rockbox/firmware/asm/m68k/memmove.S

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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
#define FULLSPEED /* use burst writing for word aligned destinations */
.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:
* (4,%sp) - destination address
* (8,%sp) - source address
* (12,%sp) - length
*
* return value:
* %d0 - destination address (like ANSI version)
*
* register usage:
* %a0 - current source address
* %a1 - current dest address
* %a2 - source start address (in line-copy loops)
* %d0 - source start address (byte and longword copy) / data / scratch
* %d1 - data / scratch
* %d2 - data / scratch
* %d3..%d7 - data
*
* For maximum speed this routine reads and writes whole lines using burst
* move (movem.l) where possible. For byte aligned destinations (long-1 and
* long-3) it writes longwords only. Same goes for word aligned destinations
* if FULLSPEED is undefined.
*/
memmove:
move.l (4,%sp),%a1 /* Destination */
move.l (8,%sp),%a0 /* Source */
move.l (12,%sp),%d1 /* Length */
cmp.l %a0,%a1
bhi.b .backward /* dest > src -> backward copy */
jmp __memcpy_fwd_entry
.backward:
move.l %a0,%d0 /* %d0 = source start */
add.l %d1,%a0 /* %a0 = source end */
add.l %d1,%a1 /* %a1 = destination end */
move.l %a0,%d1
and.l #0xFFFFFFFC,%d1 /* %d1 = last source long bound */
subq.l #4,%d1
cmp.l %d0,%d1 /* at least one aligned longword to copy? */
blo.w .bytes2r_start
addq.l #4,%d1 /* %d1 = last source long bound */
cmp.l %d1,%a0 /* any bytes to copy */
jls .bytes1r_end /* no: skip byte loop */
/* leading byte loop: copies 0..3 bytes */
.bytes1r_loop:
move.b -(%a0),-(%a1) /* copy byte */
cmp.l %d1,%a0 /* runs %a0 down to last long bound */
jhi .bytes1r_loop
.bytes1r_end:
moveq.l #-16,%d1
add.l %a0,%d1
and.l #0xFFFFFFF0,%d1 /* %d1 = last source line bound - 16 */
cmp.l %d0,%d1 /* at least one aligned line to copy? */
blo.w .longr_start /* no: jump to longword copy loop */
lea.l (-28,%sp),%sp /* free up some registers */
movem.l %d2-%d7/%a2,(%sp)
moveq.l #16,%d2
add.l %d2,%d1 /* %d1 = last source line bound */
move.l %d0,%a2 /* %a2 = start address */
lea.l (15,%a2),%a2 /* adjust start address for loops doing 16 bytes/pass */
move.l %a1,%d0
moveq.l #3,%d2 /* mask */
and.l %d2,%d0
jmp.l (2,%pc,%d0.l*4) /* switch (dest_addr & 3) */
bra.w .lines_do0r_start
bra.w .lines_do1r_start
bra.w .lines_do2r_start
/* bra.w .lines_do3r_start implicit */
/* byte aligned destination (long - 1): use line burst reads in main loop */
.lines_do3r_start:
moveq.l #24,%d0 /* shift count for shifting by 3 bytes */
cmp.l %d1,%a0 /* any leading longwords? */
jhi .lines_do3r_head_start /* yes: leading longword copy */
lea.l (-16,%a0),%a0
movem.l (%a0),%d3-%d6 /* load initial line */
move.l %d6,%d2 /* last longword, bytes 3210 */
move.b %d2,-(%a1) /* store byte */
lsr.l #8,%d2 /* last longword, bytes .321 */
move.w %d2,-(%a1) /* store word */
jra .lines_do3r_entry
.lines_do3r_head_start:
move.l -(%a0),%d3 /* load initial longword */
