68 lines
1.5 KiB
ArmAsm
68 lines
1.5 KiB
ArmAsm
/*
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* Copyright (C) 2004, 2007-2010, 2011-2014 Synopsys, Inc. All rights reserved.
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*
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* SPDX-License-Identifier: GPL-2.0+
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*/
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/*
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* If dst and src are 4 byte aligned, copy 8 bytes at a time.
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* If the src is 4, but not 8 byte aligned, we first read 4 bytes to get
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* it 8 byte aligned. Thus, we can do a little read-ahead, without
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* dereferencing a cache line that we should not touch.
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* Note that short and long instructions have been scheduled to avoid
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* branch stalls.
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* The beq_s to r3z could be made unaligned & long to avoid a stall
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* there, but it is not likely to be taken often, and it would also be likely
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* to cost an unaligned mispredict at the next call.
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*/
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.global strcpy
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.align 4
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strcpy:
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or %r2, %r0, %r1
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bmsk_s %r2, %r2, 1
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brne.d %r2, 0, charloop
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mov_s %r10, %r0
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ld_s %r3, [%r1, 0]
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mov %r8, 0x01010101
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bbit0.d %r1, 2, loop_start
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ror %r12, %r8
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sub %r2, %r3, %r8
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bic_s %r2, %r2, %r3
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tst_s %r2,%r12
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bne r3z
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mov_s %r4,%r3
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.balign 4
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loop:
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ld.a %r3, [%r1, 4]
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st.ab %r4, [%r10, 4]
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loop_start:
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ld.a %r4, [%r1, 4]
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sub %r2, %r3, %r8
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bic_s %r2, %r2, %r3
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tst_s %r2, %r12
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bne_s r3z
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st.ab %r3, [%r10, 4]
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sub %r2, %r4, %r8
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bic %r2, %r2, %r4
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tst %r2, %r12
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beq loop
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mov_s %r3, %r4
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#ifdef __LITTLE_ENDIAN__
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r3z: bmsk.f %r1, %r3, 7
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lsr_s %r3, %r3, 8
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#else /* __BIG_ENDIAN__ */
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r3z: lsr.f %r1, %r3, 24
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asl_s %r3, %r3, 8
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#endif /* _ENDIAN__ */
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bne.d r3z
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stb.ab %r1, [%r10, 1]
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j_s [%blink]
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.balign 4
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charloop:
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ldb.ab %r3, [%r1, 1]
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brne.d %r3, 0, charloop
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stb.ab %r3, [%r10, 1]
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j [%blink]
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