[Coco] 6809 disassembly help wanted

[Sean Conner]

It was thus said that the Great Allen Huffman via Coco once stated:
> 
> I know nothing about DSKCON so this will be a fun learning exercise to see
> what it does (and blog posts, no doubt).

  It's a documented Radio Shack API.  The address $C004 is the function
pointer to it (like $A000 is the function pointer to scan the keyboard), and
$C006 is the pointer to a block of memory (at location $00EA) used for
parameters to DSKCON.  The parameter block is defined as:

DCOPC                   equ     0	; operation (see below)
DCDRV                   equ     1	; drive # (0-3)
DCTRK                   equ     2	; track number (0-34)
DSEC                    equ     3	; sector number (1-18)
DCBPT                   equ     4	; trafer address
DCSTA                   equ     6	; error code after call

The defined operations:

DCOPC.restore           equ     0
DCOPC.nop               equ     1
DCOPC.read              equ     2
DCOPC.write             equ     3

and the status codes:

DCSTA.notready          equ     $80
DCSTA.writeprotect      equ     $40
DCSTA.writefault        equ     $20
DCSTA.seekerror         equ     $10
DCSTA.crcerror          equ     $08
DCSTA.lostdata          equ     $04

That's pretty much it.  

  -spc