[Coco] F9dasm and bad 6809 op codes

[Allen Huffman]

> On Nov 21, 2025, at 7:16 PM, Sean Conner via Coco <coco at maltedmedia.com> wrote:
> 
>  Might need some better tools.  Here's what I was able to do with the
> second array.  It seems to assume SECB, so for a Coco 3.

Awesome! I’ll compare notes.

I have been working through the f9dasm I have, labeling things as I figure them out:

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

Really enjoying the “info” capabilities of this disassembler. You make a second file and can put in notes like label addresses and such, then it starts using your labels for those memory locations.

As I go through the code, I keep adding more to that info file:

; ROM
label   8C1B DLOAD
label   95C9 VDGPATCH 
label   A000 POLCAT
label   A002 CHROUT
label   A928 CLS
label   C004 DSKCON
label   D709 IOERROR
label   F652 COL32
label   FF22 VDGPIA
label   FFBC FOREPAL32

Those are various places in ROMs it patches or jumps into. Elsewhere, I have been slowing giving names to Terry’s routines.

label   3900 START
label   3907 CPYLOOP 
label   3A08 DLYLOOP
label   3A11 GETKEY
label   3A32 UP
label   3ACF RETURN
label   3A49 DOWN
label   3A67 ENTER
label   3A95 CPYLOOP2
label   3AA8 GODOS
…etc…

Coming along nicely, though I have had to use my C code for reference to understand where things are getting loaded.

Still a lot of mystery here.

		- A