source: trunk/libs/newlib/src/newlib/libc/machine/arc/strcmp-archs.S @ 444

/*
   Copyright (c) 2015, Synopsys, Inc. All rights reserved.

   Redistribution and use in source and binary forms, with or without
   modification, are permitted provided that the following conditions are met:

   1) Redistributions of source code must retain the above copyright notice,
   this list of conditions and the following disclaimer.

   2) Redistributions in binary form must reproduce the above copyright notice,
   this list of conditions and the following disclaimer in the documentation
   and/or other materials provided with the distribution.

   3) Neither the name of the Synopsys, Inc., nor the names of its contributors
   may be used to endorse or promote products derived from this software
   without specific prior written permission.

   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
   AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
   LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
   CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
   SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
   INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
   CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   POSSIBILITY OF SUCH DAMAGE.
*/

/* This implementation is optimized for performance.  For code size a generic
   implementation of this function from newlib/libc/string/strcmp.c will be
   used.  */
#if !defined (__OPTIMIZE_SIZE__) && !defined (PREFER_SIZE_OVER_SPEED)

#include "asm.h"

#ifdef __ARCHS__
ENTRY (strcmp)
        or      r2, r0, r1
        bmsk_s  r2, r2, 1
        brne    r2, 0, @.Lcharloop

; s1 and s2 are word aligned
        ld.ab   r2, [r0, 4]

        mov_s   r12, 0x01010101
        ror     r11, r12
        .align  4
.LwordLoop:
        ld.ab   r3, [r1, 4]
        ; Detect NULL char in str1
        sub     r4, r2, r12
        ld.ab   r5, [r0, 4]
        bic     r4, r4, r2
        and     r4, r4, r11
        brne.d.nt       r4, 0, .LfoundNULL
        ; Check if the read locations are the same
        cmp     r2, r3
        beq.d   .LwordLoop
        mov.eq  r2, r5

        ; A match is found, spot it out
#ifdef __LITTLE_ENDIAN__
        swape   r3, r3
        mov_s   r0, 1
        swape   r2, r2
#else
        mov_s   r0, 1
#endif
        cmp_s   r2, r3
        j_s.d   [blink]
        bset.lo r0, r0, 31

        .align 4
.LfoundNULL:
#ifdef __BIG_ENDIAN__
        swape   r4, r4
        swape   r2, r2
        swape   r3, r3
#endif
        ; Find null byte
        ffs     r0, r4
        bmsk    r2, r2, r0
        bmsk    r3, r3, r0
        swape   r2, r2
        swape   r3, r3
        ; make the return value
        sub.f   r0, r2, r3
        mov.hi  r0, 1
        j_s.d   [blink]
        bset.lo r0, r0, 31

        .align 4
.Lcharloop:
        ldb.ab  r2, [r0, 1]
        ldb.ab  r3, [r1, 1]
        nop
        breq    r2, 0, .Lcmpend
        breq    r2, r3, .Lcharloop

        .align 4
.Lcmpend:
        j_s.d   [blink]
        sub     r0, r2, r3
ENDFUNC (strcmp)
#endif /* __ARCHS__ */

#endif /* !__OPTIMIZE_SIZE__ && !PREFER_SIZE_OVER_SPEED */