summaryrefslogtreecommitdiffstats
path: root/firmware/common/memmove_a.S
blob: d7421333dfce2662576d1a286f8cf54b70e6614c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
/***************************************************************************
 *             __________               __   ___.
 *   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

#if CONFIG_CPU == SH7034
    .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
#elif defined(CPU_COLDFIRE)
#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
#endif