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sh: Optimised memset for SH4

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Optimised version of memset for the SH4 which uses movca.l.

Signed-off-by: Stuart Menefy <stuart.menefy@st.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
This commit is contained in:
Stuart Menefy 2009-10-27 15:14:06 +00:00 committed by Paul Mundt
parent a0458b07c1
commit dfc349402d
2 changed files with 112 additions and 2 deletions
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7
arch/sh/lib/Makefile
View file

@ -2,7 +2,7 @@
# Makefile for SuperH-specific library files..
#
lib-y = delay.o memset.o memmove.o memchr.o \
lib-y = delay.o memmove.o memchr.o \
checksum.o strlen.o div64.o div64-generic.o
# Extracted from libgcc
@ -23,8 +23,11 @@ obj-y += io.o
memcpy-y := memcpy.o
memcpy-$(CONFIG_CPU_SH4) := memcpy-sh4.o
memset-y := memset.o
memset-$(CONFIG_CPU_SH4) := memset-sh4.o
lib-$(CONFIG_MMU) += copy_page.o __clear_user.o
lib-$(CONFIG_MCOUNT) += mcount.o
lib-y += $(memcpy-y) $(udivsi3-y)
lib-y += $(memcpy-y) $(memset-y) $(udivsi3-y)
EXTRA_CFLAGS += -Werror

107
arch/sh/lib/memset-sh4.S Normal file
View file

@ -0,0 +1,107 @@
/*
* "memset" implementation for SH4
*
* Copyright (C) 1999 Niibe Yutaka
* Copyright (c) 2009 STMicroelectronics Limited
* Author: Stuart Menefy <stuart.menefy:st.com>
*/
/*
* void *memset(void *s, int c, size_t n);
*/
#include <linux/linkage.h>
ENTRY(memset)
mov #12,r0
add r6,r4
cmp/gt r6,r0
bt/s 40f ! if it's too small, set a byte at once
mov r4,r0
and #3,r0
cmp/eq #0,r0
bt/s 2f ! It's aligned
sub r0,r6
1:
dt r0
bf/s 1b
mov.b r5,@-r4
2: ! make VVVV
extu.b r5,r5
swap.b r5,r0 ! V0
or r0,r5 ! VV
swap.w r5,r0 ! VV00
or r0,r5 ! VVVV
! Check if enough bytes need to be copied to be worth the big loop
mov #0x40, r0 ! (MT)
cmp/gt r6,r0 ! (MT) 64 > len => slow loop
bt/s 22f
mov r6,r0
! align the dst to the cache block size if necessary
mov r4, r3
mov #~(0x1f), r1
and r3, r1
cmp/eq r3, r1
bt/s 11f ! dst is already aligned
sub r1, r3 ! r3-r1 -> r3
shlr2 r3 ! number of loops
10: mov.l r5,@-r4
dt r3
bf/s 10b
add #-4, r6
11: ! dst is 32byte aligned
mov r6,r2
mov #-5,r0
shld r0,r2 ! number of loops
add #-32, r4
mov r5, r0
12:
movca.l r0,@r4
mov.l r5,@(4, r4)
mov.l r5,@(8, r4)
mov.l r5,@(12,r4)
mov.l r5,@(16,r4)
mov.l r5,@(20,r4)
add #-0x20, r6
mov.l r5,@(24,r4)
dt r2
mov.l r5,@(28,r4)
bf/s 12b
add #-32, r4
add #32, r4
mov #8, r0
cmp/ge r0, r6
bf 40f
mov r6,r0
22:
shlr2 r0
shlr r0 ! r0 = r6 >> 3
3:
dt r0
mov.l r5,@-r4 ! set 8-byte at once
bf/s 3b
mov.l r5,@-r4
!
mov #7,r0
and r0,r6
! fill bytes (length may be zero)
40: tst r6,r6
bt 5f
4:
dt r6
bf/s 4b
mov.b r5,@-r4
5:
rts
mov r4,r0