move.l %d3,%d2 /* bytes 3210 */
move.b %d2,-(%a1) /* store byte */
lsr.l #8,%d2 /* bytes .321 */
move.w %d2,-(%a1) /* store word */
jra .lines_do3r_head_entry
.lines_do3r_head_loop:
move.l %d3,%d4 /* move old longword away */
move.l -(%a0),%d3 /* load new longword */
move.l %d3,%d2
lsl.l #8,%d2 /* get bytes 210. */
or.l %d2,%d4 /* combine with old high byte */
move.l %d4,-(%a1) /* store longword */
.lines_do3r_head_entry:
lsr.l %d0,%d3 /* shift down high byte */
cmp.l %d1,%a0 /* run %a0 down to last line bound */
jhi .lines_do3r_head_loop
.lines_do3r_loop:
move.l %d3,%d7 /* move first longword of last line away */
lea.l (-16,%a0),%a0
movem.l (%a0),%d3-%d6 /* load new line */
move.l %d6,%d2
lsl.l #8,%d2 /* get bytes 210. of 4th longword */
or.l %d2,%d7 /* combine with high byte of old longword */
move.l %d7,-(%a1) /* store longword */
.lines_do3r_entry:
lsr.l %d0,%d6 /* shift down high byte */
move.l %d5,%d2
lsl.l #8,%d2 /* get bytes 210. of 3rd longword */
or.l %d2,%d6 /* combine with high byte of 4th longword */
move.l %d6,-(%a1) /* store longword */
lsr.l %d0,%d5 /* shift down high byte */
move.l %d4,%d2
lsl.l #8,%d2 /* get bytes 210. of 2nd longword */
or.l %d2,%d5 /* combine with high byte or 3rd longword */
move.l %d5,-(%a1) /* store longword */
lsr.l %d0,%d4 /* shift down high byte */
move.l %d3,%d2
lsl.l #8,%d2 /* get bytes 210. of 1st longword */
or.l %d2,%d4 /* combine with high byte of 2nd longword */
move.l %d4,-(%a1) /* store longword */
lsr.l %d0,%d3 /* shift down high byte */
cmp.l %a2,%a0 /* run %a0 down to first line bound */
jhi .lines_do3r_loop
lea.l (-12,%a2),%a2 /* readjust start address for doing longwords */
cmp.l %a2,%a0 /* any trailing longwords? */
jls .lines_do3r_tail_end /* no: just store last high byte */
.lines_do3r_tail_loop:
move.l %d3,%d4 /* move old longword away */
move.l -(%a0),%d3 /* load new longword */
move.l %d3,%d2
lsl.l #8,%d2 /* get bytes 210. */
or.l %d2,%d4 /* combine with old high byte */
move.l %d4,-(%a1) /* store longword */
lsr.l %d0,%d3 /* shift down high byte */
cmp.l %a2,%a0 /* run %a0 down to first long bound */
jhi .lines_do3r_tail_loop
.lines_do3r_tail_end:
move.b %d3,-(%a1) /* store shifted-down high byte */
jra .linesr_end
/* byte aligned destination (long - 3): use line burst reads in main loop */
.lines_do1r_start:
moveq.l #24,%d0 /* shift count for shifting by 3 bytes */
cmp.l %d1,%a0 /* any leading longwords? */
jhi .lines_do1r_head_start /* yes: leading longword copy */
lea.l (-16,%a0),%a0
movem.l (%a0),%d3-%d6 /* load initial line */
move.b %d6,-(%a1) /* store low byte of last longword */
jra .lines_do1r_entry
.lines_do1r_head_start:
move.l -(%a0),%d3 /* load initial longword */
move.b %d3,-(%a1) /* store low byte */
jra .lines_do1r_head_entry
.lines_do1r_head_loop:
move.l %d3,%d4 /* move old longword away */
move.l -(%a0),%d3 /* load new longword */
move.l %d3,%d2
lsl.l %d0,%d2 /* get low byte */
or.l %d2,%d4 /* combine with old bytes .321 */
move.l %d4,-(%a1) /* store longword */
.lines_do1r_head_entry:
