Re: extended ROM format

[Maarten ter Huurne]

On Monday 22 January 2001 11:38, you wrote:

> I'll study how the extended VRAM works :)

In VDP register 45, bit 6 specifies whether you want to access the normal 
VRAM or the expansion RAM.

The easiest way to access the extended VRAM is through port #98. You can also 
use VDP commands to access it, but there is no HMCM command, so you can only 
transfer from extended VRAM to CPU at the pixel level, not at the byte level. 
This is bad, because you have to know the screen mode. Also, in SCREEN5 it's 
twice as slow as transferring bytes.

Bye,
                Maarten

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