arch/sh/lib/memmove.S

   1 /* $Id: memmove.S,v 1.2 2001/07/27 11:51:09 gniibe Exp $
   2  *
   3  * "memmove" implementation of SuperH
   4  *
   5  * Copyright (C) 1999  Niibe Yutaka
   6  *
   7  */
   8
   9 /*
  10  * void *memmove(void *dst, const void *src, size_t n);
  11  * The memory areas may overlap.
  12  */
  13
  14 #include <linux/linkage.h>
  15 ENTRY(memmove)
  16         ! if dest > src, call memcpy (it copies in decreasing order)
  17         cmp/hi  r5,r4
  18         bf      1f
  19         mov.l   2f,r0
  20         jmp     @r0
  21          nop
  22         .balign 4
  23 2:      .long   memcpy
  24 1:
  25         sub     r5,r4           ! From here, r4 has the distance to r0
  26         tst     r6,r6
  27         bt/s    9f              ! if n=0, do nothing
  28          mov    r5,r0
  29         add     r6,r5
  30         mov     #12,r1
  31         cmp/gt  r6,r1
  32         bt/s    8f              ! if it's too small, copy a byte at once
  33          add    #-1,r4
  34         add     #1,r4
  35         !
  36         !                [ ...  ] DST             [ ...  ] SRC
  37         !                [ ...  ]                 [ ...  ]
  38         !                  :                        :
  39         !      r0+r4-->  [ ...  ]       r0    --> [ ...  ]
  40         !                  :                        :
  41         !                [ ...  ]                 [ ...  ]
  42         !                               r5    -->
  43         !
  44         mov     r4,r1
  45         mov     #3,r2
  46         and     r2,r1
  47         shll2   r1
  48         mov     r0,r3           ! Save the value on R0 to R3
  49         mova    jmptable,r0
  50         add     r1,r0
  51         mov.l   @r0,r1
  52         jmp     @r1
  53          mov    r3,r0           ! and back to R0
  54         .balign 4
  55 jmptable:
  56         .long   case0
  57         .long   case1
  58         .long   case2
  59         .long   case3
  60
  61         ! copy a byte at once
  62 8:      mov.b   @r0+,r1
  63         cmp/hs  r5,r0
  64         bf/s    8b                      ! while (r0<r5)
  65          mov.b  r1,@(r0,r4)
  66         add     #1,r4
  67 9:
  68         add     r4,r0
  69         rts
  70          sub    r6,r0
  71
  72 case_none:
  73         bra     8b
  74          add    #-1,r4
  75
  76 case0:
  77         !
  78         !       GHIJ KLMN OPQR -->  GHIJ KLMN OPQR
  79         !
  80         ! First, align to long word boundary
  81         mov     r0,r3
  82         and     r2,r3
  83         tst     r3,r3
  84         bt/s    2f
  85          add    #-1,r4
  86         mov     #4,r2
  87         sub     r3,r2
  88 1:      dt      r2
  89         mov.b   @r0+,r1
  90         bf/s    1b
  91          mov.b  r1,@(r0,r4)
  92         !
  93 2:      ! Second, copy a long word at once
  94         add     #-3,r4
  95         add     #-3,r5
  96 3:      mov.l   @r0+,r1
  97         cmp/hs  r5,r0
  98         bf/s    3b
  99          mov.l  r1,@(r0,r4)
 100         add     #3,r5
 101         !
 102         ! Third, copy a byte at once, if necessary
 103         cmp/eq  r5,r0
 104         bt/s    9b
 105          add    #4,r4
 106         bra     8b
 107          add    #-1,r4
 108
 109 case3:
 110         !
 111         !       GHIJ KLMN OPQR -->  ...G HIJK LMNO PQR.
 112         !
 113         ! First, align to long word boundary
 114         mov     r0,r3
 115         and     r2,r3
 116         tst     r3,r3
 117         bt/s    2f
 118          add    #-1,r4
 119         mov     #4,r2
 120         sub     r3,r2
 121 1:      dt      r2
 122         mov.b   @r0+,r1
 123         bf/s    1b
 124          mov.b  r1,@(r0,r4)
 125         !
 126 2:      ! Second, read a long word and write a long word at once
 127         add     #-2,r4
 128         mov.l   @(r0,r4),r1
 129         add     #-7,r5
 130         add     #-4,r4
 131         !
