How do you set DMA and memorie and apply to game?

[dawei]

Hi there -- this is probably a very basic question, but I am new -- several games I'm trying to play use DMA -- how is this set and applied to the game? Also, how do you set the memory and apply tot he game. Thank you for you all your help -- specifically, Sonic Adventure uses DMA -- not sure how to apply and Crazy Taxi uses a memory address, but not sure where to apply.

Thank you!!