[Coco] DriveWire

[Boisy Pitre]

On Mar 6, 2009, at 3:15 PM, Robert Gault wrote:

> Boisy,
>
> I've a question regards the new DriveWire ROM. I've been able to  
> boot with it installed in both MESS and VCC as it is easy to replace  
> the ROM images. I do have an EPROM programmer but thought I would  
> first try the following with a real 6309 Coco3.
>
> The original RGBDOS could be offset loaded into RAM (say $3000) and  
> then moved into the correct location with a short ml program. RGBDOS  
> booted and could be used as a test case this way before burning a ROM.
> I tried that with the new drivewire ROM and it won't work, the Coco3  
> crashes. Here is the ml code that moves the ROM. Any reason why this  
> shouldn't work?
>
> org $7000
> start orcc #$50
> ldx #$3000    where the ROM was offset loaded
> ldy #$c000
> a@ ldd ,x++
> std ,y++
> cmpx #$e000
> blo a@
> jmp $c002
> end start
>
> And yes, I did add the header and footer to turn the ROM into a  
> LOADM binary.

Robert,

Just to be clear: you're wrapping a LOADM header and footer around the  
image and place it on a disk, doing a LOADM (it now resides at $3000),  
LOADM your patch code, then EXEC &H7000.

Seems to me you would be writing right over the existing Disk BASIC  
(or RGBDOS) ROM at $C000, and that could certainly cause a crash??

>
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