 132 #ifdef __LITTLE_ENDIAN__
 133         shll8   r1
 134 3:      mov     r1,r3           ! JIHG
 135         shlr8   r3              ! xJIH
 136         mov.l   @r0+,r1         ! NMLK
 137         mov     r1,r2
 138         shll16  r2
 139         shll8   r2              ! Kxxx
 140         or      r2,r3           ! KJIH
 141         cmp/hs  r5,r0
 142         bf/s    3b
 143          mov.l  r3,@(r0,r4)
 144 #else
 145         shlr8   r1
 146 3:      mov     r1,r3           ! GHIJ
 147         shll8   r3              ! HIJx
 148         mov.l   @r0+,r1         ! KLMN
 149         mov     r1,r2
 150         shlr16  r2
 151         shlr8   r2              ! xxxK
 152         or      r2,r3           ! HIJK
 153         cmp/hs  r5,r0
 154         bf/s    3b
 155          mov.l  r3,@(r0,r4)
 156 #endif
 157         add     #7,r5
 158         !
 159         ! Third, copy a byte at once, if necessary
 160         cmp/eq  r5,r0
 161         bt/s    9b
 162          add    #7,r4
 163         add     #-3,r0
 164         bra     8b
 165          add    #-1,r4
 166
 167 case2:
 168         !
 169         !       GHIJ KLMN OPQR -->  ..GH IJKL MNOP QR..
 170         !
 171         ! First, align to word boundary
 172         tst     #1,r0
 173         bt/s    2f
 174          add    #-1,r4
 175         mov.b   @r0+,r1
 176         mov.b   r1,@(r0,r4)
 177         !
 178 2:      ! Second, read a word and write a word at once
 179         add     #-1,r4
 180         add     #-1,r5
 181         !
 182 3:      mov.w   @r0+,r1
 183         cmp/hs  r5,r0
 184         bf/s    3b
 185          mov.w  r1,@(r0,r4)
 186         add     #1,r5
 187         !
 188         ! Third, copy a byte at once, if necessary
 189         cmp/eq  r5,r0
 190         bt/s    9b
 191          add    #2,r4
 192         mov.b   @r0,r1
 193         mov.b   r1,@(r0,r4)
 194         bra     9b
 195          add    #1,r0
 196
 197 case1:
 198         !
 199         !       GHIJ KLMN OPQR -->  .GHI JKLM NOPQ R...
 200         !
 201         ! First, align to long word boundary
 202         mov     r0,r3
 203         and     r2,r3
 204         tst     r3,r3
 205         bt/s    2f
 206          add    #-1,r4
 207         mov     #4,r2
 208         sub     r3,r2
 209 1:      dt      r2
 210         mov.b   @r0+,r1
 211         bf/s    1b
 212          mov.b  r1,@(r0,r4)
 213         !
 214 2:      ! Second, read a long word and write a long word at once
 215         mov.l   @(r0,r4),r1
 216         add     #-7,r5
 217         add     #-4,r4
 218         !
 219 #ifdef __LITTLE_ENDIAN__
 220         shll16  r1
 221         shll8   r1
 222 3:      mov     r1,r3           ! JIHG
 223         shlr16  r3
 224         shlr8   r3              ! xxxJ
 225         mov.l   @r0+,r1         ! NMLK
 226         mov     r1,r2
 227         shll8   r2              ! MLKx
 228         or      r2,r3           ! MLKJ
 229         cmp/hs  r5,r0
 230         bf/s    3b
 231          mov.l  r3,@(r0,r4)
 232 #else
 233         shlr16  r1
 234         shlr8   r1
 235 3:      mov     r1,r3           ! GHIJ
 236         shll16  r3
 237         shll8   r3              ! Jxxx
 238         mov.l   @r0+,r1         ! KLMN
 239         mov     r1,r2
 240         shlr8   r2              ! xKLM
 241         or      r2,r3           ! JKLM
 242         cmp/hs  r5,r0
 243         bf/s    3b              ! while(r0<r5)
 244          mov.l  r3,@(r0,r4)
 245 #endif
 246         add     #7,r5
 247         !
 248         ! Third, copy a byte at once, if necessary
 249         cmp/eq  r5,r0
 250         bt/s    9b
 251          add    #5,r4
 252         add     #-3,r0
 253         bra     8b
 254          add    #-1,r4