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Z65C02 processor core
To maximize the performance of my Soft 6502 Second Processor I developed my own 65C02 core.
Mainly by abusing surplus FPGA block RAM, instruction cycle counts are drastically reduced. The result is a core that needs a ridiculous amount of extra RAM, but roughly doubles the number of instructions per cycle.
There are three slightly different versions. The 'full' one requires roughly 448 KB of (dual-ported) RAM. The 'small' one drops that to 256 KB, but slows down all absolute addressed instructions by one cycle. The 'tiny' one drops that once more to only 64 KB, but slows down JSR and exceptions by one cycle.
For some notes on the development of this core, visit the 6502.org forum here.
View the sources below or download them here, and note the comments at the tops.
First published 14 January 2022.
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