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