Unknown 8085 opcodes
Henrik Stahl
henrik at datalinesweden.se
Wed Jan 11 11:17:24 CST 2017
Hi Adrian
It looks like text, not code.
54 T
65 e
6c l
65 e
70 p
68 h
6f o
6e n
65 e
20 space
Henrik
Adrian Graham skrev 2017-01-11 18:10:
> Hi folks,
>
> Any 8085 assembler geeks in the house?
>
> Official Intel docs don't seem to be helping with this one, I have 8085 and
> D8741A peripheral controller dumps both containing several opcodes that two
> disassemblers aren't recognising and any docs I've been looking through for
> either 8085 instructions or the UPI instruction set don't seem to feature
> them either.
>
> The codes are 0x08, 0x10, 0x18, 0x28, 0x38,0xD9, 0xDD and 0xED.
>
> 0x08 nearly always follows a 0x01 LXI B instruction, the others don't seem
> to have an obvious pattern.
>
> I've pondered if 0x10 is INC @R0 because the binary for that is 0001 000x
> where x is either 0 or 1.
> By the same reasoning 0xD9 could be XRL A,R1 (opcode 11011xxx) and 0xDD
> could be XRL A,R5 but can't match the others. Also the surrounding code
> doesn't mention those registers.
>
> Example 8085 code fragment:
>
> 3440 1792 09 DAD B
> 3441 1793 01 01 08 LXI B,0801H
> 3442 1796 08 UNRECOGNIZED
> 3443 1797 12 STAX D
> 3444 1798 0D DCR C
> 3445 1799 54 MOV D,H
> 3446 179A 65 MOV H,L
> 3447 179B 6C MOV L,H
> 3448 179C 65 MOV H,L
> 3449 179D 70 MOV M,B
> 3450 179E 68 MOV L,B
> 3451 179F 6F MOV L,A
> 3452 17A0 6E MOV L,M
> 3453 17A1 65 MOV H,L
> 3454 17A2 20 RIM
> 3455 17A3 44 MOV B,H
> 3456 17A4 65 MOV H,L
> 3457 17A5 74 MOV M,H
> 3458 17A6 61 MOV H,C
> 3459 17A7 69 MOV L,C
> 3460 17A8 6C MOV L,H
> 3461 17A9 73 MOV M,E
> 3462 17AA 01 04 05 LXI B,0504H
> 3463 17AD 08 UNRECOGNIZED
> 3464 17AE 17 RAL
> 3465 17AF 53 MOV D,E
> 3466 17B0 65 MOV H,L
> 3467 17B1 6C MOV L,H
> 3468 17B2 65 MOV H,L
> 3469 17B3 63 MOV H,E
> 3470 17B4 74 MOV M,H
> 3471 17B5 20 RIM
>
> Cheers!
>
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