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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
*
* Copyright (c) 2009 STMicroelectronics Ltd
* Optimised using 64bit data transfer via FPU
* Author: Giuseppe Cavallaro <peppe.cavallaro@st.com>
*
* Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
*/
/*
* void *memset(void *s, int c, size_t n);
*/
#include <sysdep.h>
#ifdef __LITTLE_ENDIAN__
#define MEMSET_USES_FPU
/* Use paired single precision load or store mode for 64-bit tranfering.
* FPSCR.SZ=1,FPSCR.SZ=0 is well defined on both SH4-200 and SH4-300.
* Currenlty it has been only implemented and tested for little endian mode. */
.macro FPU_SET_PAIRED_PREC
sts fpscr, r3
mov #0x10, r0 ! PR=0 SZ=1
shll16 r0
lds r0, fpscr
.endm
.macro RESTORE_FPSCR
lds r3, fpscr
.endm
#endif
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
! Enough bytes need to be copied
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
#ifdef MEMSET_USES_FPU
lds r5, fpul ! (CO)
fsts fpul, fr0 ! Dr0 will be 'VVVVVVVV'
fsts fpul, fr1
FPU_SET_PAIRED_PREC
12:
add #-0x20, r6 !(MT)
fmov dr0, @-r4
fmov dr0, @-r4
fmov dr0, @-r4
dt r2
bf/s 12b !(BR)
fmov dr0, @-r4
RESTORE_FPSCR
#else
12:
mov.l r5,@-r4
mov.l r5,@-r4
mov.l r5,@-r4
mov.l r5,@-r4
mov.l r5,@-r4
mov.l r5,@-r4
add #-0x20, r6
mov.l r5,@-r4
dt r2
bf/s 12b
mov.l r5,@-r4
#endif
tst r6,r6
bt/s 5f
mov #8, r0
cmp/ge r0, r6
bf/s 4f
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
tst r6,r6
bt 5f
! fill bytes
4:
dt r6
bf/s 4b
mov.b r5,@-r4
5:
rts
mov r4,r0
END(memset)
libc_hidden_def (memset)
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