Make DATA0 and DATA1 available as zero page addresses (25% faster VERA data transfer)

[Jeffrey]

Hi,

Right now sending bytes to VERA takes 4 cycles, like this:

STA $9F23

As far as I know there is no faster way to send data to VERA right now.

But if you could make DATA0 (and DATA1) available as zero page addresses you would make sending data to VERA 25% faster, like this (the address $70 is just an example) :

STA $70

That would take only 3 cycles.

This is especially noticable when drawing many pixels of the same colour (for example textureless polygons for 3D rendering). 

I dont know exactly what it would take from a hardware perspective, probably some logic to select/enable the VERA data port based on the specific address bus lines. If its not too hard it would likely pay off quite significantly.

Regards,

Jeffrey

 

 

[Lorin Millsap]

This has already been brought up, and the technical reasons why it can’t be done have been throughly broken down. This isn’t going to happen and the design is set.


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