boisy at tee-boy.com
Fri Mar 6 16:25:25 EST 2009
On Mar 6, 2009, at 3:15 PM, Robert Gault wrote:
> 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.
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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