Saturday, September 29, 2007

Current Game Display Part II

As you can see I got the current game display showing cards!

The problem was actually quite big. Up to this point the screens I had been viewing only used graphic characters found in the roms at locations between 0x00 and 0xFF. The card graphics are located beyond the 8-bit boundary of 0xFF and needed a 16-bit address in order to find them.

I found that the Port 1 actually stores the upper address I needed. It also stores the palette number. Up to this point, the palette had alway been zero, but once I got the value from P1 I had all I needed to display characters in higher addresses.

Another problem is the 8052 driver didn't seem to have a way for me to fetch the value of P1, so I had to add a new function to allow me access to internal ram values. Yet another change to the 8052 core that I will need to go back and document.

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