Changes

MOS 6502

90 bytes added, 27 April
/* The Decode ROM (PLA) */
For a specific example, the 6502 PLA decodes instructions matching 100XX1XX to the control line STY (ignoring the timing bits for simplicity). This takes 1 row in the PLA, but it would take 16 entries in a ROM. [https://news.ycombinator.com/item?id=13128074 Source]
See: [https://web.archive.org/web/20210519010632/http://visual6502.org/wiki/index.php?title=6507_Decode_ROM 6507 Decode ROM (PLA)] [https://pastraiser.com/cpu/65CE02/65CE02_rom.html 65CE02 Decode ROM (PLA)] [https://www.righto.com/2016/02/reverse-engineering-arm1-instruction.html ARM1, Z80, 6502 instruction sequencing compared] [https://www.pagetable.com/?p=410 Internals of BRK/IRQ/NMI/RESET on a MOS 6502] [https://www.pagetable.com/?p=39 How MOS 6502 illegal opcodes really work] [https://c74project.com/wp-content/uploads/2020/04/c74-6502-microcode.pdf 6502 microcode]
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