %fr6,-16(%r30) |
| xmpyu %fr4,%fr7,%fr8 |
| ldw -12(%r30),%r20 ;! least significant limb in product |
| ldw -16(%r30),%r28 |
| |
| fstds %fr8,-16(%r30) |
| addib,= -1,%r24,L$end |
| ldw -12(%r30),%r1 |
| |
| ;! Main loop |
| L$loop: |
| ldws 0(%r26),%r29 |
| fldws,ma 4(%r25),%fr5 |
| sub %r29,%r20,%r22 |
| add %r22,%r20,%r0 |
| stws,ma %r22,4(%r26) |
| addc %r28,%r1,%r20 |
| xmpyu %fr4,%fr5,%fr6 |
| ldw -16(%r30),%r28 |
| fstds %fr6,-16(%r30) |
| addc %r0,%r28,%r28 |
| addib,<> -1,%r24,L$loop |
| ldw -12(%r30),%r1 |
| |
| L$end: |
| ldw 0(%r26),%r29 |
| sub %r29,%r20,%r22 |
| add %r22,%r20,%r0 |
| stws,ma %r22,4(%r26) |
| addc %r28,%r1,%r20 |
| ldw -16(%r30),%r28 |
| ldws 0(%r26),%r29 |
| addc %r0,%r28,%r28 |
| sub %r29,%r20,%r22 |
| add %r22,%r20,%r0 |
| stws,ma %r22,4(%r26) |
| addc %r0,%r28,%r28 |
| bv 0(%r2) |
| ldo -64(%r30),%r30 |
| |
| L$just_one_limb: |
| xmpyu %fr4,%fr5,%fr6 |
| ldw 0(%r26),%r29 |
| fstds %fr6,-16(%r30) |
| ldw -12(%r30),%r1 |
| ldw -16(%r30),%r28 |
| sub %r29,%r1,%r22 |
| add %r22,%r1,%r0 |
| stw %r22,0(%r26) |
| addc %r0,%r28,%r28 |
| bv 0(%r2) |
| ldo -64(%r30),%r30 |
| |
| .exit |
| .procend |