lsr.l #8,%d3 /* get bytes .321 */
cmp.l %d1,%a0 /* run %a0 down to last line bound */
jhi .lines_do1r_head_loop
.lines_do1r_loop:
move.l %d3,%d7 /* move first longword of old line away */
lea.l (-16,%a0),%a0
movem.l (%a0),%d3-%d6 /* load new line */
move.l %d6,%d2
lsl.l %d0,%d2 /* get low byte of 4th longword */
or.l %d2,%d7 /* combine with bytes .321 of old longword */
move.l %d7,-(%a1) /* store longword */
.lines_do1r_entry:
lsr.l #8,%d6 /* get bytes .321 */
move.l %d5,%d2
lsl.l %d0,%d2 /* get low byte of 3rd longword */
or.l %d2,%d6 /* combine with bytes .321 of 4th longword */
move.l %d6,-(%a1) /* store longword */
lsr.l #8,%d5 /* get bytes .321 */
move.l %d4,%d2
lsl.l %d0,%d2 /* get low byte of 2nd longword */
or.l %d2,%d5 /* combine with bytes .321 of 3rd longword */
move.l %d5,-(%a1) /* store longword */
lsr.l #8,%d4 /* get bytes .321 */
move.l %d3,%d2
lsl.l %d0,%d2 /* get low byte of 1st longword */
or.l %d2,%d4 /* combine with bytes .321 of 2nd longword */
move.l %d4,-(%a1) /* store longword */
lsr.l #8,%d3 /* get bytes .321 */
cmp.l %a2,%a0 /* run %a0 down to first line bound */
jhi .lines_do1r_loop
lea.l (-12,%a2),%a2 /* readjust start address for doing longwords */
cmp.l %a2,%a0 /* any trailing longwords? */
jls .lines_do1r_tail_end /* no: just store last high byte */
.lines_do1r_tail_loop:
move.l %d3,%d4 /* move old longword away */
move.l -(%a0),%d3 /* load new longword */
move.l %d3,%d2
lsl.l %d0,%d2 /* get low byte */
or.l %d2,%d4 /* combine with old bytes .321 */
move.l %d4,-(%a1) /* store longword */
lsr.l #8,%d3 /* get bytes .321 */
cmp.l %a2,%a0 /* run %a0 down to first long bound */
jhi .lines_do1r_tail_loop
.lines_do1r_tail_end:
move.w %d3,-(%a1) /* store word 21 */
swap %d3
move.b %d3,-(%a1) /* store byte 3 */
jra .linesr_end
/* long aligned destination (line - 0/4/8/12): head */
.lines_do0r_head_loop:
move.l -(%a0),-(%a1) /* copy longword */
.lines_do0r_start:
cmp.l %d1,%a0 /* run %a0 down to last line bound */
jhi .lines_do0r_head_loop
.lines_do0r_head_end:
move.l %a1,%d1
lsr.l #2,%d1
moveq.l #3,%d0 /* mask */
and.l %d0,%d1
moveq.l #16,%d0 /* address decrement for one main loop pass */
jmp.l (2,%pc,%d1.l*2) /* switch ((dest_addr >> 2) & 3) */
bra.b .lines_lo0r_start
bra.b .lines_lo4r_start
bra.b .lines_lo8r_start
/* bra.b .lines_lo12r_start implicit */
/* long aligned destination (line - 4): use line bursts in the loop */
.lines_lo12r_start:
sub.l %d0,%a0
movem.l (%a0),%d1-%d4 /* load initial line */
move.l %d4,-(%a1) /* store 4th longword */
move.l %d3,-(%a1) /* store 3rd longword */
move.l %d2,-(%a1) /* store 2nd longword */
cmp.l %a2,%a0 /* any full lines? */
jls .lines_lo12r_end /* no: skip main loop */
.lines_lo12r_loop:
move.l %d1,%d5 /* move first longword of old line away */
sub.l %d0,%a0
movem.l (%a0),%d1-%d4 /* load new line */
sub.l %d0,%a1
movem.l %d2-%d5,(%a1) /* store line (1 old + 3 new longwords */
cmp.l %a2,%a0 /* run %a0 down to first line bound */
jhi .lines_lo12r_loop
jra .lines_lo12r_end /* handle trailing longwords */
