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| /* SPDX-License-Identifier: GPL-2.0 */
| /* $Id: memcpy.S,v 1.3 2001/07/27 11:50:52 gniibe Exp $
| *
| * "memcpy" implementation of SuperH
| *
| * Copyright (C) 1999 Niibe Yutaka
| *
| */
|
| /*
| * void *memcpy(void *dst, const void *src, size_t n);
| * No overlap between the memory of DST and of SRC are assumed.
| */
|
| #include <linux/linkage.h>
| ENTRY(memcpy)
| tst r6,r6
| bt/s 9f ! if n=0, do nothing
| mov r4,r0
| sub r4,r5 ! From here, r5 has the distance to r0
| add r6,r0 ! From here, r0 points the end of copying point
| mov #12,r1
| cmp/gt r6,r1
| bt/s 7f ! if it's too small, copy a byte at once
| add #-1,r5
| add #1,r5
| ! From here, r6 is free
| !
| ! r4 --> [ ... ] DST [ ... ] SRC
| ! [ ... ] [ ... ]
| ! : :
| ! r0 --> [ ... ] r0+r5 --> [ ... ]
| !
| !
| mov r5,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
| 7: mov r4,r2
| add #1,r2
| 8:
| cmp/hi r2,r0
| mov.b @(r0,r5),r1
| bt/s 8b ! while (r0>r2)
| mov.b r1,@-r0
| 9:
| rts
| nop
|
| 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 #-4,r5
| add #3,r5
| 1: dt r3
| mov.b @(r0,r5),r1
| bf/s 1b
| mov.b r1,@-r0
| !
| add #-3,r5
| 2: ! Second, copy a long word at once
| mov r4,r2
| add #7,r2
| 3: mov.l @(r0,r5),r1
| cmp/hi r2,r0
| bt/s 3b
| mov.l r1,@-r0
| !
| ! Third, copy a byte at once, if necessary
| cmp/eq r4,r0
| bt/s 9b
| add #3,r5
| bra 8b
| add #-6,r2
|
| case1:
| !
| ! 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,r5
| 1: dt r3
| mov.b @(r0,r5),r1
| bf/s 1b
| mov.b r1,@-r0
| !
| 2: ! Second, read a long word and write a long word at once
| mov.l @(r0,r5),r1
| add #-4,r5
| mov r4,r2
| add #7,r2
| !
| #ifdef __LITTLE_ENDIAN__
| 3: mov r1,r3 ! RQPO
| shll16 r3
| shll8 r3 ! Oxxx
| mov.l @(r0,r5),r1 ! NMLK
| mov r1,r6
| shlr8 r6 ! xNML
| or r6,r3 ! ONML
| cmp/hi r2,r0
| bt/s 3b
| mov.l r3,@-r0
| #else
| 3: mov r1,r3 ! OPQR
| shlr16 r3
| shlr8 r3 ! xxxO
| mov.l @(r0,r5),r1 ! KLMN
| mov r1,r6
| shll8 r6 ! LMNx
| or r6,r3 ! LMNO
| cmp/hi r2,r0
| bt/s 3b
| mov.l r3,@-r0
| #endif
| !
| ! Third, copy a byte at once, if necessary
| cmp/eq r4,r0
| bt/s 9b
| add #4,r5
| bra 8b
| add #-6,r2
|
| case2:
| !
| ! GHIJ KLMN OPQR --> ..GH IJKL MNOP QR..
| !
| ! First, align to word boundary
| tst #1,r0
| bt/s 2f
| add #-1,r5
| mov.b @(r0,r5),r1
| mov.b r1,@-r0
| !
| 2: ! Second, read a word and write a word at once
| add #-1,r5
| mov r4,r2
| add #3,r2
| !
| 3: mov.w @(r0,r5),r1
| cmp/hi r2,r0
| bt/s 3b
| mov.w r1,@-r0
| !
| ! Third, copy a byte at once, if necessary
| cmp/eq r4,r0
| bt/s 9b
| add #1,r5
| mov.b @(r0,r5),r1
| rts
| mov.b r1,@-r0
|
| case3:
| !
| ! 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,r5
| 1: dt r3
| mov.b @(r0,r5),r1
| bf/s 1b
| mov.b r1,@-r0
| !
| 2: ! Second, read a long word and write a long word at once
| add #-2,r5
| mov.l @(r0,r5),r1
| add #-4,r5
| mov r4,r2
| add #7,r2
| !
| #ifdef __LITTLE_ENDIAN__
| 3: mov r1,r3 ! RQPO
| shll8 r3 ! QPOx
| mov.l @(r0,r5),r1 ! NMLK
| mov r1,r6
| shlr16 r6
| shlr8 r6 ! xxxN
| or r6,r3 ! QPON
| cmp/hi r2,r0
| bt/s 3b
| mov.l r3,@-r0
| #else
| 3: mov r1,r3 ! OPQR
| shlr8 r3 ! xOPQ
| mov.l @(r0,r5),r1 ! KLMN
| mov r1,r6
| shll16 r6
| shll8 r6 ! Nxxx
| or r6,r3 ! NOPQ
| cmp/hi r2,r0
| bt/s 3b
| mov.l r3,@-r0
| #endif
| !
| ! Third, copy a byte at once, if necessary
| cmp/eq r4,r0
| bt/s 9b
| add #6,r5
| bra 8b
| add #-6,r2
|
|
