sysdeps/powerpc/powerpc32/405/memcmp.S

   1 /* Optimized memcmp implementation for PowerPC476.
   2    Copyright (C) 2010-2019 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library.  If not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <sysdep.h>
  20
  21 /* memcmp
  22
  23        r3:source1 address, return equality
  24        r4:source2 address
  25        r5:byte count
  26
  27        Check 2 words from src1 and src2. If unequal jump to end and
  28        return src1 > src2 or src1 < src2.
  29        If count = zero check bytes before zero counter and then jump to end and
  30        return src1 > src2, src1 < src2 or src1 = src2.
  31        If src1 = src2 and no null, repeat. */
  32
  33 EALIGN (memcmp, 5, 0)
  34        srwi.   r6,r5,5
  35        beq     L(preword2_count_loop)
  36        mtctr   r6
  37        clrlwi  r5,r5,27
  38
  39 L(word8_compare_loop):
  40        lwz     r10,0(r3)
  41        lwz     r6,4(r3)
  42        lwz     r8,0(r4)
  43        lwz     r9,4(r4)
  44        cmplw   cr5,r8,r10
  45        cmplw   cr1,r9,r6
  46        bne     cr5,L(st2)
  47        bne     cr1,L(st1)
  48        lwz     r10,8(r3)
  49        lwz     r6,12(r3)
  50        lwz     r8,8(r4)
  51        lwz     r9,12(r4)
  52        cmplw   cr5,r8,r10
  53        cmplw   cr1,r9,r6
  54        bne     cr5,L(st2)
  55        bne     cr1,L(st1)
  56        lwz     r10,16(r3)
  57        lwz     r6,20(r3)
  58        lwz     r8,16(r4)
  59        lwz     r9,20(r4)
  60        cmplw   cr5,r8,r10
  61        cmplw   cr1,r9,r6
  62        bne     cr5,L(st2)
  63        bne     cr1,L(st1)
  64        lwz     r10,24(r3)
  65        lwz     r6,28(r3)
  66        addi    r3,r3,0x20
  67        lwz     r8,24(r4)
  68        lwz     r9,28(r4)
  69        addi    r4,r4,0x20
  70        cmplw   cr5,r8,r10
  71        cmplw   cr1,r9,r6
  72        bne     cr5,L(st2)
  73        bne     cr1,L(st1)
  74        bdnz    L(word8_compare_loop)
  75
  76 L(preword2_count_loop):
  77        srwi.   r6,r5,3
  78        beq     L(prebyte_count_loop)
  79        mtctr   r6
  80        clrlwi  r5,r5,29
  81
  82 L(word2_count_loop):
  83        lwz     r10,0(r3)
  84        lwz     r6,4(r3)
  85        addi    r3,r3,0x08
  86        lwz     r8,0(r4)
  87        lwz     r9,4(r4)
  88        addi    r4,r4,0x08
  89        cmplw   cr5,r8,r10
  90        cmplw   cr1,r9,r6
  91        bne     cr5,L(st2)
  92        bne     cr1,L(st1)
  93        bdnz    L(word2_count_loop)
  94
  95 L(prebyte_count_loop):
  96        addi    r5,r5,1
  97        mtctr   r5
  98        bdz     L(end_memcmp)
  99
 100 L(byte_count_loop):
 101        lbz     r6,0(r3)
 102        addi    r3,r3,0x01
 103        lbz     r8,0(r4)
 104        addi    r4,r4,0x01
 105        cmplw   cr5,r8,r6
 106        bne     cr5,L(st2)
 107        bdnz    L(byte_count_loop)
 108
 109 L(end_memcmp):
 110        addi    r3,r0,0
 111        blr
 112
 113 L(l_r):
 114        addi    r3,r0,1
 115        blr
 116
 117 L(st1):
 118        blt     cr1,L(l_r)
 119        addi    r3,r0,-1
 120        blr
 121
 122 L(st2):
 123        blt     cr5,L(l_r)
 124        addi    r3,r0,-1
 125        blr
 126 END (memcmp)
 127 libc_hidden_builtin_def (memcmp)
 128 weak_alias (memcmp,bcmp)