Moved some assembly optimizations to the target tree

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@10318 a1c6a512-1295-4272-9138-f99709370657

1 files changed, 668 insertions, 0 deletions

diff --git a/firmware/target/coldfire/memmove-coldfire.S b/firmware/target/coldfire/memmove-coldfire.S
new file mode 100755
index 0000000000..bdd2e2e206
--- /dev/null
+++ b/firmware/target/coldfire/memmove-coldfire.S
@@ -0,0 +1,668 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * Copyright (C) 2006 by Jens Arnold
+ *
+ * All files in this archive are subject to the GNU General Public License.
+ * See the file COPYING in the source tree root for full license agreement.
+ *
+ * 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