mirror of
https://github.com/autc04/Retro68.git
synced 2024-11-30 19:53:46 +00:00
97 lines
3.4 KiB
ArmAsm
97 lines
3.4 KiB
ArmAsm
/*
|
|
Copyright (c) 2013 Andes Technology Corporation.
|
|
All rights reserved.
|
|
|
|
Redistribution and use in source and binary forms, with or without
|
|
modification, are permitted provided that the following conditions are met:
|
|
|
|
Redistributions of source code must retain the above copyright
|
|
notice, this list of conditions and the following disclaimer.
|
|
|
|
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.
|
|
|
|
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 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 RED HAT INCORPORATED 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.
|
|
|
|
|
|
Function:
|
|
strcmp - compare two strings.
|
|
Syntax:
|
|
int strcmp(const char *s1, const char *s2);
|
|
Description:
|
|
This function compares the two strings s1 and s2. It returns an
|
|
integer less than, equal to, or greater than zero if s1 is found,
|
|
respectively, to be less than, to match, or be greater than s2.
|
|
Return value:
|
|
strcmp returns an integer less than, equal to, or greater than
|
|
zero if s1 (or the first n bytes thereof) is found, respectively,
|
|
to be less than, to match, or be greater than s2.
|
|
*/
|
|
.text
|
|
.align 2
|
|
.globl strcmp
|
|
.type strcmp, @function
|
|
strcmp:
|
|
/* If s1 or s2 are unaligned, then compare bytes. */
|
|
or $r5, $r1, $r0
|
|
andi $r5, $r5, #3
|
|
bnez $r5, .Lbyte_mode
|
|
|
|
/* If s1 and s2 are word-aligned, compare them a word at a time. */
|
|
lwi $r5, [$r0+(0)]
|
|
lwi $r3, [$r1+(0)]
|
|
bne $r5, $r3, .Lbyte_mode /* A difference was detected, so
|
|
search bytewise. */
|
|
|
|
/* It's more efficient to set bit mask outside the word_mode loop. */
|
|
sethi $r4, hi20(0xFEFEFEFF) /* Set $r4 as -0x01010101. */
|
|
ori $r4, $r4, lo12(0xFEFEFEFF)
|
|
sethi $r2, hi20(0x80808080)
|
|
ori $r2, $r2, lo12(0x80808080)
|
|
b .Ldetect_null
|
|
|
|
.align 2
|
|
.Lword_mode:
|
|
lmw.aim $r5, [$r0], $r5
|
|
lmw.aim $r3, [$r1], $r3
|
|
bne $r5, $r3, .Lbyte_mode
|
|
|
|
.Ldetect_null:
|
|
/* #define DETECTNULL(X) (((X) - 0x01010101) & ~(X) & 0x80808080)
|
|
DETECTNULL returns nonzero if (long)X contains a NULL byte. */
|
|
nor $r3, $r5, $r5 /* r3 = ~(X) */
|
|
add $r5, $r5, $r4 /* r2 = ((X) - 0x01010101) */
|
|
and $r5, $r5, $r3 /* r2 = ~(X) & ((X) - 0x01010101) */
|
|
and $r5, $r5, $r2 /* r2= r2 & 0x80808080 */
|
|
beqz $r5, .Lword_mode /* No NULL byte, compare next word. */
|
|
|
|
/* To get here, *a1 == *a2, thus if we find a null in *a1,
|
|
then the strings must be equal, so return zero. */
|
|
movi $r0, #0
|
|
ret
|
|
|
|
.Lbyte_mode:
|
|
/* Byte-mode compare. */
|
|
lbi.bi $r5, [$r0], #1
|
|
lbi.bi $r3, [$r1], #1
|
|
bne $r5, $r3, 1f /* Mismatch, done. */
|
|
bnez $r5, .Lbyte_mode
|
|
1:
|
|
sub $r0, $r5, $r3
|
|
ret
|
|
.size strcmp, .-strcmp
|