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annotate lib/alib/memmove.as @ 3003:68a167bc476d
level3 makefiles: Order BOOTERS list like in level2
| author | Tormod Volden <debian.tormod@gmail.com> |
|---|---|
| date | Sun, 26 Oct 2014 13:02:12 +0100 |
| parents | 03f26e88b809 |
| children |
| rev | line source |
|---|---|
| 2474 | 1 ************************************** |
| 2 | |
| 3 * Memory move | |
| 4 | |
| 5 * NOTE: This routine properly moves overlapping areas of memory. | |
| 6 * Uses fast move algorithm | |
| 7 | |
| 8 * ENTRY: X=source data | |
| 9 * Y=destination | |
| 10 * D=count | |
| 11 | |
| 12 * EXIT: all registers (except CC) preserved | |
| 13 | |
| 14 nam Move Memory | |
| 15 ttl Assembler Library Module | |
| 16 | |
| 17 | |
| 18 | |
|
2782
aaba193af04f
Updated code to use lwasm/lwlink
Boisy Pitre <boisy.pitre@nuance.com>
parents:
2474
diff
changeset
|
19 section .text |
| 2474 | 20 |
| 21 MEMMOVE: | |
| 22 pshs d,x,y,u | |
| 23 std -2,s test u | |
| 24 beq exit zero count, exit | |
| 25 tfr y,u use u for dest | |
| 26 tfr d,y count in y | |
| 27 cmpu 2,s compare dest. to source (x) | |
| 28 beq exit same, no need to move | |
| 29 bhi down u>x | |
| 30 | |
| 31 up | |
| 32 bitb #1 see if odd number to move | |
| 33 beq up1 | |
| 34 lda ,x+ move odd byte | |
| 35 sta ,u+ | |
| 36 leay -1,y could be only one | |
| 37 beq exit | |
| 38 | |
| 39 up1 | |
| 40 ldd ,x++ move 2 bytes | |
| 41 std ,u++ | |
| 42 leay -2,y count down | |
| 43 bne up1 | |
| 44 bra exit | |
| 45 | |
| 46 down | |
| 47 leau d,u u=dest end (count in D) | |
| 48 leax d,x x=source end | |
| 49 | |
| 50 bitb #1 | |
| 51 beq down2 | |
| 52 lda ,-x move odd byte | |
| 53 sta ,-u | |
| 54 leay -1,y could be only one to do | |
| 55 beq exit | |
| 56 | |
| 57 down2 | |
| 58 ldd ,--x get 2 bytes | |
| 59 std ,--u move them | |
| 60 leay -2,y count down | |
| 61 bne down2 | |
| 62 | |
| 63 exit | |
| 64 puls d,x,y,u,pc | |
| 65 | |
| 66 endsect |