memset.S
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/* $Id: memset.S,v 1.1 2000/04/14 16:49:01 mjd Exp $
*
* "memset" implementation of SuperH
*
* Copyright (C) 1999 Niibe Yutaka
*
*/
/*
* void *memset(void *s, int c, size_t n);
*/
#include <linux/linkage.h>
ENTRY(memset)
tst r6,r6
bt/s 5f ! if n=0, do nothing
add r6,r4
mov #12,r0
cmp/gt r6,r0
bt/s 4f ! 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
!
mov r6,r0
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
tst r6,r6
bt 5f
! fill bytes
4:
dt r6
bf/s 4b
mov.b r5,@-r4
5:
rts
mov r4,r0