Incompatibility of simulator and microprocessors 6502 and 65C02
Compared to 6502 and 65C02 microprocessors, the simulator is characterized by the following different components:
- There is no relationship between the speed of different opcodes.
- Illegal codes in 6502 mode are not executed, but cause the program to stop.
- Illegal codes in 65C02 mode are treated as NOP statements and do not cause the program to stop.
- BRK, RTS, and $DB are privileged because one of them, depending on the settings, ends the program.
- Reserved bits in the Status register (P) are always set to 1 (as in 65C02, but not in 6502).