/* line aligned destination: use line bursts in the loop */
.lines_lo0r_start:
.lines_lo0r_loop:
sub.l %d0,%a0
movem.l (%a0),%d1-%d4 /* load line */
sub.l %d0,%a1
movem.l %d1-%d4,(%a1) /* store line */
cmp.l %a2,%a0 /* run %a0 down to first line bound */
jhi .lines_lo0r_loop
jra .lines_lo0r_end /* handle trailing longwords */
/* long aligned destination (line - 8): use line bursts in the loop */
.lines_lo8r_start:
sub.l %d0,%a0
movem.l (%a0),%d1-%d4 /* load initial line */
move.l %d4,-(%a1) /* store 4th longword */
move.l %d3,-(%a1) /* store 3rd longword */
cmp.l %a2,%a0 /* any full lines? */
jls .lines_lo8r_end /* no: skip main loop */
.lines_lo8r_loop:
move.l %d2,%d6 /* move first 2 longwords of old line away */
move.l %d1,%d5
sub.l %d0,%a0
movem.l (%a0),%d1-%d4 /* load new line */
sub.l %d0,%a1
movem.l %d3-%d6,(%a1) /* store line (2 old + 2 new longwords */
cmp.l %a2,%a0 /* run %a0 down to first line bound */
jhi .lines_lo8r_loop
jra .lines_lo8r_end /* handle trailing longwords */
/* long aligned destination (line - 12): use line bursts in the loop */
.lines_lo4r_start:
sub.l %d0,%a0
movem.l (%a0),%d1-%d4 /* load initial line */
move.l %d4,-(%a1) /* store 4th longword */
cmp.l %a2,%a0 /* any full lines? */
jls .lines_lo4r_end /* no: skip main loop */
.lines_lo4r_loop:
move.l %d3,%d7 /* move first 3 longwords of old line away */
move.l %d2,%d6
move.l %d1,%d5
sub.l %d0,%a0
movem.l (%a0),%d1-%d4 /* load new line */
sub.l %d0,%a1
movem.l %d4-%d7,(%a1) /* store line (3 old + 1 new longwords */
cmp.l %a2,%a0 /* run %a0 down to first line bound */
jhi .lines_lo4r_loop
/* long aligned destination (line - 0/4/8/12): tail */
.lines_lo4r_end:
move.l %d3,-(%a1) /* store 3rd last longword */
.lines_lo8r_end:
move.l %d2,-(%a1) /* store 2nd last longword */
.lines_lo12r_end:
move.l %d1,-(%a1) /* store last longword */
.lines_lo0r_end:
lea.l (-12,%a2),%a2 /* readjust end address for doing longwords */
cmp.l %a2,%a0 /* any trailing longwords? */
jls .linesr_end /* no: get outta here */
.lines_do0r_tail_loop:
move.l -(%a0),-(%a1) /* copy longword */
cmp.l %a2,%a0 /* run %a0 down to first long bound */
jhi .lines_do0r_tail_loop
jra .linesr_end
#ifdef FULLSPEED
/* word aligned destination (line - 2/6/10/14): head */
.lines_do2r_start:
cmp.l %d1,%a0 /* any leading longwords? */
jls .lines_do2r_selector /* no: jump to mainloop selector */
move.l -(%a0),%d3 /* load initial longword */
move.w %d3,-(%a1) /* store low word */
cmp.l %d1,%a0 /* any more longwords? */
jls .lines_do2r_head_end /* no: skip head loop */
.lines_do2r_head_loop:
move.l %d3,%d4 /* move old longword away */
move.l -(%a0),%d3 /* load new longword */
move.w %d3,%d4 /* combine low word with old high word */
swap %d4 /* swap words */
move.l %d4,-(%a1) /* store longword */
cmp.l %d1,%a0 /* run %a0 down to last line bound */
jhi .lines_do2r_head_loop
.lines_do2r_head_end:
swap %d3 /* get high word */
move.w %d3,-(%a1) /* and store it */
.lines_do2r_selector:
move.l %a1,%d1
lsr.l #2,%d1
moveq.l #3,%d0 /* mask */
and.l %d0,%d1
