arch/sparc/lib/strncpy_from_user.S

   1 /* strncpy_from_user.S: Sparc strncpy from userspace.
   2  *
   3  *  Copyright(C) 1996 David S. Miller
   4  */
   5
   6 #include <asm/ptrace.h>
   7 #include <asm/errno.h>
   8
   9         .text
  10         .align  4
  11
  12         /* Must return:
  13          *
  14          * -EFAULT              for an exception
  15          * count                if we hit the buffer limit
  16          * bytes copied         if we hit a null byte
  17          */
  18
  19         .globl  __strncpy_from_user
  20 __strncpy_from_user:
  21         /* %o0=dest, %o1=src, %o2=count */
  22         mov     %o2, %o3
  23 1:
  24         subcc   %o2, 1, %o2
  25         bneg    2f
  26          nop
  27 10:
  28         ldub    [%o1], %o4
  29         add     %o0, 1, %o0
  30         cmp     %o4, 0
  31         add     %o1, 1, %o1
  32         bne     1b
  33          stb    %o4, [%o0 - 1]
  34 2:
  35         add     %o2, 1, %o0
  36         retl
  37          sub    %o3, %o0, %o0
  38
  39         .section .fixup,#alloc,#execinstr
  40         .align  4
  41 4:
  42         retl
  43          mov    -EFAULT, %o0
  44
  45         .section __ex_table,#alloc
  46         .align  4
  47         .word   10b, 4b