Re: [stella] 6502 hardware register writes

["John Saeger" <john@xxxxxxxxxxx>]

 

----- Original Message -----

From: AutismUK@xxxxxxx

 

A26 (the basis of Z26) used a scam whereby it checksummed the
data transfer and timing to the TIA and its current state, and if the
checksum didn't change the screen didn't either,

 

This was particularly effective when video writes were expensive.  Who knows?  If there is some expensive calculation required to update a pixel on the screen in the GBA emu, this technique might be still useful.

It also used entirely the 8086 instruction set because it was coded
in A86, so it had no 32 bit instructions :) Now now, who was it
added the comment "Look ! A 32 bit instruction" to the code .....

 

That would be me.  And as I recall, I was quite pleased about it at the time.  ;-)

 

John