arm/string.s

   1
   2 .global memcpy
   3 memcpy:
   4         mov     r12, r0
   5 .loop:
   6         subs    r2, r2, #1
   7         bmi     .ret
   8         ldrb    r3, [r1], #1
   9         strb    r3, [r0], #1
  10         b       .loop
  11 .ret:
  12         mov     r0, r12
  13         mov     pc, lr
  14
  15 .global memset
  16 memset:
  17         mov     r12, r0
  18 .loop:
  19         subs    r2, r2, #1
  20         bmi     .ret
  21         strb    r1, [r0], #1
  22         b       .loop
  23 .ret:
  24         mov     r0, r12
  25         mov     pc, lr
  26
  27 .global memmove
  28 memmove:
  29         mov     r12, r0
  30         cmp     r0, r1
  31         ble     .fw
  32         add     r3, r1, r2
  33         cmp     r0, r3
  34         bgt     .fw
  35
  36         @ copying the memory in reverse order
  37         add     r0, r0, r2
  38         add     r1, r1, r2
  39 .bw:
  40         subs    r2, r2, #1
  41         bmi     .ret
  42         ldrb    r3, [r1, #-1]!
  43         strb    r3, [r0, #-1]!
  44         b       .bw
  45 .fw:
  46         subs    r2, r2, #1
  47         bmi     .ret
  48         ldrb    r3, [r1], #1
  49         strb    r3, [r0], #1
  50         b       .fw
  51 .ret:
  52         mov     r0, r12
  53         mov     pc, lr
  54
  55 .global memchr
  56 memchr:
  57         subs    r2, r2, #1
  58         bmi     .failed
  59         ldrb    r3, [r0], #1
  60         cmp     r3, r1
  61         bne     memchr
  62         sub     r0, r0, #1
  63         b       .ret
  64 .failed:
  65         mov     r0, #0
  66 .ret:
  67         mov     pc, lr
  68
  69 .global memrchr
  70 memrchr:
  71         mov     r12, #0
  72 .loop:
  73         subs    r2, r2, #1
  74         bmi     .ret
  75         ldrb    r3, [r0], #1
  76         cmp     r3, r1
  77         subeq   r12, r0, #1
  78         b       .loop
  79 .ret:
  80         mov     r0, r12
  81         mov     pc, lr
  82
  83 .global memcmp
  84 memcmp:
  85         subs    r2, r2, #1
  86         bmi     .match
  87         ldrb    r3, [r0], #1
  88         ldrb    r12, [r1], #1
  89         subs    r3, r3, r12
  90         movne   r0, r3
  91         bne     .ret
  92         b       memcmp
  93 .match:
  94         mov     r0, #0
  95 .ret:
  96         mov     pc, lr
  97
  98 .global strlen
  99 strlen:
 100         mov     r2, r0
 101 .loop:
 102         ldrb    r1, [r0], #1
 103         tst     r1, r1
 104         bne     .loop
 105         sub     r0, r0, r2
 106         sub     r0, r0, #1
 107         mov     pc, lr
 108
 109 .global strchr
 110 strchr:
 111         ldrb    r2, [r0], #1
 112         cmp     r1, r2
 113         subeq   r0, r0, #1
 114         beq     .ret
 115         tst     r2, r2
 116         bne     strchr
 117         mov     r0, #0
 118 .ret:
 119         mov     pc, lr
 120
 121 .global strrchr
 122 strrchr:
 123         mov     r3, #0
 124 .loop:
 125         ldrb    r2, [r0], #1
 126         cmp     r1, r2
 127         subeq   r3, r0, #1
 128         tst     r2, r2
 129         bne     .loop
 130 .ret:
 131         mov     r0, r3
 132         mov     pc, lr
 133
 134 .global strcmp
 135 strcmp:
 136         ldrb    r2, [r0], #1
 137         ldrb    r3, [r1], #1
 138         cmp     r2, #1
 139         cmpcs   r2, r3
 140         beq     strcmp
 141         sub     r0, r2, r3
 142         mov     pc, lr
 143
 144 .global strcpy
 145 strcpy:
 146         mov     r3, r0
 147 .loop:
 148         ldrb    r2, [r1], #1
 149         strb    r2, [r0], #1
 150         tst     r2, r2
 151         bne     .loop
 152         mov     r0, r3
 153 .ret:
 154         mov     pc, lr
 155
 156 .global strncmp
 157 strncmp:
 158         mov     r12, r2
 159 .loop:
 160         subs    r12, r12, #1
 161         movmi   r0, #0
 162         bmi     .ret
 163         ldrb    r2, [r0], #1
 164         ldrb    r3, [r1], #1
 165         cmp     r2, #1
 166         cmpcs   r2, r3
 167         beq     .loop
 168         sub     r0, r2, r3
 169 .ret:
 170         mov     pc, lr