arch/arm/lib/memmove.S

   1 /*
   2  *  linux/arch/arm/lib/memmove.S
   3  *
   4  *  Author:     Nicolas Pitre
   5  *  Created:    Sep 28, 2005
   6  *  Copyright:  (C) MontaVista Software Inc.
   7  *
   8  *  This program is free software; you can redistribute it and/or modify
   9  *  it under the terms of the GNU General Public License version 2 as
  10  *  published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/linkage.h>
  14 #include <asm/assembler.h>
  15
  16                 .text
  17
  18 /*
  19  * Prototype: void *memmove(void *dest, const void *src, size_t n);
  20  *
  21  * Note:
  22  *
  23  * If the memory regions don't overlap, we simply branch to memcpy which is
  24  * normally a bit faster. Otherwise the copy is done going downwards.  This
  25  * is a transposition of the code from copy_template.S but with the copy
  26  * occurring in the opposite direction.
  27  */
  28
  29 ENTRY(memmove)
  30
  31                 subs    ip, r0, r1
  32                 cmphi   r2, ip
  33                 bls     memcpy
  34
  35                 stmfd   sp!, {r0, r4, lr}
  36                 add     r1, r1, r2
  37                 add     r0, r0, r2
  38                 subs    r2, r2, #4
  39                 blt     8f
  40                 ands    ip, r0, #3
  41         PLD(    pld     [r1, #-4]               )
  42                 bne     9f
  43                 ands    ip, r1, #3
  44                 bne     10f
  45
  46 1:              subs    r2, r2, #(28)
  47                 stmfd   sp!, {r5 - r8}
  48                 blt     5f
  49
  50         CALGN(  ands    ip, r0, #31             )
  51         CALGN(  sbcnes  r4, ip, r2              )  @ C is always set here
  52         CALGN(  bcs     2f                      )
  53         CALGN(  adr     r4, 6f                  )
  54         CALGN(  subs    r2, r2, ip              )  @ C is set here
  55         CALGN(  rsb     ip, ip, #32             )
  56         CALGN(  add     pc, r4, ip              )
  57
  58         PLD(    pld     [r1, #-4]               )
  59 2:      PLD(    subs    r2, r2, #96             )
  60         PLD(    pld     [r1, #-32]              )
  61         PLD(    blt     4f                      )
  62         PLD(    pld     [r1, #-64]              )
  63         PLD(    pld     [r1, #-96]              )
  64
  65 3:      PLD(    pld     [r1, #-128]             )
  66 4:              ldmdb   r1!, {r3, r4, r5, r6, r7, r8, ip, lr}
  67                 subs    r2, r2, #32
  68                 stmdb   r0!, {r3, r4, r5, r6, r7, r8, ip, lr}
  69                 bge     3b
  70         PLD(    cmn     r2, #96                 )
  71         PLD(    bge     4b                      )
  72
  73 5:              ands    ip, r2, #28
  74                 rsb     ip, ip, #32
  75                 addne   pc, pc, ip              @ C is always clear here
  76                 b       7f
  77 6:              W(nop)
  78                 W(ldr)  r3, [r1, #-4]!
  79                 W(ldr)  r4, [r1, #-4]!
  80                 W(ldr)  r5, [r1, #-4]!
  81                 W(ldr)  r6, [r1, #-4]!
  82                 W(ldr)  r7, [r1, #-4]!
  83                 W(ldr)  r8, [r1, #-4]!
  84                 W(ldr)  lr, [r1, #-4]!
  85
  86                 add     pc, pc, ip
  87                 nop
  88                 W(nop)
  89                 W(str)  r3, [r0, #-4]!
  90                 W(str)  r4, [r0, #-4]!
  91                 W(str)  r5, [r0, #-4]!
  92                 W(str)  r6, [r0, #-4]!
  93                 W(str)  r7, [r0, #-4]!
  94                 W(str)  r8, [r0, #-4]!
  95                 W(str)  lr, [r0, #-4]!
  96
  97         CALGN(  bcs     2b                      )
  98
  99 7:              ldmfd   sp!, {r5 - r8}
 100
 101 8:              movs    r2, r2, lsl #31
 102                 ldrneb  r3, [r1, #-1]!
