Hallo Justin, > ... to use the REU to DMA things in and out of system RAM. That is one of my ideas well but how to use it exactly, that is something I have to figure out yet. I managed to start up from the Kernal ROM without the need of the BASIC ROM. Result: 51200 bytes free. The last time I used a REU is maybe 15 years ago. So I have to figure out how to use it again. Including how big the swap area can be. If it is more than 4 KB, then I'm happy that I swapped the BASIC ROM for RAM. I haven't been thinking about using the BASIC ROM range for an own one. I consider it a bit of an handicap that it is in "the middle" of the RAM. But it has one big advantage: immediately available and fast. > ... to use ... zero page ... That is what I am working on now: to free all zero page variables not needed by my ROM. Not only the zero page but also the RAM in the $02xx and $03xx range. That is not so difficult: just look if a variabele is used in the rest of the source code. If not, then just remove it from the source code as well. But I'm already running into a dilemma: what to do with all the gaps between the variables? A logical thought is to shift them all on one heap and creating one big free block of RAM for future use. The disadvantage: discompatibility. But if I start to loose compatibility, unfortunate but not something to shed tears about. To be continued.... -- Kind regards / Met vriendelijke groet, Ruud Baltissen www.Baltissen.orgReceived on 2026-05-20 19:00:01
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