[Coco] GFL football 2 on Cocoflash

Arthur Flexser flexser at fiu.edu
Tue Jan 16 15:05:41 EST 2018


I can definitely confirm it, as I tried this out a decade or two ago on a
real CoCo 3.  You can also view the code of the patcher program in the
internal ROM, which runs at startup, this way, even though it is normally
not in the memory map.  POKE &HFFA3, &H3C will put the patcher at
$6000-7FFF.  (Move the stack out of the way first with CLEAR 200,&H6000.)
Also may or may not require going to ROM mode to see the patcher code.

Art

On Mon, Jan 15, 2018 at 3:02 AM, RETRO Innovations <go4retro at go4retro.com>
wrote:

> On 1/15/2018 1:17 AM, Arthur Flexser wrote:
>
>> The ROM contents of $FFF0-FFFF can be read by moving the ROM segment to a
>> different memory location using the MMU.
>>
> Can someone to try this and confirm it, because the COco3 schematic does
> not show this being possible.  The MMU address lines only appear at the Z
> address lines (DRAM multiplexed address lines), and the ROM is directly
> connected to A0-A14.  It *may* be possible to remap the ROM to 0-$7fff, but
> I don't think you can use the MMU to do it.
>
> JIm
>
>
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