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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2006 by Jens Arnold
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include "config.h"
.section .icode,"ax",@progbits
.align 2
.global _memmove
.type _memmove,@function
/* Moves <length> bytes of data in memory from <source> to <dest>
* Regions may overlap.
* This version is optimized for speed, and needs the corresponding memcpy
* implementation for the forward copy branch.
*
* arguments:
* r4 - destination address
* r5 - source address
* r6 - length
*
* return value:
* r0 - destination address (like ANSI version)
*
* register usage:
* r0 - data / scratch
* r1 - 2nd data / scratch
* r2 - scratch
* r3 - last long bound / adjusted start address (only if >= 11 bytes)
* r4 - current dest address
* r5 - source start address
* r6 - current source address
*
* The instruction order is devised in a way to utilize the pipelining
* of the SH1 to the max. The routine also tries to utilize fast page mode.
*/
_memmove:
cmp/hi r4,r5 /* source > destination */
bf .backward /* no: backward copy */
mov.l .memcpy_fwd,r0
jmp @r0
mov r4,r7 /* store dest for returning */
.align 2
.memcpy_fwd:
.long ___memcpy_fwd_entry
.backward:
add r6,r4 /* r4 = destination end */
mov #11,r0
cmp/hs r0,r6 /* at least 11 bytes to copy? (ensures 2 aligned longs) */
add #-8,r5 /* adjust for late decrement (max. 2 longs) */
add r5,r6 /* r6 = source end - 8 */
bf .start_b2r /* no: jump directly to byte loop */
mov #-4,r3 /* r3 = 0xfffffffc */
and r6,r3 /* r3 = last source long bound */
cmp/hi r3,r6 /* already aligned? */
bf .end_b1r /* yes: skip leading byte loop */
.loop_b1r:
mov.b @(7,r6),r0 /* load byte */
add #-1,r6 /* decrement source addr */
mov.b r0,@-r4 /* store byte */
cmp/hi r3,r6 /* runs r6 down to last long bound */
bt .loop_b1r
.end_b1r:
mov #3,r1
and r4,r1 /* r1 = dest alignment offset */
mova .jmptab_r,r0
mov.b @(r0,r1),r1 /* select appropriate main loop.. */
add r0,r1
mov r5,r3 /* copy start adress to r3 */
jmp @r1 /* ..and jump to it */
add #7,r3 /* adjust end addr for main loops doing 2 longs/pass */
/** main loops, copying 2 longs per pass to profit from fast page mode **/
/* long aligned destination (fastest) */
.align 2
.loop_do0r:
mov.l @r6,r1 /* load first long */
add #-8,r6 /* decrement source addr */
mov.l @(12,r6),r0 /* load second long */
cmp/hi r3,r6 /* runs r6 down to first or second long bound */
mov.l r0,@-r4 /* store second long */
mov.l r1,@-r4 /* store first long; NOT ALIGNED - no speed loss here! */
bt .loop_do0r
add #-4,r3 /* readjust end address */
cmp/hi r3,r6 /* first long left? */
bf .start_b2r /* no, jump to trailing byte loop */
mov.l @(4,r6),r0 /* load first long */
add #-4,r6 /* decrement source addr */
bra .start_b2r /* jump to trailing byte loop */
mov.l r0,@-r4 /* store first long */
/* word aligned destination (long + 2) */
.align 2
.loop_do2r:
mov.l @r6,r1 /* load first long */
add #-8,r6 /* decrement source addr */
mov.l @(12,r6),r0 /* load second long */
cmp/hi r3,r6 /* runs r6 down to first or second long bound */
mov.w r0,@-r4 /* store low word of second long */
xtrct r1,r0 /* extract low word of first long & high word of second long */
mov.l r0,@-r4 /* and store as long */
shlr16 r1 /* get high word of first long */
mov.w r1,@-r4 /* and store it */
bt .loop_do2r
add #-4,r3 /* readjust end address */
cmp/hi r3,r6 /* first long left? */
bf .start_b2r /* no, jump to trailing byte loop */
mov.l @(4,r6),r0 /* load first long & decrement source addr */
add #-4,r6 /* decrement source addr */
mov.w r0,@-r4 /* store low word */
shlr16 r0 /* get high word */
bra .start_b2r /* jump to trailing byte loop */
mov.w r0,@-r4 /* and store it */
/* jumptable for loop selector */
.align 2
.jmptab_r:
.byte .loop_do0r - .jmptab_r /* placed in the middle because the SH1 */
.byte .loop_do1r - .jmptab_r /* loads bytes sign-extended. Otherwise */
.byte .loop_do2r - .jmptab_r /* the last loop would be out of reach */
.byte .loop_do3r - .jmptab_r /* of the offset range. */
/* byte aligned destination (long + 1) */
.align 2
.loop_do1r:
mov.l @r6,r1 /* load first long */
add #-8,r6 /* decrement source addr */
mov.l @(12,r6),r0 /* load second long */
cmp/hi r3,r6 /* runs r6 down to first or second long bound */
mov.b r0,@-r4 /* store low byte of second long */
shlr8 r0 /* get upper 3 bytes */
mov r1,r2 /* copy first long */
shll16 r2 /* move low byte of first long all the way up, .. */
shll8 r2
or r2,r0 /* ..combine with the 3 bytes of second long.. */
mov.l r0,@-r4 /* ..and store as long */
shlr8 r1 /* get middle 2 bytes */
mov.w r1,@-r4 /* store as word */
shlr16 r1 /* get upper byte */
mov.b r1,@-r4 /* and store */
bt .loop_do1r
add #-4,r3 /* readjust end address */
.last_do13r:
cmp/hi r3,r6 /* first long left? */
bf .start_b2r /* no, jump to trailing byte loop */
nop /* alignment */
mov.l @(4,r6),r0 /* load first long */
add #-4,r6 /* decrement source addr */
mov.b r0,@-r4 /* store low byte */
shlr8 r0 /* get middle 2 bytes */
mov.w r0,@-r4 /* store as word */
shlr16 r0 /* get upper byte */
bra .start_b2r /* jump to trailing byte loop */
mov.b r0,@-r4 /* and store */
/* byte aligned destination (long + 3) */
.align 2
.loop_do3r:
mov.l @r6,r1 /* load first long */
add #-8,r6 /* decrement source addr */
mov.l @(12,r6),r0 /* load second long */
mov r1,r2 /* copy first long */
mov.b r0,@-r4 /* store low byte of second long */
shlr8 r0 /* get middle 2 bytes */
mov.w r0,@-r4 /* store as word */
shlr16 r0 /* get upper byte */
shll8 r2 /* move lower 3 bytes of first long one up.. */
or r2,r0 /* ..combine with the 1 byte of second long.. */
mov.l r0,@-r4 /* ..and store as long */
shlr16 r1 /* get upper byte of first long */
shlr8 r1
cmp/hi r3,r6 /* runs r6 down to first or second long bound */
mov.b r1,@-r4 /* ..and store */
bt .loop_do3r
bra .last_do13r /* handle first longword: reuse routine for (long + 1) */
add #-4,r3 /* readjust end address */
/* trailing byte loop: copies 0..3 bytes (or all for < 11 in total) */
.align 2
.loop_b2r:
mov.b @(7,r6),r0 /* load byte */
add #-1,r6 /* decrement source addr */
mov.b r0,@-r4 /* store byte */
.start_b2r:
cmp/hi r5,r6 /* runs r6 down to start address */
bt .loop_b2r
rts
mov r4,r0 /* return dest start address */
.end:
.size _memmove,.end-_memmove
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