Just for fun. This is 95% based off https://www.youtube.com/watch?v=8XmxKPJDGU0 No original thought from me :L)
The nestest completes (https://github.com/christopherpow/nes-test-roms/blob/master/other/nestest.nes) as in all operations in the correct order are executed. Checks for the registers/flags not performed yet (but the fact the ops complete is a good indication)
16 bit address bus 8 bit data bus
Registers
A: Accumulator X: Register Y: Register (above 3 are 8 bit)
stkp: Stack pointer : 8 bit points to memory location pc: Program counter : 16 bit. Address of next byte to read for program status: status register : (last operation resulted in zero, disable interrupts etc. Each of these flags is a single bit)
For comparison instructions, the results are usually found in flags: Compare Result N Z C A, X, or Y < Memory * 0 0 A, X, or Y = Memory 0 1 1 A, X, or Y > Memory * 0 1
https://www.youtube.com/watch?v=8XmxKPJDGU0 https://www.masswerk.at/6502/6502_instruction_set.html