Posted By
gerliczer
on 2015-02-22
17:56:49
|  Re: Bankswitching of Plussy and its programming
Mysterious. Maybe you should try it without using the system reserved memory space by changing the zero page indirect indexed read into a simple absolute address read using self modifying code. Actually, the addresses $07f2-$07f5 can be used to set the CPU register values when calling a machine code subroutine with SYS, so there is no need to use the tape buffer for passing the requested memory address. And, according to the Ultimate Map, it also can be used to read the register values after exiting the routine, so you could omit completely the use of system reserved memory.
Now, some unrelated remarks. There is no need to write zero into $ff3e or $ff3f, because only the fact of write access counts not the written data content. There is no actual use of the zero value in the accumulator in your code, therefore you may omit this zeroing. The origin in your code example has a typo, it should be $4a38. The explanation too, because it refers to the 1000, 1000 addresses but the second should be 1001. These typos scared me a bit when reading your post, because I thought I misunderstood what you were trying to explain.
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