[Coco] F9dasm and bad 6809 op codes

Allen Huffman alsplace at pobox.com
Fri Nov 21 19:12:48 EST 2025


Is there such an op code as DEY or PSHX?

Both are generated by the f9dasm disassembler:

        LDY     M3AFD                    ;3A04: 10 BE 3A FD    '..:.'
Z3A08   DEY                              ;3A08: 31 3F          '1?'
        BNE     GETKEY                   ;3A0A: 26 05          '&.'

…then later…

        LEAX    -$05,X                   ;3A6D: 30 1B          '0.'
        PSHX                             ;3A6F: 34 10          '4.'
        LDX     #DCOPC                   ;3A71: 8E 00 EA       '...'

Any op code but experts out there?  The 31 seems to be LEAY $3F,Y, perhaps. Unsure about the other. The document I am looking at is not OCR’d so I cannot do a search in it.

		- A

Code:

https://github.com/Arakula/f9dasm

My files:

https://github.com/allenhuffman/SubEthaSoftware/tree/main/OS-9/MultiBoot/asm

The dat file (one directory higher) also exists as data numbers in my C program, so I used a Python script to spit those data numbers into multiboot.bin and am working from that.

Earlier, I was doing it from an Intel HEX file. I was having problems there, too, so switched to the .bin approach - same issues.

Just me?

		— A



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