[StringyBob]

See also virtual 6502 and ARM1 e.g. http://www.visual6502.org/sim/varm/armgl.html

[Aissen]

You might also want floooh's remix which has a nicer UI, with the ability to see instructions evaluated, modify memory, assemble/disassemble code, view traces, etc.

Visual 6502 remix: https://floooh.github.io/visual6502remix/ Visual Z80 remix: https://floooh.github.io/visualz80remix/

[butlike]

This is going to sound quaint, but because of this simulation, this is the first time I realized they're _literal_ flags on the sides of the CPU, which is blowing my mind.

[epcoa]

You mean the pads? Those are the connection points for the wires that connect to the external package pins.