arch/sparc/lib/memmove.S

   1 /* memmove.S: Simple memmove implementation.
   2  *
   3  * Copyright (C) 1997, 2004 David S. Miller (davem@redhat.com)
   4  * Copyright (C) 1996, 1997, 1998, 1999 Jakub Jelinek (jj@ultra.linux.cz)
   5  */
   6
   7 #include <linux/linkage.h>
   8
   9         .text
  10 ENTRY(memmove) /* o0=dst o1=src o2=len */
  11         brz,pn          %o2, 99f
  12          mov            %o0, %g1
  13
  14         cmp             %o0, %o1
  15         bleu,pt         %xcc, 2f
  16          add            %o1, %o2, %g7
  17         cmp             %g7, %o0
  18         bleu,pt         %xcc, memcpy
  19          add            %o0, %o2, %o5
  20         sub             %g7, 1, %o1
  21
  22         sub             %o5, 1, %o0
  23 1:      ldub            [%o1], %g7
  24         subcc           %o2, 1, %o2
  25         sub             %o1, 1, %o1
  26         stb             %g7, [%o0]
  27         bne,pt          %icc, 1b
  28          sub            %o0, 1, %o0
  29 99:
  30         retl
  31          mov            %g1, %o0
  32
  33         /* We can't just call memcpy for these memmove cases.  On some
  34          * chips the memcpy uses cache initializing stores and when dst
  35          * and src are close enough, those can clobber the source data
  36          * before we've loaded it in.
  37          */
  38 2:      or              %o0, %o1, %g7
  39         or              %o2, %g7, %g7
  40         andcc           %g7, 0x7, %g0
  41         bne,pn          %xcc, 4f
  42          nop
  43
  44 3:      ldx             [%o1], %g7
  45         add             %o1, 8, %o1
  46         subcc           %o2, 8, %o2
  47         add             %o0, 8, %o0
  48         bne,pt          %icc, 3b
  49          stx            %g7, [%o0 - 0x8]
  50         ba,a,pt         %xcc, 99b
  51
  52 4:      ldub            [%o1], %g7
  53         add             %o1, 1, %o1
  54         subcc           %o2, 1, %o2
  55         add             %o0, 1, %o0
  56         bne,pt          %icc, 4b
  57          stb            %g7, [%o0 - 0x1]
  58         ba,a,pt         %xcc, 99b
  59 ENDPROC(memmove)