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/*
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/strncpy.c will be
used. */
#if !defined (__OPTIMIZE_SIZE__) && !defined (PREFER_SIZE_OVER_SPEED)
#include "asm.h"
/* If dst and src are 4 byte aligned, copy 8 bytes at a time.
If the src is 4, but not 8 byte aligned, we first read 4 bytes to get
it 8 byte aligned. Thus, we can do a little read-ahead, without
dereferencing a cache line that we should not touch.
Note that short and long instructions have been scheduled to avoid
branch stalls.
The beq_s to r3z could be made unaligned & long to avoid a stall
there, but the it is not likely to be taken often, and it
would also be likey to cost an unaligned mispredict at the next call. */
#if !defined (__ARC601__) && defined (__Xbarrel_shifter)
#if defined (__ARC700___) || defined (__EM__) || defined (__HS__)
#define BRand(a,b,l) tst a,b ` bne_l l
#else
#define BRand(a,b,l) and a,a,b ` brne_s a,0,l
#endif
ENTRY (strncpy)
cmp_s r2,8
or r12,r0,r1
bmsk.cc.f r12,r12,1
brne.d r12,0,.Lbytewise
mov_s r10,r0
ld_s r3,[r1,0]
mov r8,0x01010101
sub lp_count,r2,1
bbit0.d r1,2,.Loop_start
ror r11,r8
sub r12,r3,r8
bic_l r12,r12,r3
BRand (r12,r11,.Lr3z)
mov_s r4,r3
ld.a r3,[r1,4]
sub lp_count,lp_count,4
st.ab r4,[r10,4]
.balign 4
.Loop_start:
lsr.f lp_count,lp_count,3
lpne .Loop_end
ld.a r4,[r1,4]
sub r12,r3,r8
bic_s r12,r12,r3
BRand (r12,r11,.Lr3z)
st.ab r3,[r10,4]
sub r12,r4,r8
bic r12,r12,r4
BRand (r12,r11,.Lr4z)
ld.a r3,[r1,4]
st.ab r4,[r10,4]
.Loop_end:
bcc_s .Lastword
ld.a r4,[r1,4]
sub r12,r3,r8
bic_s r12,r12,r3
BRand (r12,r11,.Lr3z)
st.ab r3,[r10,4]
mov_s r3,r4
.Lastword:
and.f lp_count,r2,3
mov.eq lp_count,4
lp .Last_byte_end
#ifdef __LITTLE_ENDIAN__
bmsk.f r1,r3,7
lsr.ne r3,r3,8
#else
lsr.f r1,r3,24
asl.ne r3,r3,8
#endif
stb.ab r1,[r10,1]
.Last_byte_end:
j_s [blink]
.balign 4
.Lr4z:
mov_l r3,r4
.Lr3z:
#if defined (__ARC700__) || defined (__EM__) || defined (__HS__)
#ifdef __LITTLE_ENDIAN__
bmsk.f r1,r3,7
lsr_s r3,r3,8
#else
lsr.f r1,r3,24
asl_s r3,r3,8
#endif
bne.d .Lr3z
stb.ab r1,[r10,1]
#else /* ! __ARC700__ */
#ifdef __LITTLE_ENDIAN__
bmsk.f r1,r3,7
.Lr3z_loop:
lsr_s r3,r3,8
stb.ab r1,[r10,1]
bne.d .Lr3z_loop
bmsk.f r1,r3,7
#else
lsr.f r1,r3,24
.Lr3z_loop:
asl_s r3,r3,8
stb.ab r1,[r10,1]
bne.d .Lr3z_loop
lsr.f r1,r3,24
#endif /* ENDIAN */
#endif /* ! __ARC700__ */
.Lzero_rest:
; __strncpy_bzero requires:
; return value in r0
; zeroing length in r2
; zeroing start address in r3
mov_s r3,r10
add_s r2,r2,r0
b.d __strncpy_bzero
sub_s r2,r2,r3
.balign 4
.Lbytewise:
sub.f r2,r2,1
mov_l r3,r0
jcs [blink]
.Lcharloop:
ldb.ab r12,[r1,1]
beq.d .Last_byte
sub.f r2,r2,1
brne.d r12,0,.Lcharloop
stb.ab r12,[r3,1]
b.d __strncpy_bzero
stb.ab r12,[r3,1]
.Last_byte:
j_s.d [blink]
stb_l r12,[r3]
ENDFUNC (strncpy)
#endif /* !__ARC601__ && __Xbarrel_shifter */
#endif /* !__OPTIMIZE_SIZE__ && !PREFER_SIZE_OVER_SPEED */
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