root/arch/sparc/lib/memscan_32.S

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * memscan.S: Optimized memscan for the Sparc.
   4  *
   5  * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
   6  */
   7 
   8 #include <asm/export.h>
   9 
  10 /* In essence, this is just a fancy strlen. */
  11 
  12 #define LO_MAGIC 0x01010101
  13 #define HI_MAGIC 0x80808080
  14 
  15         .text
  16         .align  4
  17         .globl  __memscan_zero, __memscan_generic
  18         .globl  memscan
  19 EXPORT_SYMBOL(__memscan_zero)
  20 EXPORT_SYMBOL(__memscan_generic)
  21 __memscan_zero:
  22         /* %o0 = addr, %o1 = size */
  23         cmp     %o1, 0
  24         bne,a   1f
  25          andcc  %o0, 3, %g0
  26 
  27         retl
  28          nop
  29 
  30 1:
  31         be      mzero_scan_word
  32          sethi  %hi(HI_MAGIC), %g2
  33 
  34         ldsb    [%o0], %g3
  35 mzero_still_not_word_aligned:
  36         cmp     %g3, 0
  37         bne     1f
  38          add    %o0, 1, %o0
  39 
  40         retl
  41          sub    %o0, 1, %o0
  42 
  43 1:
  44         subcc   %o1, 1, %o1
  45         bne,a   1f
  46          andcc  %o0, 3, %g0
  47 
  48         retl
  49          nop
  50 
  51 1:
  52         bne,a   mzero_still_not_word_aligned
  53          ldsb   [%o0], %g3
  54 
  55         sethi   %hi(HI_MAGIC), %g2
  56 mzero_scan_word:
  57         or      %g2, %lo(HI_MAGIC), %o3
  58         sethi   %hi(LO_MAGIC), %g3
  59         or      %g3, %lo(LO_MAGIC), %o2
  60 mzero_next_word:
  61         ld      [%o0], %g2
  62 mzero_next_word_preloaded:
  63         sub     %g2, %o2, %g2
  64 mzero_next_word_preloaded_next:
  65         andcc   %g2, %o3, %g0
  66         bne     mzero_byte_zero
  67          add    %o0, 4, %o0
  68 
  69 mzero_check_out_of_fuel:
  70         subcc   %o1, 4, %o1
  71         bg,a    1f
  72          ld     [%o0], %g2
  73 
  74         retl
  75          nop
  76 
  77 1:
  78         b       mzero_next_word_preloaded_next
  79          sub    %g2, %o2, %g2
  80 
  81         /* Check every byte. */
  82 mzero_byte_zero:
  83         ldsb    [%o0 - 4], %g2
  84         cmp     %g2, 0
  85         bne     mzero_byte_one
  86          sub    %o0, 4, %g3
  87 
  88         retl
  89          mov    %g3, %o0
  90 
  91 mzero_byte_one:
  92         ldsb    [%o0 - 3], %g2
  93         cmp     %g2, 0
  94         bne,a   mzero_byte_two_and_three
  95          ldsb   [%o0 - 2], %g2
  96 
  97         retl
  98          sub    %o0, 3, %o0
  99 
 100 mzero_byte_two_and_three:
 101         cmp     %g2, 0
 102         bne,a   1f
 103          ldsb   [%o0 - 1], %g2
 104 
 105         retl
 106          sub    %o0, 2, %o0
 107 
 108 1:
 109         cmp     %g2, 0
 110         bne,a   mzero_next_word_preloaded
 111          ld     [%o0], %g2
 112 
 113         retl
 114          sub    %o0, 1, %o0
 115 
 116 mzero_found_it:
 117         retl
 118          sub    %o0, 2, %o0
 119 
 120 memscan:
 121 __memscan_generic:
 122         /* %o0 = addr, %o1 = c, %o2 = size */
 123         cmp     %o2, 0
 124         bne,a   0f
 125          ldub   [%o0], %g2
 126 
 127         b,a     2f
 128 1:
 129         ldub    [%o0], %g2
 130 0:
 131         cmp     %g2, %o1
 132         be      2f
 133          addcc  %o2, -1, %o2
 134         bne     1b
 135          add    %o0, 1, %o0
 136 2:
 137         retl
 138          nop