implements the entire official instruction set
assembler used: http://sun.hasenbraten.de/vasm/
compiled with CPU=6502 SYNTAX=oldstyle
reference:
- https://pl.wikipedia.org/wiki/MOS_Technology_6502
- http://www.emulator101.com/6502-addressing-modes.html
- https://www.youtube.com/watch?v=8XmxKPJDGU0
- https://en.wikibooks.org/wiki/6502_Assembly
- https://www.masswerk.at/6502/6502_instruction_set.html#PHP
- http://www.oxyron.de/html/opcodes02.html
- https://www.youtube.com/watch?v=oO8_2JJV0B4