arch/powerpc/lib/memcmp_64.S

   1 /*
   2  * Author: Anton Blanchard <anton@au.ibm.com>
   3  * Copyright 2015 IBM Corporation.
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License
   7  * as published by the Free Software Foundation; either version
   8  * 2 of the License, or (at your option) any later version.
   9  */
  10 #include <asm/ppc_asm.h>
  11
  12 #define off8    r6
  13 #define off16   r7
  14 #define off24   r8
  15
  16 #define rA      r9
  17 #define rB      r10
  18 #define rC      r11
  19 #define rD      r27
  20 #define rE      r28
  21 #define rF      r29
  22 #define rG      r30
  23 #define rH      r31
  24
  25 #ifdef __LITTLE_ENDIAN__
  26 #define LD      ldbrx
  27 #else
  28 #define LD      ldx
  29 #endif
  30
  31 _GLOBAL(memcmp)
  32         cmpdi   cr1,r5,0
  33
  34         /* Use the short loop if both strings are not 8B aligned */
  35         or      r6,r3,r4
  36         andi.   r6,r6,7
  37
  38         /* Use the short loop if length is less than 32B */
  39         cmpdi   cr6,r5,31
  40
  41         beq     cr1,.Lzero
  42         bne     .Lshort
  43         bgt     cr6,.Llong
  44
  45 .Lshort:
  46         mtctr   r5
  47
  48 1:      lbz     rA,0(r3)
  49         lbz     rB,0(r4)
  50         subf.   rC,rB,rA
  51         bne     .Lnon_zero
  52         bdz     .Lzero
  53
  54         lbz     rA,1(r3)
  55         lbz     rB,1(r4)
  56         subf.   rC,rB,rA
  57         bne     .Lnon_zero
  58         bdz     .Lzero
  59
  60         lbz     rA,2(r3)
  61         lbz     rB,2(r4)
  62         subf.   rC,rB,rA
  63         bne     .Lnon_zero
  64         bdz     .Lzero
  65
  66         lbz     rA,3(r3)
  67         lbz     rB,3(r4)
  68         subf.   rC,rB,rA
  69         bne     .Lnon_zero
  70
  71         addi    r3,r3,4
  72         addi    r4,r4,4
  73
  74         bdnz    1b
  75
  76 .Lzero:
  77         li      r3,0
  78         blr
  79
  80 .Lnon_zero:
  81         mr      r3,rC
  82         blr
  83
  84 .Llong:
  85         li      off8,8
  86         li      off16,16
  87         li      off24,24
  88
  89         std     r31,-8(r1)
  90         std     r30,-16(r1)
  91         std     r29,-24(r1)
  92         std     r28,-32(r1)
  93         std     r27,-40(r1)
  94
  95         srdi    r0,r5,5
  96         mtctr   r0
  97         andi.   r5,r5,31
  98
  99         LD      rA,0,r3
 100         LD      rB,0,r4
 101
 102         LD      rC,off8,r3
 103         LD      rD,off8,r4
 104
 105         LD      rE,off16,r3
 106         LD      rF,off16,r4
 107
 108         LD      rG,off24,r3
 109         LD      rH,off24,r4
 110         cmpld   cr0,rA,rB
 111
 112         addi    r3,r3,32
 113         addi    r4,r4,32
 114
 115         bdz     .Lfirst32
 116
 117         LD      rA,0,r3
 118         LD      rB,0,r4
 119         cmpld   cr1,rC,rD
 120
 121         LD      rC,off8,r3
 122         LD      rD,off8,r4
 123         cmpld   cr6,rE,rF
 124
 125         LD      rE,off16,r3
 126         LD      rF,off16,r4
 127         cmpld   cr7,rG,rH
 128         bne     cr0,.LcmpAB
 129
 130         LD      rG,off24,r3
 131         LD      rH,off24,r4
 132         cmpld   cr0,rA,rB
 133         bne     cr1,.LcmpCD
 134
 135         addi    r3,r3,32
 136         addi    r4,r4,32
 137
 138         bdz     .Lsecond32
 139
 140         .balign 16
 141
 142 1:      LD      rA,0,r3
 143         LD      rB,0,r4
 144         cmpld   cr1,rC,rD
 145         bne     cr6,.LcmpEF
 146
 147         LD      rC,off8,r3
 148         LD      rD,off8,r4
 149         cmpld   cr6,rE,rF
 150         bne     cr7,.LcmpGH
 151
 152         LD      rE,off16,r3
 153         LD      rF,off16,r4
 154         cmpld   cr7,rG,rH
 155         bne     cr0,.LcmpAB
 156
 157         LD      rG,off24,r3
 158         LD      rH,off24,r4
 159         cmpld   cr0,rA,rB
 160         bne     cr1,.LcmpCD
 161
 162         addi    r3,r3,32
 163         addi    r4,r4,32
 164
 165         bdnz    1b
 166
 167 .Lsecond32:
 168         cmpld   cr1,rC,rD
 169         bne     cr6,.LcmpEF
 170
 171         cmpld   cr6,rE,rF
 172         bne     cr7,.LcmpGH
 173
 174         cmpld   cr7,rG,rH
 175         bne     cr0,.LcmpAB
 176
 177         bne     cr1,.LcmpCD
 178         bne     cr6,.LcmpEF
 179         bne     cr7,.LcmpGH
 180
 181 .Ltail:
 182         ld      r31,-8(r1)
 183         ld      r30,-16(r1)
 184         ld      r29,-24(r1)
 185         ld      r28,-32(r1)
 186         ld      r27,-40(r1)
 187
 188         cmpdi   r5,0
 189         beq     .Lzero
 190         b       .Lshort
 191
 192 .Lfirst32:
 193         cmpld   cr1,rC,rD
 194         cmpld   cr6,rE,rF
 195         cmpld   cr7,rG,rH
 196
 197         bne     cr0,.LcmpAB
 198         bne     cr1,.LcmpCD
 199         bne     cr6,.LcmpEF
 200         bne     cr7,.LcmpGH
 201
 202         b       .Ltail
 203
 204 .LcmpAB:
 205         li      r3,1
 206         bgt     cr0,.Lout
 207         li      r3,-1
 208         b       .Lout
 209
 210 .LcmpCD:
 211         li      r3,1
 212         bgt     cr1,.Lout
 213         li      r3,-1
 214         b       .Lout
 215
 216 .LcmpEF:
 217         li      r3,1
 218         bgt     cr6,.Lout
 219         li      r3,-1
 220         b       .Lout
 221
 222 .LcmpGH:
 223         li      r3,1
 224         bgt     cr7,.Lout
 225         li      r3,-1
 226
 227 .Lout:
 228         ld      r31,-8(r1)
 229         ld      r30,-16(r1)
 230         ld      r29,-24(r1)
 231         ld      r28,-32(r1)
 232         ld      r27,-40(r1)
 233         blr