strcpy-700.S
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/*
* Copyright (C) 2004, 2007-2010, 2011-2014 Synopsys, Inc. All rights reserved.
*
* SPDX-License-Identifier: GPL-2.0+
*/
/*
* 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 it is not likely to be taken often, and it would also be likely
* to cost an unaligned mispredict at the next call.
*/
.global strcpy
.align 4
strcpy:
or %r2, %r0, %r1
bmsk_s %r2, %r2, 1
brne.d %r2, 0, charloop
mov_s %r10, %r0
ld_s %r3, [%r1, 0]
mov %r8, 0x01010101
bbit0.d %r1, 2, loop_start
ror %r12, %r8
sub %r2, %r3, %r8
bic_s %r2, %r2, %r3
tst_s %r2,%r12
bne r3z
mov_s %r4,%r3
.balign 4
loop:
ld.a %r3, [%r1, 4]
st.ab %r4, [%r10, 4]
loop_start:
ld.a %r4, [%r1, 4]
sub %r2, %r3, %r8
bic_s %r2, %r2, %r3
tst_s %r2, %r12
bne_s r3z
st.ab %r3, [%r10, 4]
sub %r2, %r4, %r8
bic %r2, %r2, %r4
tst %r2, %r12
beq loop
mov_s %r3, %r4
#ifdef __LITTLE_ENDIAN__
r3z: bmsk.f %r1, %r3, 7
lsr_s %r3, %r3, 8
#else /* __BIG_ENDIAN__ */
r3z: lsr.f %r1, %r3, 24
asl_s %r3, %r3, 8
#endif /* _ENDIAN__ */
bne.d r3z
stb.ab %r1, [%r10, 1]
j_s [%blink]
.balign 4
charloop:
ldb.ab %r3, [%r1, 1]
brne.d %r3, 0, charloop
stb.ab %r3, [%r10, 1]
j [%blink]