 103                 ldrcsb  r4, [r1, #-1]!
 104                 ldrcsb  ip, [r1, #-1]
 105                 strneb  r3, [r0, #-1]!
 106                 strcsb  r4, [r0, #-1]!
 107                 strcsb  ip, [r0, #-1]
 108                 ldmfd   sp!, {r0, r4, pc}
 109
 110 9:              cmp     ip, #2
 111                 ldrgtb  r3, [r1, #-1]!
 112                 ldrgeb  r4, [r1, #-1]!
 113                 ldrb    lr, [r1, #-1]!
 114                 strgtb  r3, [r0, #-1]!
 115                 strgeb  r4, [r0, #-1]!
 116                 subs    r2, r2, ip
 117                 strb    lr, [r0, #-1]!
 118                 blt     8b
 119                 ands    ip, r1, #3
 120                 beq     1b
 121
 122 10:             bic     r1, r1, #3
 123                 cmp     ip, #2
 124                 ldr     r3, [r1, #0]
 125                 beq     17f
 126                 blt     18f
 127
 128
 129                 .macro  backward_copy_shift push pull
 130
 131                 subs    r2, r2, #28
 132                 blt     14f
 133
 134         CALGN(  ands    ip, r0, #31             )
 135         CALGN(  sbcnes  r4, ip, r2              )  @ C is always set here
 136         CALGN(  subcc   r2, r2, ip              )
 137         CALGN(  bcc     15f                     )
 138
 139 11:             stmfd   sp!, {r5 - r9}
 140
 141         PLD(    pld     [r1, #-4]               )
 142         PLD(    subs    r2, r2, #96             )
 143         PLD(    pld     [r1, #-32]              )
 144         PLD(    blt     13f                     )
 145         PLD(    pld     [r1, #-64]              )
 146         PLD(    pld     [r1, #-96]              )
 147
 148 12:     PLD(    pld     [r1, #-128]             )
 149 13:             ldmdb   r1!, {r7, r8, r9, ip}
 150                 mov     lr, r3, push #\push
 151                 subs    r2, r2, #32
 152                 ldmdb   r1!, {r3, r4, r5, r6}
 153                 orr     lr, lr, ip, pull #\pull
 154                 mov     ip, ip, push #\push
 155                 orr     ip, ip, r9, pull #\pull
 156                 mov     r9, r9, push #\push
 157                 orr     r9, r9, r8, pull #\pull
 158                 mov     r8, r8, push #\push
 159                 orr     r8, r8, r7, pull #\pull
 160                 mov     r7, r7, push #\push
 161                 orr     r7, r7, r6, pull #\pull
 162                 mov     r6, r6, push #\push
 163                 orr     r6, r6, r5, pull #\pull
 164                 mov     r5, r5, push #\push
 165                 orr     r5, r5, r4, pull #\pull
 166                 mov     r4, r4, push #\push
 167                 orr     r4, r4, r3, pull #\pull
 168                 stmdb   r0!, {r4 - r9, ip, lr}
 169                 bge     12b
 170         PLD(    cmn     r2, #96                 )
 171         PLD(    bge     13b                     )
 172
 173                 ldmfd   sp!, {r5 - r9}
 174
 175 14:             ands    ip, r2, #28
 176                 beq     16f
 177
 178 15:             mov     lr, r3, push #\push
 179                 ldr     r3, [r1, #-4]!
 180                 subs    ip, ip, #4
 181                 orr     lr, lr, r3, pull #\pull
 182                 str     lr, [r0, #-4]!
 183                 bgt     15b
 184         CALGN(  cmp     r2, #0                  )
 185         CALGN(  bge     11b                     )
 186
 187 16:             add     r1, r1, #(\pull / 8)
 188                 b       8b
 189
 190                 .endm
 191
 192
 193                 backward_copy_shift     push=8  pull=24
 194
 195 17:             backward_copy_shift     push=16 pull=16
 196
 197 18:             backward_copy_shift     push=24 pull=8
 198
 199 ENDPROC(memmove)