Killing 2 birds with 1 stone

[+grafixbmp]

I know there are tons of nifty little tricks out there, but out of all of them, I would like to know of thoes involving doubling up on a single byte. For example, storing to a color register only requires the last 7 bits leaving the first one open for other things especialy triggers. likewise, PF0 only needs the last 4 while the first 4 can do something else. And even some triggers are conveniently located in a byte where an already avaliable byte can trigger it properly without having to load anything fresh. What are some of your favorite/most used tricks in pulling double time?

Edited October 13, 2009 by grafixbmp

[ScumSoft]

Sounds like neat tricks, but I thought all TIA registers were write only.

Edited October 13, 2009 by ScumSoft

[tokumaru]

Sounds like neat tricks, but I thought all TIA registers were write only.

I believe he meant that when the data that will be written to the registers is stored in the ROM, the bits that are not used by the TIA can be used to store other information, not that you can use the TIA for extra memory.

[+batari]

Sounds like neat tricks, but I thought all TIA registers were write only.

No, the collision registers, joystick buttons and paddle registers may be read.

[ScumSoft]

Yes with the exception of those of course

 

I understand what is being said now, I thought you were somehow accessing the data written to the read only registers.

You wish for the lower nibble of PF0 to set a flag, then push that flag onto the stack in order for it to be reused later on correct?

[+grafixbmp]

Since the status flag register holds 7 diffrent status flags for varius things, are there several types of instances where many TIA registers align just right for current flags states to trigger TIA registers other than the missles?

 

Also, is it a common practice to keep a RAM reference of both NUSIZ since they control multiple things with graphics. Or even other TIA registers. Like when you need to make modifications to a specific part without changing the other sections. I wondered if the processor status could do some of these changes like with the missles.

Edited October 16, 2009 by grafixbmp