6502 instructions: Difference between revisions
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Below are some references for the 6502 instruction set: | Below are some references for the 6502 instruction set: | ||
* [[Instruction reference]], describing all official instructions and how they function | |||
* [[CPU unofficial opcodes]], including a full opcode matrix of all official and unofficial opcodes | * [[CPU unofficial opcodes]], including a full opcode matrix of all official and unofficial opcodes | ||
* [[Programming with unofficial opcodes]] | * [[Programming with unofficial opcodes]] | ||
* [[6502 assembly optimisations]] | * [[6502 assembly optimisations]] | ||
* [[Delay code]], how to create a delay of a precise number of CPU cycles with smallest number of code bytes | * [[Delay code]], and [[Fixed cycle delay]]: how to create a delay of a precise number of CPU cycles with smallest number of code bytes | ||
* [[6502 cycle times]] | |||
== External links == | == External links == | ||
* http://users.telenet.be/kim1-6502/6502/proman.html - MOS 6502 programming manual | * http://users.telenet.be/kim1-6502/6502/proman.html - MOS 6502 programming manual | ||
* http://nesdev.org/6502_cpu.txt - Includes tick-by-tick breakdowns of instructions (see [[CPU interrupts]] for breakdowns of interrupts) | * http://nesdev.org/6502_cpu.txt - Includes tick-by-tick breakdowns of instructions (see [[CPU interrupts]] for breakdowns of interrupts) | ||
* [http://visual6502.org/ Visual 6502] can be used to figure out obscure instruction behavior. There's also a [ | * https://www.nesdev.org/obelisk-6502-guide/reference.html - Historical 6502 instruction reference, but largely obsoleted by NESdev's [[instruction reference]] | ||
* [http://visual6502.org/ Visual 6502] can be used to figure out obscure instruction behavior. There's also a [https://www.qmtpro.com/~nes/chipimages/visual2a03/ 2A03 version] available (hosted on residential broadband, so avoid needless shift-reloading). There is also [[Visual_circuit_tutorial|a tutorial on reading the circuit diagrams]] available, aimed at beginners. | |||
Latest revision as of 10:41, 1 November 2024
Below are some references for the 6502 instruction set:
- Instruction reference, describing all official instructions and how they function
- CPU unofficial opcodes, including a full opcode matrix of all official and unofficial opcodes
- Programming with unofficial opcodes
- 6502 assembly optimisations
- Delay code, and Fixed cycle delay: how to create a delay of a precise number of CPU cycles with smallest number of code bytes
- 6502 cycle times
External links
- http://users.telenet.be/kim1-6502/6502/proman.html - MOS 6502 programming manual
- http://nesdev.org/6502_cpu.txt - Includes tick-by-tick breakdowns of instructions (see CPU interrupts for breakdowns of interrupts)
- https://www.nesdev.org/obelisk-6502-guide/reference.html - Historical 6502 instruction reference, but largely obsoleted by NESdev's instruction reference
- Visual 6502 can be used to figure out obscure instruction behavior. There's also a 2A03 version available (hosted on residential broadband, so avoid needless shift-reloading). There is also a tutorial on reading the circuit diagrams available, aimed at beginners.
