/* Optimized strcmp implementation for PowerPC476.

   Copyright (C) 2010-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with the GNU C Library.  If not, see

   <http://www.gnu.org/licenses/>.  */

#include <sysdep.h>

/* strcmp

       Register Use

       r0:temp return equality

       r3:source1 address, return equality

       r4:source2 address

       Implementation description

       Check 2 words from src1 and src2. If unequal jump to end and

       return src1 > src2 or src1 < src2.

       If null check bytes before null and then jump to end and

       return src1 > src2, src1 < src2 or src1 = src2.

       If src1 = src2 and no null, repeat. */

EALIGN (strcmp,5,0)

       neg     r7,r3

       clrlwi  r7,r7,20

       neg     r8,r4

       clrlwi  r8,r8,20

       srwi.   r7,r7,5

       beq     L(byte_loop)

       srwi.   r8,r8,5

       beq     L(byte_loop)

       cmplw   r7,r8

       mtctr   r7

       ble     L(big_loop)

       mtctr   r8

L(big_loop):

       lwz     r5,0(r3)

       lwz     r6,4(r3)

       lwz     r8,0(r4)

       lwz     r9,4(r4)

       dlmzb.  r12,r5,r6

       bne     L(end_check)

       cmplw   r5,r8

       bne     L(st1)

       cmplw   r6,r9

       bne     L(st1)

       lwz     r5,8(r3)

       lwz     r6,12(r3)

       lwz     r8,8(r4)

       lwz     r9,12(r4)

       dlmzb.  r12,r5,r6

       bne     L(end_check)

       cmplw   r5,r8

       bne     L(st1)

       cmplw   r6,r9

       bne     L(st1)

       lwz     r5,16(r3)

       lwz     r6,20(r3)

       lwz     r8,16(r4)

       lwz     r9,20(r4)

       dlmzb.  r12,r5,r6

       bne     L(end_check)

       cmplw   r5,r8

       bne     L(st1)

       cmplw   r6,r9

       bne     L(st1)

       lwz     r5,24(r3)

       lwz     r6,28(r3)

       addi    r3,r3,0x20

       lwz     r8,24(r4)

       lwz     r9,28(r4)

       addi    r4,r4,0x20

       dlmzb.  r12,r5,r6

       bne     L(end_check)

       cmplw   r5,r8

       bne     L(st1)

       cmplw   r6,r9

       bne     L(st1)

       bdnz    L(big_loop)

       b       L(byte_loop)

L(end_check):

       subfic  r12,r12,4

       blt     L(end_check2)

       rlwinm  r12,r12,3,0,31

       srw     r5,r5,r12

       srw     r8,r8,r12

       cmplw   r5,r8

       bne     L(st1)

       b       L(end_strcmp)

L(end_check2):

       addi    r12,r12,4

       cmplw   r5,r8

       rlwinm  r12,r12,3,0,31

       bne     L(st1)

       srw     r6,r6,r12

       srw     r9,r9,r12

       cmplw   r6,r9

       bne     L(st1)

L(end_strcmp):

       addi    r3,r0,0

       blr

L(st1):

       mfcr    r3

       blr

L(byte_loop):

       lbz     r5,0(r3)

       addi    r3,r3,1

       lbz     r6,0(r4)

       addi    r4,r4,1

       cmplw   r5,r6

       bne     L(st1)

       cmpwi   r5,0

       beq     L(end_strcmp)

       b       L(byte_loop)

END (strcmp)

libc_hidden_builtin_def (strcmp)