| dnl Alpha EV5 mpn_sub_n -- Subtract two limb vectors of the same length > 0 |
| dnl and store difference in a third limb vector. |
| |
| dnl Copyright 1995, 1999, 2000, 2005 Free Software Foundation, Inc. |
| |
| dnl This file is part of the GNU MP Library. |
| |
| dnl The GNU MP Library is free software; you can redistribute it and/or modify |
| dnl it under the terms of the GNU Lesser General Public License as published |
| dnl by the Free Software Foundation; either version 3 of the License, or (at |
| dnl your option) any later version. |
| |
| dnl The GNU MP Library is distributed in the hope that it will be useful, but |
| dnl WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY |
| dnl or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public |
| dnl License for more details. |
| |
| dnl You should have received a copy of the GNU Lesser General Public License |
| dnl along with the GNU MP Library. If not, see http://www.gnu.org/licenses/. |
| |
| include(`../config.m4') |
| |
| C cycles/limb |
| C EV4: ? |
| C EV5: 4.75 |
| C EV6: 3 |
| |
| dnl INPUT PARAMETERS |
| dnl res_ptr r16 |
| dnl s1_ptr r17 |
| dnl s2_ptr r18 |
| dnl size r19 |
| |
| ASM_START() |
| PROLOGUE(mpn_sub_n) |
| bis r31,r31,r25 C clear cy |
| subq r19,4,r19 C decr loop cnt |
| blt r19,$Lend2 C if less than 4 limbs, goto 2nd loop |
| C Start software pipeline for 1st loop |
| ldq r0,0(r18) |
| ldq r4,0(r17) |
| ldq r1,8(r18) |
| ldq r5,8(r17) |
| addq r17,32,r17 C update s1_ptr |
| ldq r2,16(r18) |
| subq r4,r0,r20 C 1st main subtract |
| ldq r3,24(r18) |
| subq r19,4,r19 C decr loop cnt |
| ldq r6,-16(r17) |
| cmpult r4,r0,r25 C compute cy from last subtract |
| ldq r7,-8(r17) |
| subq r5,r1,r28 C 2nd main subtract |
| addq r18,32,r18 C update s2_ptr |
| subq r28,r25,r21 C 2nd carry subtract |
| cmpult r5,r1,r8 C compute cy from last subtract |
| blt r19,$Lend1 C if less than 4 limbs remain, jump |
| C 1st loop handles groups of 4 limbs in a software pipeline |
| ALIGN(16) |
| $Loop: cmpult r28,r25,r25 C compute cy from last subtract |
| ldq r0,0(r18) |
| bis r8,r25,r25 C combine cy from the two subtracts |
| ldq r1,8(r18) |
| subq r6,r2,r28 C 3rd main subtract |
| ldq r4,0(r17) |
| subq r28,r25,r22 C 3rd carry subtract |
| ldq r5,8(r17) |
| cmpult r6,r2,r8 C compute cy from last subtract |
| cmpult r28,r25,r25 C compute cy from last subtract |
| stq r20,0(r16) |
| bis r8,r25,r25 C combine cy from the two subtracts |
| stq r21,8(r16) |
| subq r7,r3,r28 C 4th main subtract |
| subq r28,r25,r23 C 4th carry subtract |
| cmpult r7,r3,r8 C compute cy from last subtract |
| cmpult r28,r25,r25 C compute cy from last subtract |
| addq r17,32,r17 C update s1_ptr |
| bis r8,r25,r25 C combine cy from the two subtracts |
| addq r16,32,r16 C update res_ptr |
| subq r4,r0,r28 C 1st main subtract |
| ldq r2,16(r18) |
| subq r28,r25,r20 C 1st carry subtract |
| ldq r3,24(r18) |
| cmpult r4,r0,r8 C compute cy from last subtract |
| ldq r6,-16(r17) |
| cmpult r28,r25,r25 C compute cy from last subtract |
| ldq r7,-8(r17) |
| bis r8,r25,r25 C combine cy from the two subtracts |
| subq r19,4,r19 C decr loop cnt |
| stq r22,-16(r16) |
| subq r5,r1,r28 C 2nd main subtract |
| stq r23,-8(r16) |
| subq r28,r25,r21 C 2nd carry subtract |
| addq r18,32,r18 C update s2_ptr |
| cmpult r5,r1,r8 C compute cy from last subtract |
| bge r19,$Loop |
| C Finish software pipeline for 1st loop |
| $Lend1: cmpult r28,r25,r25 C compute cy from last subtract |
| bis r8,r25,r25 C combine cy from the two subtracts |
| subq r6,r2,r28 C cy add |
| subq r28,r25,r22 C 3rd main subtract |
| cmpult r6,r2,r8 C compute cy from last subtract |
| cmpult r28,r25,r25 C compute cy from last subtract |
| stq r20,0(r16) |
| bis r8,r25,r25 C combine cy from the two subtracts |
| stq r21,8(r16) |
| subq r7,r3,r28 C cy add |
| subq r28,r25,r23 C 4th main subtract |
| cmpult r7,r3,r8 C compute cy from last subtract |
| cmpult r28,r25,r25 C compute cy from last subtract |
| bis r8,r25,r25 C combine cy from the two subtracts |
| addq r16,32,r16 C update res_ptr |
| stq r22,-16(r16) |
| stq r23,-8(r16) |
| $Lend2: addq r19,4,r19 C restore loop cnt |
| beq r19,$Lret |
| C Start software pipeline for 2nd loop |
| ldq r0,0(r18) |
| ldq r4,0(r17) |
| subq r19,1,r19 |
| beq r19,$Lend0 |
| C 2nd loop handles remaining 1-3 limbs |
| ALIGN(16) |
| $Loop0: subq r4,r0,r28 C main subtract |
| cmpult r4,r0,r8 C compute cy from last subtract |
| ldq r0,8(r18) |
| ldq r4,8(r17) |
| subq r28,r25,r20 C carry subtract |
| addq r18,8,r18 |
| addq r17,8,r17 |
| stq r20,0(r16) |
| cmpult r28,r25,r25 C compute cy from last subtract |
| subq r19,1,r19 C decr loop cnt |
| bis r8,r25,r25 C combine cy from the two subtracts |
| addq r16,8,r16 |
| bne r19,$Loop0 |
| $Lend0: subq r4,r0,r28 C main subtract |
| subq r28,r25,r20 C carry subtract |
| cmpult r4,r0,r8 C compute cy from last subtract |
| cmpult r28,r25,r25 C compute cy from last subtract |
| stq r20,0(r16) |
| bis r8,r25,r25 C combine cy from the two subtracts |
| |
| $Lret: bis r25,r31,r0 C return cy |
| ret r31,(r26),1 |
| EPILOGUE(mpn_sub_n) |
| ASM_END() |
