arch/ppc/boot/common/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 #define r0      0
  12 #define r3      3
  13 #define r4      4
  14 #define r5      5
  15 #define r6      6
  16 #define r7      7
  17 #define r8      8
  18
  19         .globl  strlen
  20 strlen:
  21         addi    r4,r3,-1
  22 1:      lbzu    r0,1(r4)
  23         cmpwi   0,r0,0
  24         bne     1b
  25         subf    r3,r3,r4
  26         blr
  27
  28         .globl  memset
  29 memset:
  30         rlwimi  r4,r4,8,16,23
  31         rlwimi  r4,r4,16,0,15
  32         addi    r6,r3,-4
  33         cmplwi  0,r5,4
  34         blt     7f
  35         stwu    r4,4(r6)
  36         beqlr
  37         andi.   r0,r6,3
  38         add     r5,r0,r5
  39         subf    r6,r0,r6
  40         rlwinm  r0,r5,32-2,2,31
  41         mtctr   r0
  42         bdz     6f
  43 1:      stwu    r4,4(r6)
  44         bdnz    1b
  45 6:      andi.   r5,r5,3
  46 7:      cmpwi   0,r5,0
  47         beqlr
  48         mtctr   r5
  49         addi    r6,r6,3
  50 8:      stbu    r4,1(r6)
  51         bdnz    8b
  52         blr
  53
  54         .globl  memmove
  55 memmove:
  56         cmplw   0,r3,r4
  57         bgt     backwards_memcpy
  58         /* fall through */
  59
  60         .globl  memcpy
  61 memcpy:
  62         rlwinm. r7,r5,32-3,3,31         /* r0 = r5 >> 3 */
  63         addi    r6,r3,-4
  64         addi    r4,r4,-4
  65         beq     2f                      /* if less than 8 bytes to do */
  66         andi.   r0,r6,3                 /* get dest word aligned */
  67         mtctr   r7
  68         bne     5f
  69 1:      lwz     r7,4(r4)
  70         lwzu    r8,8(r4)
  71         stw     r7,4(r6)
  72         stwu    r8,8(r6)
  73         bdnz    1b
  74         andi.   r5,r5,7
  75 2:      cmplwi  0,r5,4
  76         blt     3f
  77         lwzu    r0,4(r4)
  78         addi    r5,r5,-4
  79         stwu    r0,4(r6)
  80 3:      cmpwi   0,r5,0
  81         beqlr
  82         mtctr   r5
  83         addi    r4,r4,3
  84         addi    r6,r6,3
  85 4:      lbzu    r0,1(r4)
  86         stbu    r0,1(r6)
  87         bdnz    4b
  88         blr
  89 5:      subfic  r0,r0,4
  90         mtctr   r0
  91 6:      lbz     r7,4(r4)
  92         addi    r4,r4,1
  93         stb     r7,4(r6)
  94         addi    r6,r6,1
  95         bdnz    6b
  96         subf    r5,r0,r5
  97         rlwinm. r7,r5,32-3,3,31
  98         beq     2b
  99         mtctr   r7
 100         b       1b
 101
 102         .globl  backwards_memcpy
 103 backwards_memcpy:
 104         rlwinm. r7,r5,32-3,3,31         /* r0 = r5 >> 3 */
 105         add     r6,r3,r5
 106         add     r4,r4,r5
 107         beq     2f
 108         andi.   r0,r6,3
 109         mtctr   r7
 110         bne     5f
 111 1:      lwz     r7,-4(r4)
 112         lwzu    r8,-8(r4)
 113         stw     r7,-4(r6)
 114         stwu    r8,-8(r6)
 115         bdnz    1b
 116         andi.   r5,r5,7
 117 2:      cmplwi  0,r5,4
 118         blt     3f
 119         lwzu    r0,-4(r4)
 120         subi    r5,r5,4
 121         stwu    r0,-4(r6)
 122 3:      cmpwi   0,r5,0
 123         beqlr
 124         mtctr   r5
 125 4:      lbzu    r0,-1(r4)
 126         stbu    r0,-1(r6)
 127         bdnz    4b
 128         blr
 129 5:      mtctr   r0
 130 6:      lbzu    r7,-1(r4)
 131         stbu    r7,-1(r6)
 132         bdnz    6b
 133         subf    r5,r0,r5
 134         rlwinm. r7,r5,32-3,3,31
 135         beq     2b
 136         mtctr   r7
 137         b       1b
 138
 139         .globl  memcmp
 140 memcmp:
 141         cmpwi   0,r5,0
 142         blelr
 143         mtctr   r5
 144         addi    r6,r3,-1
 145         addi    r4,r4,-1
 146 1:      lbzu    r3,1(r6)
 147         lbzu    r0,1(r4)
 148         subf.   r3,r0,r3
 149         bdnzt   2,1b
 150         blr