> > All the dicussions of the Supercharger have been good so far, but what happens here:
> >
> > F000 ldx #$3f
> > F002 cmp $f000,x ;Write data = $3f
> > F005 NOP
> > F006 lda $ff7b ;Write $3f to $f7b
> >
> > Wouldn't the SC see the opcode fetch from address F002 as Write data = $02 and the start of a ram write?
>
> Humm... good question.. I'd say it works like this:
>
> cycle action
> 0 load opcode for ldx from location f000
> write value is set to 00 (since we are accessing f000)
> 1 load operand from f001 (3f)
>
> 2 load opcode from f002 for cmp
> 3 load low byte 00 from f003
> 4 load high byte f0 from f004, add x to low byte
> 5 load operand from f03f
>
> 6 load opcode from f005 for nop
> 7 do something but nothing ...
>
> So I would say a poke(f03f,00) at cycle 5 or poke(f005,00) at cycle 6
> occurs.
I believe the piece of code I gave is a valid SC RAM write, I am assuming that it will write $3F to $f7b. I am working under the assumption that RAM writes work the same if the are executing in the $f000-$f0ff range as any other location. I may be incorrect in this assumption.
Dan Boris
--
Archives available at http://www.biglist.com/lists/stella/archives/
E-mail UNSUBSCRIBE in the body to stella-request@xxxxxxxxxxx to be removed.
