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/*
* Copyright (C) 2013, 2014-2015, 2017 Synopsys, Inc. (www.synopsys.com)
* Copyright (C) 2007 ARC International (UK) LTD
*
* Licensed under the LGPL v2.1 or later, see the file COPYING.LIB in this tarball.
*/
#include <features.h>
#include <sysdep.h>
#if !defined(__ARC700__) && !defined(__ARCHS__)
#error "Neither ARC700 nor ARCHS is defined!"
#endif
ENTRY(strcmp)
#ifdef __ARC700__
/* This is optimized primarily for the ARC700.
It would be possible to speed up the loops by one cycle / word
respective one cycle / byte by forcing double source 1 alignment, unrolling
by a factor of two, and speculatively loading the second word / byte of
source 1; however, that would increase the overhead for loop setup / finish,
and strcmp might often terminate early. */
or r2,r0,r1
bmsk_s r2,r2,1
brne r2,0,.Lcharloop
mov_s r12,0x01010101
ror r5,r12
.Lwordloop:
ld.ab r2,[r0,4]
ld.ab r3,[r1,4]
nop_s
sub r4,r2,r12
bic r4,r4,r2
and r4,r4,r5
brne r4,0,.Lfound0
breq r2,r3,.Lwordloop
#ifdef __LITTLE_ENDIAN__
xor r0,r2,r3 ; mask for difference
sub_s r1,r0,1
bic_s r0,r0,r1 ; mask for least significant difference bit
sub r1,r5,r0
xor r0,r5,r1 ; mask for least significant difference byte
and_s r2,r2,r0
and_s r3,r3,r0
#endif /* LITTLE ENDIAN */
cmp_s r2,r3
mov_s r0,1
j_s.d [blink]
bset.lo r0,r0,31
.balign 4
#ifdef __LITTLE_ENDIAN__
.Lfound0:
xor r0,r2,r3 ; mask for difference
or r0,r0,r4 ; or in zero indicator
sub_s r1,r0,1
bic_s r0,r0,r1 ; mask for least significant difference bit
sub r1,r5,r0
xor r0,r5,r1 ; mask for least significant difference byte
and_s r2,r2,r0
and_s r3,r3,r0
sub.f r0,r2,r3
mov.hi r0,1
j_s.d [blink]
bset.lo r0,r0,31
#else /* BIG ENDIAN */
/* The zero-detection above can mis-detect 0x01 bytes as zeroes
because of carry-propagateion from a lower significant zero byte.
We can compensate for this by checking that bit0 is zero.
This compensation is not necessary in the step where we
get a low estimate for r2, because in any affected bytes
we already have 0x00 or 0x01, which will remain unchanged
when bit 7 is cleared. */
.balign 4
.Lfound0:
lsr r0,r4,8
lsr_s r1,r2
bic_s r2,r2,r0 ; get low estimate for r2 and get ...
bic_s r0,r0,r1 ; <this is the adjusted mask for zeros>
or_s r3,r3,r0 ; ... high estimate r3 so that r2 > r3 will ...
cmp_s r3,r2 ; ... be independent of trailing garbage
or_s r2,r2,r0 ; likewise for r3 > r2
bic_s r3,r3,r0
rlc r0,0 ; r0 := r2 > r3 ? 1 : 0
cmp_s r2,r3
j_s.d [blink]
bset.lo r0,r0,31
#endif /* ENDIAN */
.balign 4
.Lcharloop:
ldb.ab r2,[r0,1]
ldb.ab r3,[r1,1]
nop_s
breq r2,0,.Lcmpend
breq r2,r3,.Lcharloop
.Lcmpend:
j_s.d [blink]
sub r0,r2,r3
#endif /* __ARC700__ */
#ifdef __ARCHS__
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
#endif /* __ARCHS__ */
END(strcmp)
libc_hidden_def(strcmp)
#ifndef __UCLIBC_HAS_LOCALE__
strong_alias(strcmp,strcoll)
libc_hidden_def(strcoll)
#endif
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