Date   : Sat, 04 Apr 2009 08:52:21 +0100
From   : zeem.uk@... (Alex Taylor)
Subject: A quick question about EPROM programming

2009/4/3 Anders Carlsson <anders.carlsson@...>:

> Now I'll try to figure out how to adopt the ROM, and since both
> computers are 6502 based, in theory the code should be executable
> although it will try to reference ROM and hardware not existing.

I'd guess that if you could build an 8271-based disk interface mapped
somewhere in memory, then the DFS should be patchable with those (and
other C64-specific) memory locations and routines, and possibly work.
It might not be easy though, and possibly require modifying from
source and recompiling, given the totally different underlying OS in
the 64.

> Next week I'll try the opposite, stuck some C64 utility ROM into
> my BBC Micro and see if it picks it up. :-P

Unlikely because the BBC's OS expects a particular header in the ROM
and it won't do anything if it's not there.

>From memory (I read a book on the subject a while back), the C64 will
just jump in where an expansion ROM is present (e.g. a cartridge) when
certain expansion bus pins are grounded. Although that doesn't explain
why your C64 started up in BASIC.

-- 
Alex Taylor