moveq.l #16,%d7 /* address decrement for one main loop pass */
jmp.l (2,%pc,%d1.l*4) /* switch ((dest_addr >> 2) & 3) */
bra.w .lines_lo2r_start
bra.w .lines_lo6r_start
bra.w .lines_lo10r_start
/* bra.w .lines_lo14r_start implicit */
/* word aligned destination (line - 2): use line bursts in the loop */
.lines_lo14r_start:
sub.l %d7,%a0
movem.l (%a0),%d0-%d3 /* load initial line */
move.w %d3,-(%a1) /* store last low word */
move.w %d2,%d3 /* combine 3rd low word with 4th high word */
swap %d3 /* swap words of 3rd long */
move.w %d1,%d2 /* combine 2nd low word with 3rd high word */
swap %d2 /* swap words of 2nd long */
move.w %d0,%d1 /* combine 1st low word with 2nd high word */
swap %d1 /* swap words of 1st long */
move.l %d3,-(%a1) /* store 3rd longword */
move.l %d2,-(%a1) /* store 2nd longword */
move.l %d1,-(%a1) /* store 1st longword */
cmp.l %a2,%a0 /* any full lines? */
jls .lines_lo14r_end /* no: skip main loop */
.lines_lo14r_loop:
move.l %d0,%d4 /* move first longword of old line away */
sub.l %d7,%a0
movem.l (%a0),%d0-%d3 /* load line */
move.w %d3,%d4 /* combine 4th low word with old high word */
swap %d4 /* swap words of 4th long */
move.w %d2,%d3 /* combine 3rd low word with 4th high word */
swap %d3 /* swap words of 3rd long */
move.w %d1,%d2 /* combine 2nd low word with 3rd high word */
swap %d2 /* swap words of 2nd long */
move.w %d0,%d1 /* combine 1st low word with 2nd high word */
swap %d1 /* swap words of 1st long */
sub.l %d7,%a1
movem.l %d1-%d4,(%a1) /* store line */
cmp.l %a2,%a0 /* run %a0 down to first line bound */
jhi .lines_lo14r_loop
jra .lines_lo14r_end /* handle trailing longwords */
/* word aligned destination (line - 6): use line bursts in the loop */
.lines_lo10r_start:
sub.l %d7,%a0
movem.l (%a0),%d0-%d3 /* load initial line */
move.w %d3,-(%a1) /* store last low word */
move.w %d2,%d3 /* combine 3rd low word with 4th high word */
swap %d3 /* swap words of 3rd long */
move.w %d1,%d2 /* combine 2nd low word with 3rd high word */
swap %d2 /* swap words of 2nd long */
move.l %d3,-(%a1) /* store 3rd longword */
move.l %d2,-(%a1) /* store 2nd longword */
jra .lines_lo10r_entry /* jump into main loop */
.lines_lo10r_loop:
move.l %d0,%d4 /* move first 2 longwords of old line away */
move.l %d1,%d5
sub.l %d7,%a0
movem.l (%a0),%d0-%d3 /* load line */
move.w %d3,%d4 /* combine 4th low word with old high word */
swap %d4 /* swap words of 4th long */
move.w %d2,%d3 /* combine 3rd low word with 4th high word */
swap %d3 /* swap words of 3rd long */
move.w %d1,%d2 /* combine 2nd low word with 3rd high word */
swap %d2 /* swap words of 2nd long */
sub.l %d7,%a1
movem.l %d2-%d5,(%a1) /* store line */
.lines_lo10r_entry:
move.w %d0,%d1 /* combine 1st low word with 2nd high word */
swap %d1 /* swap words of 1st long */
cmp.l %a2,%a0 /* run %a0 down to first line bound */
jhi .lines_lo10r_loop
jra .lines_lo10r_end /* handle trailing longwords */
/* word aligned destination (line - 10): use line bursts in the loop */
.lines_lo6r_start:
