arch/powerpc/lib/string.S

   1 /*
   2  * String handling functions for PowerPC.
   3  *
   4  * Copyright (C) 1996 Paul Mackerras.
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  */
  11 #include <linux/config.h>
  12 #include <asm/processor.h>
  13 #include <asm/errno.h>
  14 #include <asm/ppc_asm.h>
  15
  16         .section __ex_table,"a"
  17 #ifdef CONFIG_PPC64
  18         .align  3
  19 #define EXTBL   .llong
  20 #else
  21         .align  2
  22 #define EXTBL   .long
  23 #endif
  24         .text
  25
  26 _GLOBAL(strcpy)
  27         addi    r5,r3,-1
  28         addi    r4,r4,-1
  29 1:      lbzu    r0,1(r4)
  30         cmpwi   0,r0,0
  31         stbu    r0,1(r5)
  32         bne     1b
  33         blr
  34
  35 /* This clears out any unused part of the destination buffer,
  36    just as the libc version does.  -- paulus */
  37 _GLOBAL(strncpy)
  38         cmpwi   0,r5,0
  39         beqlr
  40         mtctr   r5
  41         addi    r6,r3,-1
  42         addi    r4,r4,-1
  43 1:      lbzu    r0,1(r4)
  44         cmpwi   0,r0,0
  45         stbu    r0,1(r6)
  46         bdnzf   2,1b            /* dec ctr, branch if ctr != 0 && !cr0.eq */
  47         bnelr                   /* if we didn't hit a null char, we're done */
  48         mfctr   r5
  49         cmpwi   0,r5,0          /* any space left in destination buffer? */
  50         beqlr                   /* we know r0 == 0 here */
  51 2:      stbu    r0,1(r6)        /* clear it out if so */
  52         bdnz    2b
  53         blr
  54
  55 _GLOBAL(strcat)
  56         addi    r5,r3,-1
  57         addi    r4,r4,-1
  58 1:      lbzu    r0,1(r5)
  59         cmpwi   0,r0,0
  60         bne     1b
  61         addi    r5,r5,-1
  62 1:      lbzu    r0,1(r4)
  63         cmpwi   0,r0,0
  64         stbu    r0,1(r5)
  65         bne     1b
  66         blr
  67
  68 _GLOBAL(strcmp)
  69         addi    r5,r3,-1
  70         addi    r4,r4,-1
  71 1:      lbzu    r3,1(r5)
  72         cmpwi   1,r3,0
  73         lbzu    r0,1(r4)
  74         subf.   r3,r0,r3
  75         beqlr   1
  76         beq     1b
  77         blr
  78
  79 _GLOBAL(strlen)
  80         addi    r4,r3,-1
  81 1:      lbzu    r0,1(r4)
  82         cmpwi   0,r0,0
  83         bne     1b
  84         subf    r3,r3,r4
  85         blr
  86
  87 _GLOBAL(memcmp)
  88         cmpwi   0,r5,0
  89         ble-    2f
  90         mtctr   r5
  91         addi    r6,r3,-1
  92         addi    r4,r4,-1
  93 1:      lbzu    r3,1(r6)
  94         lbzu    r0,1(r4)
  95         subf.   r3,r0,r3
  96         bdnzt   2,1b
  97         blr
  98 2:      li      r3,0
  99         blr
 100
 101 _GLOBAL(memchr)
 102         cmpwi   0,r5,0
 103         ble-    2f
 104         mtctr   r5
 105         addi    r3,r3,-1
 106 1:      lbzu    r0,1(r3)
 107         cmpw    0,r0,r4
 108         bdnzf   2,1b
 109         beqlr
 110 2:      li      r3,0
 111         blr
 112
 113 _GLOBAL(__clear_user)
 114         addi    r6,r3,-4
 115         li      r3,0
 116         li      r5,0
 117         cmplwi  0,r4,4
 118         blt     7f
 119         /* clear a single word */
 120 11:     stwu    r5,4(r6)
 121         beqlr
 122         /* clear word sized chunks */
 123         andi.   r0,r6,3
 124         add     r4,r0,r4
 125         subf    r6,r0,r6
 126         srwi    r0,r4,2
 127         andi.   r4,r4,3
 128         mtctr   r0
 129         bdz     7f
 130 1:      stwu    r5,4(r6)
 131         bdnz    1b
 132         /* clear byte sized chunks */
 133 7:      cmpwi   0,r4,0
 134         beqlr
 135         mtctr   r4
 136         addi    r6,r6,3
 137 8:      stbu    r5,1(r6)
 138         bdnz    8b
 139         blr
 140 90:     mr      r3,r4
 141         blr
 142 91:     mfctr   r3
 143         slwi    r3,r3,2
 144         add     r3,r3,r4
 145         blr
 146 92:     mfctr   r3
 147         blr
 148
 149         .section __ex_table,"a"
 150         EXTBL   11b,90b
 151         EXTBL   1b,91b
 152         EXTBL   8b,92b
 153         .text
 154
 155 _GLOBAL(__strncpy_from_user)
 156         addi    r6,r3,-1
 157         addi    r4,r4,-1
 158         cmpwi   0,r5,0
 159         beq     2f
 160         mtctr   r5
 161 1:      lbzu    r0,1(r4)
 162         cmpwi   0,r0,0
 163         stbu    r0,1(r6)
 164         bdnzf   2,1b            /* dec ctr, branch if ctr != 0 && !cr0.eq */
 165         beq     3f
 166 2:      addi    r6,r6,1
 167 3:      subf    r3,r3,r6
 168         blr
 169 99:     li      r3,-EFAULT
 170         blr
 171
 172         .section __ex_table,"a"
 173         EXTBL   1b,99b
 174         .text
 175
 176 /* r3 = str, r4 = len (> 0), r5 = top (highest addr) */
 177 _GLOBAL(__strnlen_user)
 178         addi    r7,r3,-1
 179         subf    r6,r7,r5        /* top+1 - str */
 180         cmplw   0,r4,r6
 181         bge     0f
 182         mr      r6,r4
 183 0:      mtctr   r6              /* ctr = min(len, top - str) */
 184 1:      lbzu    r0,1(r7)        /* get next byte */
 185         cmpwi   0,r0,0
 186         bdnzf   2,1b            /* loop if --ctr != 0 && byte != 0 */
 187         addi    r7,r7,1
 188         subf    r3,r3,r7        /* number of bytes we have looked at */
 189         beqlr                   /* return if we found a 0 byte */
 190         cmpw    0,r3,r4         /* did we look at all len bytes? */
 191         blt     99f             /* if not, must have hit top */
 192         addi    r3,r4,1         /* return len + 1 to indicate no null found */
 193         blr
 194 99:     li      r3,0            /* bad address, return 0 */
 195         blr
 196
 197         .section __ex_table,"a"
 198         EXTBL   1b,99b