arch/powerpc/lib/string.S

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2 /*
   3  * String handling functions for PowerPC.
   4  *
   5  * Copyright (C) 1996 Paul Mackerras.
   6  */
   7 #include <linux/export.h>
   8 #include <asm/ppc_asm.h>
   9 #include <asm/cache.h>
  10
  11         .text
  12
  13 /* This clears out any unused part of the destination buffer,
  14    just as the libc version does.  -- paulus */
  15 _GLOBAL(strncpy)
  16         PPC_LCMPI 0,r5,0
  17         beqlr
  18         mtctr   r5
  19         addi    r6,r3,-1
  20         addi    r4,r4,-1
  21         .balign IFETCH_ALIGN_BYTES
  22 1:      lbzu    r0,1(r4)
  23         cmpwi   0,r0,0
  24         stbu    r0,1(r6)
  25         bdnzf   2,1b            /* dec ctr, branch if ctr != 0 && !cr0.eq */
  26         bnelr                   /* if we didn't hit a null char, we're done */
  27         mfctr   r5
  28         PPC_LCMPI 0,r5,0        /* any space left in destination buffer? */
  29         beqlr                   /* we know r0 == 0 here */
  30 2:      stbu    r0,1(r6)        /* clear it out if so */
  31         bdnz    2b
  32         blr
  33 EXPORT_SYMBOL(strncpy)
  34
  35 _GLOBAL(strncmp)
  36         PPC_LCMPI 0,r5,0
  37         beq-    2f
  38         mtctr   r5
  39         addi    r5,r3,-1
  40         addi    r4,r4,-1
  41         .balign IFETCH_ALIGN_BYTES
  42 1:      lbzu    r3,1(r5)
  43         cmpwi   1,r3,0
  44         lbzu    r0,1(r4)
  45         subf.   r3,r0,r3
  46         beqlr   1
  47         bdnzt   eq,1b
  48         blr
  49 2:      li      r3,0
  50         blr
  51 EXPORT_SYMBOL(strncmp)
  52
  53 _GLOBAL(memchr)
  54         PPC_LCMPI 0,r5,0
  55         beq-    2f
  56         mtctr   r5
  57         addi    r3,r3,-1
  58         .balign IFETCH_ALIGN_BYTES
  59 1:      lbzu    r0,1(r3)
  60         cmpw    0,r0,r4
  61         bdnzf   2,1b
  62         beqlr
  63 2:      li      r3,0
  64         blr
  65 EXPORT_SYMBOL(memchr)