sub.l %d7,%a0
movem.l (%a0),%d0-%d3 /* load initial line */
move.w %d3,-(%a1) /* store last low word */
move.w %d2,%d3 /* combine 3rd low word with 4th high word */
swap %d3 /* swap words of 3rd long */
move.l %d3,-(%a1) /* store 3rd longword */
jra .lines_lo6r_entry /* jump into main loop */
.lines_lo6r_loop:
move.l %d0,%d4 /* move first 3 longwords of old line away */
move.l %d1,%d5
move.l %d2,%d6
sub.l %d7,%a0
movem.l (%a0),%d0-%d3 /* load line */
move.w %d3,%d4 /* combine 4th low word with old high word */
swap %d4 /* swap words of 4th long */
move.w %d2,%d3 /* combine 3rd low word with 4th high word */
swap %d3 /* swap words of 3rd long */
sub.l %d7,%a1
movem.l %d3-%d6,(%a1) /* store line */
.lines_lo6r_entry:
move.w %d1,%d2 /* combine 2nd low word with 3rd high word */
swap %d2 /* swap words of 2nd long */
move.w %d0,%d1 /* combine 1st low word with 2nd high word */
swap %d1 /* swap words of 1st long */
cmp.l %a2,%a0 /* run %a0 down to first line bound */
jhi .lines_lo6r_loop
jra .lines_lo6r_end /* handle trailing longwords */
/* word aligned destination (line - 14): use line bursts in the loop */
.lines_lo2r_start:
sub.l %d7,%a0
movem.l (%a0),%d0-%d3 /* load initial line */
move.w %d3,-(%a1) /* store last low word */
jra .lines_lo2r_entry /* jump into main loop */
.lines_lo2r_loop:
move.l %d0,%d4 /* move old line away */
move.l %d1,%d5
move.l %d2,%d6
move.l %d3,%d7
lea.l (-16,%a0),%a0
movem.l (%a0),%d0-%d3 /* load line */
move.w %d3,%d4 /* combine 4th low word with old high word */
swap %d4 /* swap words of 4th long */
lea.l (-16,%a1),%a1
movem.l %d4-%d7,(%a1) /* store line */
.lines_lo2r_entry:
move.w %d2,%d3 /* combine 3rd low word with 4th high word */
swap %d3 /* swap words of 3rd long */
move.w %d1,%d2 /* combine 2nd low word with 3rd high word */
swap %d2 /* swap words of 2nd long */
move.w %d0,%d1 /* combine 1st low word with 2nd high word */
swap %d1 /* swap words of 1st long */
cmp.l %a2,%a0 /* run %a0 down to first line bound */
jhi .lines_lo2r_loop
/* word aligned destination (line - 2/6/10/14): tail */
.lines_lo2r_end:
move.l %d3,-(%a1) /* store third last longword */
.lines_lo6r_end:
move.l %d2,-(%a1) /* store second last longword */
.lines_lo10r_end:
move.l %d1,-(%a1) /* store last longword */
.lines_lo14r_end:
lea.l (-12,%a2),%a2 /* readjust start address for doing longwords */
cmp.l %a2,%a0 /* any trailing longwords? */
jls .lines_do2r_tail_end /* no: skip tail loop */
.lines_do2r_tail_loop:
move.l %d0,%d1 /* move old longword away */
move.l -(%a0),%d0 /* load new longword */
move.w %d0,%d1 /* combine low word with old high word */
swap %d1 /* swap words */
move.l %d1,-(%a1) /* store longword */
cmp.l %a2,%a0 /* run %a0 down to first long bound */
jhi .lines_do2r_tail_loop
.lines_do2r_tail_end:
swap %d0 /* get final high word */
move.w %d0,-(%a1) /* store it */
/* jra .linesr_end implicit */
#else /* !FULLSPEED */
/* word aligned destination (long - 2): use line burst reads in the loop */
.lines_do2r_start:
cmp.l %d1,%a0 /* any leading longwords? */
