newlib-cygwin/newlib/libc/machine/arm/strcmp.S

/*
 * Copyright (c) 2012-2014 ARM Ltd
 * 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. The name of the company may not be used to endorse or promote
 *    products derived from this software without specific prior written
 *    permission.
 *
 * THIS SOFTWARE IS PROVIDED BY ARM LTD ``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 ARM LTD 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.
 */

/* Wrapper for the various implementations of strcmp.  */

#include "arm_asm.h"

#ifdef __ARM_BIG_ENDIAN
#define S2LO lsl
#define S2LOEQ lsleq
#define S2HI lsr
#define MSB 0x000000ff
#define LSB 0xff000000
#define BYTE0_OFFSET 24
#define BYTE1_OFFSET 16
#define BYTE2_OFFSET 8
#define BYTE3_OFFSET 0
#else /* not  __ARM_BIG_ENDIAN */
#define S2LO lsr
#define S2LOEQ lsreq
#define S2HI lsl
#define BYTE0_OFFSET 0
#define BYTE1_OFFSET 8
#define BYTE2_OFFSET 16
#define BYTE3_OFFSET 24
#define MSB 0xff000000
#define LSB 0x000000ff
#endif /* not  __ARM_BIG_ENDIAN */

	.macro def_fn f p2align=0
	.text
	.p2align \p2align
	.global \f
	.type \f, %function
\f:
	.endm

#if defined (__OPTIMIZE_SIZE__) || defined (PREFER_SIZE_OVER_SPEED) \
	|| (__ARM_ARCH == 6 && __ARM_ARCH_PROFILE == 'M')

# if defined (__thumb__) && !defined (__thumb2__)
/* Thumb1 only variant.  If size is preferred, use strcmp-armv4t.S.
   If speed is preferred, the strcmp function in ../../string/strcmp.c
   will be used.  */

#  if defined (__OPTIMIZE_SIZE__) || defined (PREFER_SIZE_OVER_SPEED)
#   include "strcmp-armv4t.S"
#  else
    /* Leave this field blank.  So the strcmp() is not defined, and this will
       automatically pull in the default C definition of strcmp() from
       ../../string/strcmp.c.  No need to include this file explicitely.
       The lib_a-strcmp.o will not be generated, so it won't replace the
       default lib_a-strcmp.o which is generated by ../../string/strcmp.c.
       See the commands in configure.in and Makefile.am for more details.

       However, if we need to rewrite this function to be more efficient,
       we can add the corresponding assembly code into this field and
       change the commands in configure.in and Makefile.am to allow the
       corresponding lib_a-strcmp.o to be generated.
    */
#  endif

# else
#  include "strcmp-arm-tiny.S"
# endif

#elif __ARM_ARCH >= 7

# ifdef __ARM_FEATURE_SIMD32
#  include "strcmp-armv7.S"
# else
#  include "strcmp-armv7m.S"
# endif

#elif __ARM_ARCH >= 6

# include "strcmp-armv6.S"

#else

# include "strcmp-armv4.S"

#endif