kernel-ark/arch/sh/lib/memmove.S

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/* $Id: memmove.S,v 1.2 2001/07/27 11:51:09 gniibe Exp $
*
* "memmove" implementation of SuperH
*
* Copyright (C) 1999 Niibe Yutaka
*
*/
/*
* void *memmove(void *dst, const void *src, size_t n);
* The memory areas may overlap.
*/
#include <linux/linkage.h>
ENTRY(memmove)
! if dest > src, call memcpy (it copies in decreasing order)
cmp/hi r5,r4
bf 1f
mov.l 2f,r0
jmp @r0
nop
.balign 4
2: .long memcpy
1:
sub r5,r4 ! From here, r4 has the distance to r0
tst r6,r6
bt/s 9f ! if n=0, do nothing
mov r5,r0
add r6,r5
mov #12,r1
cmp/gt r6,r1
bt/s 8f ! if it's too small, copy a byte at once
add #-1,r4
add #1,r4
!
! [ ... ] DST [ ... ] SRC
! [ ... ] [ ... ]
! : :
! r0+r4--> [ ... ] r0 --> [ ... ]
! : :
! [ ... ] [ ... ]
! r5 -->
!
mov r4,r1
mov #3,r2
and r2,r1
shll2 r1
mov r0,r3 ! Save the value on R0 to R3
mova jmptable,r0
add r1,r0
mov.l @r0,r1
jmp @r1
mov r3,r0 ! and back to R0
.balign 4
jmptable:
.long case0
.long case1
.long case2
.long case3
! copy a byte at once
8: mov.b @r0+,r1
cmp/hs r5,r0
bf/s 8b ! while (r0<r5)
mov.b r1,@(r0,r4)
add #1,r4
9:
add r4,r0
rts
sub r6,r0
case_none:
bra 8b
add #-1,r4
case0:
!
! GHIJ KLMN OPQR --> GHIJ KLMN OPQR
!
! First, align to long word boundary
mov r0,r3
and r2,r3
tst r3,r3
bt/s 2f
add #-1,r4
mov #4,r2
sub r3,r2
1: dt r2
mov.b @r0+,r1
bf/s 1b
mov.b r1,@(r0,r4)
!
2: ! Second, copy a long word at once
add #-3,r4
add #-3,r5
3: mov.l @r0+,r1
cmp/hs r5,r0
bf/s 3b
mov.l r1,@(r0,r4)
add #3,r5
!
! Third, copy a byte at once, if necessary
cmp/eq r5,r0
bt/s 9b
add #4,r4
bra 8b
add #-1,r4
case3:
!
! GHIJ KLMN OPQR --> ...G HIJK LMNO PQR.
!
! First, align to long word boundary
mov r0,r3
and r2,r3
tst r3,r3
bt/s 2f
add #-1,r4
mov #4,r2
sub r3,r2
1: dt r2
mov.b @r0+,r1
bf/s 1b
mov.b r1,@(r0,r4)
!
2: ! Second, read a long word and write a long word at once
add #-2,r4
mov.l @(r0,r4),r1
add #-7,r5
add #-4,r4
!
#ifdef __LITTLE_ENDIAN__
shll8 r1
3: mov r1,r3 ! JIHG
shlr8 r3 ! xJIH
mov.l @r0+,r1 ! NMLK
mov r1,r2
shll16 r2
shll8 r2 ! Kxxx
or r2,r3 ! KJIH
cmp/hs r5,r0
bf/s 3b
mov.l r3,@(r0,r4)
#else
shlr8 r1
3: mov r1,r3 ! GHIJ
shll8 r3 ! HIJx
mov.l @r0+,r1 ! KLMN
mov r1,r2
shlr16 r2
shlr8 r2 ! xxxK
or r2,r3 ! HIJK
cmp/hs r5,r0
bf/s 3b
mov.l r3,@(r0,r4)
#endif
add #7,r5
!
! Third, copy a byte at once, if necessary
cmp/eq r5,r0
bt/s 9b
add #7,r4
add #-3,r0
bra 8b
add #-1,r4
case2:
!
! GHIJ KLMN OPQR --> ..GH IJKL MNOP QR..
!
! First, align to word boundary
tst #1,r0
bt/s 2f
add #-1,r4
mov.b @r0+,r1
mov.b r1,@(r0,r4)
!
2: ! Second, read a word and write a word at once
add #-1,r4
add #-1,r5
!
3: mov.w @r0+,r1
cmp/hs r5,r0
bf/s 3b
mov.w r1,@(r0,r4)
add #1,r5
!
! Third, copy a byte at once, if necessary
cmp/eq r5,r0
bt/s 9b
add #2,r4
mov.b @r0,r1
mov.b r1,@(r0,r4)
bra 9b
add #1,r0
case1:
!
! GHIJ KLMN OPQR --> .GHI JKLM NOPQ R...
!
! First, align to long word boundary
mov r0,r3
and r2,r3
tst r3,r3
bt/s 2f
add #-1,r4
mov #4,r2
sub r3,r2
1: dt r2
mov.b @r0+,r1
bf/s 1b
mov.b r1,@(r0,r4)
!
2: ! Second, read a long word and write a long word at once
mov.l @(r0,r4),r1
add #-7,r5
add #-4,r4
!
#ifdef __LITTLE_ENDIAN__
shll16 r1
shll8 r1
3: mov r1,r3 ! JIHG
shlr16 r3
shlr8 r3 ! xxxJ
mov.l @r0+,r1 ! NMLK
mov r1,r2
shll8 r2 ! MLKx
or r2,r3 ! MLKJ
cmp/hs r5,r0
bf/s 3b
mov.l r3,@(r0,r4)
#else
shlr16 r1
shlr8 r1
3: mov r1,r3 ! GHIJ
shll16 r3
shll8 r3 ! Jxxx
mov.l @r0+,r1 ! KLMN
mov r1,r2
shlr8 r2 ! xKLM
or r2,r3 ! JKLM
cmp/hs r5,r0
bf/s 3b ! while(r0<r5)
mov.l r3,@(r0,r4)
#endif
add #7,r5
!
! Third, copy a byte at once, if necessary
cmp/eq r5,r0
bt/s 9b
add #5,r4
add #-3,r0
bra 8b
add #-1,r4