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ARCv2: lib: introduce memcpy optimized for unaligned access

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Optimise code to use efficient unaligned memory access which is
available on ARCv2. This allows us to really simplify memcpy code
and speed up the code one and a half times (in case of unaligned
source or destination).

Don't wire it up yet !

Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
This commit is contained in:
Eugeniy Paltsev 2019-01-30 19:32:43 +03:00 committed by Vineet Gupta
parent 5d4ab8d096
commit 4d1e7918aa
1 changed files with 47 additions and 0 deletions
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arch/arc/lib/memcpy-archs-unaligned.S Normal file
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/* SPDX-License-Identifier: GPL-2.0+ */
/*
* ARCv2 memcpy implementation optimized for unaligned memory access using.
*
* Copyright (C) 2019 Synopsys
* Author: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
*/
#include <linux/linkage.h>
#ifdef CONFIG_ARC_HAS_LL64
# define LOADX(DST,RX) ldd.ab DST, [RX, 8]
# define STOREX(SRC,RX) std.ab SRC, [RX, 8]
# define ZOLSHFT 5
# define ZOLAND 0x1F
#else
# define LOADX(DST,RX) ld.ab DST, [RX, 4]
# define STOREX(SRC,RX) st.ab SRC, [RX, 4]
# define ZOLSHFT 4
# define ZOLAND 0xF
#endif
ENTRY_CFI(memcpy)
mov r3, r0 ; don;t clobber ret val
lsr.f lp_count, r2, ZOLSHFT
lpnz @.Lcopy32_64bytes
;; LOOP START
LOADX (r6, r1)
LOADX (r8, r1)
LOADX (r10, r1)
LOADX (r4, r1)
STOREX (r6, r3)
STOREX (r8, r3)
STOREX (r10, r3)
STOREX (r4, r3)
.Lcopy32_64bytes:
and.f lp_count, r2, ZOLAND ;Last remaining 31 bytes
lpnz @.Lcopyremainingbytes
;; LOOP START
ldb.ab r5, [r1, 1]
stb.ab r5, [r3, 1]
.Lcopyremainingbytes:
j [blink]
END_CFI(memcpy)