arch/sparc/lib/memmove.S

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /* memmove.S: Simple memmove implementation.
   3  *
   4  * Copyright (C) 1997, 2004 David S. Miller (davem@redhat.com)
   5  * Copyright (C) 1996, 1997, 1998, 1999 Jakub Jelinek (jj@ultra.linux.cz)
   6  */
   7
   8 #include <linux/linkage.h>
   9 #include <asm/export.h>
  10
  11         .text
  12 ENTRY(memmove) /* o0=dst o1=src o2=len */
  13         brz,pn          %o2, 99f
  14          mov            %o0, %g1
  15
  16         cmp             %o0, %o1
  17         bleu,pt         %xcc, 2f
  18          add            %o1, %o2, %g7
  19         cmp             %g7, %o0
  20         bleu,pt         %xcc, memcpy
  21          add            %o0, %o2, %o5
  22         sub             %g7, 1, %o1
  23
  24         sub             %o5, 1, %o0
  25 1:      ldub            [%o1], %g7
  26         subcc           %o2, 1, %o2
  27         sub             %o1, 1, %o1
  28         stb             %g7, [%o0]
  29         bne,pt          %icc, 1b
  30          sub            %o0, 1, %o0
  31 99:
  32         retl
  33          mov            %g1, %o0
  34
  35         /* We can't just call memcpy for these memmove cases.  On some
  36          * chips the memcpy uses cache initializing stores and when dst
  37          * and src are close enough, those can clobber the source data
  38          * before we've loaded it in.
  39          */
  40 2:      or              %o0, %o1, %g7
  41         or              %o2, %g7, %g7
  42         andcc           %g7, 0x7, %g0
  43         bne,pn          %xcc, 4f
  44          nop
  45
  46 3:      ldx             [%o1], %g7
  47         add             %o1, 8, %o1
  48         subcc           %o2, 8, %o2
  49         add             %o0, 8, %o0
  50         bne,pt          %icc, 3b
  51          stx            %g7, [%o0 - 0x8]
  52         ba,a,pt         %xcc, 99b
  53
  54 4:      ldub            [%o1], %g7
  55         add             %o1, 1, %o1
  56         subcc           %o2, 1, %o2
  57         add             %o0, 1, %o0
  58         bne,pt          %icc, 4b
  59          stb            %g7, [%o0 - 0x1]
  60         ba,a,pt         %xcc, 99b
  61 ENDPROC(memmove)
  62 EXPORT_SYMBOL(memmove)