jhi .lines_do2r_head_start /* yes: leading longword copy */
lea.l (-16,%a0),%a0
movem.l (%a0),%d3-%d6 /* load initial line */
move.w %d6,-(%a1) /* store last low word */
jra .lines_do2r_entry /* jump into main loop */
.lines_do2r_head_start:
move.l -(%a0),%d3 /* load initial longword */
move.w %d3,-(%a1) /* store low word */
cmp.l %d1,%a0 /* any full longword? */
jls .lines_do2r_loop /* no: skip head loop */
.lines_do2r_head_loop:
move.l %d3,%d4 /* move old longword away */
move.l -(%a0),%d3 /* load new longword */
move.w %d3,%d4 /* combine low word with old high word */
swap %d4 /* swap words */
move.l %d4,-(%a1) /* store longword */
cmp.l %d1,%a0 /* run %a0 down to last line bound */
jhi .lines_do2r_head_loop
.lines_do2r_loop:
move.l %d3,%d7 /* move first longword of old line away */
lea.l (-16,%a0),%a0
movem.l (%a0),%d3-%d6 /* load line */
move.w %d6,%d7 /* combine 4th low word with old high word */
swap %d7 /* swap words of 4th long */
move.l %d7,-(%a1) /* store 4th longword */
.lines_do2r_entry:
move.w %d5,%d6 /* combine 3rd low word with 4th high word */
swap %d6 /* swap words of 3rd long */
move.l %d6,-(%a1) /* store 3rd longword */
move.w %d4,%d5 /* combine 2nd low word with 3rd high word */
swap %d5 /* swap words of 2nd long */
move.l %d5,-(%a1) /* store 2nd longword */
move.w %d3,%d4 /* combine 1st low word with 2nd high word */
swap %d4 /* swap words of 1st long */
move.l %d4,-(%a1) /* store 1st longword */
cmp.l %a2,%a0 /* run %a0 down to first line bound */
jhi .lines_do2r_loop
.lines_do2r_end:
lea.l (-12,%a2),%a2 /* readjust start address for doing longwords */
cmp.l %a2,%a0 /* any trailing longwords? */
jls .lines_do2r_tail_end /* no: skip tail loop */
.lines_do2r_tail_loop:
move.l %d3,%d4 /* move old longword away */
move.l -(%a0),%d3 /* load new longword */
move.w %d3,%d4 /* combine low word with old high word */
swap %d4 /* swap words */
move.l %d4,-(%a1) /* store longword */
cmp.l %a2,%a0 /* run %a0 down to first long bound */
jhi .lines_do2r_tail_loop
.lines_do2r_tail_end:
swap %d3 /* get final high word */
move.w %d3,-(%a1) /* store it */
/* jra .linesr_end implicit */
#endif /* !FULLSPEED */
.linesr_end:
subq.l #3,%a2 /* readjust end address */
move.l %a2,%d0 /* start address in %d0 again */
movem.l (%sp),%d2-%d7/%a2 /* restore registers */
lea.l (28,%sp),%sp
jra .bytes2r_start /* jump to trailing byte loop */
.longr_start:
addq.l #3,%d0 /* adjust start address for doing 4 bytes/ pass */
/* longword copy loop - no lines */
.longr_loop:
move.l -(%a0),-(%a1) /* copy longword (write can be unaligned) */
cmp.l %d0,%a0 /* runs %a0 down to first long bound */
jhi .longr_loop
subq.l #3,%d0 /* readjust start address */
cmp.l %d0,%a0 /* any bytes left? */
jls .bytes2r_end /* no: skip trailing byte loop */
/* trailing byte loop */
.bytes2r_loop:
move.b -(%a0),-(%a1) /* copy byte */
.bytes2r_start:
cmp.l %d0,%a0 /* runs %a0 down to start address */
jhi .bytes2r_loop
.bytes2r_end:
rts /* returns start address */
.end:
.size memmove,.end-memmove