2020-08-12 03:04:23 +00:00
|
|
|
# 6502-opcodes
|
|
|
|
|
|
|
|
## Addressing modes
|
|
|
|
|
|
|
|
* Immediate: a value literal
|
|
|
|
* ZeroPage: argument is an 8-bit address to the zero page
|
|
|
|
* ZeroPageX: argument is an 8-bit address to the zero page, incremented by X without carry
|
|
|
|
* ZeroPageY: argument is an 8-bit address to the zero page, incremented by Y without carry
|
|
|
|
* Absolute: argument is an 16-bit address
|
|
|
|
* AbsoluteX: argument is an 16-bit address, incremented by X with carry
|
|
|
|
* AbsoluteY: argument is an 16-bit address, incremented by Y with carry
|
|
|
|
* Indirect: argument an address (A); the effective value is an address (B) stored at that address (A); used only by Jump
|
|
|
|
* IndirectX: argument is an 8-bit address; find a value at this address incremented by the value X
|
2020-08-15 17:52:05 +00:00
|
|
|
* IndirectY: argument is an 8-bit address; find a value at this address; increment the value by Y
|
|
|
|
|
|
|
|
## TODO
|
|
|
|
|
2020-08-15 21:34:33 +00:00
|
|
|
- add mapping support
|
2020-08-15 17:52:05 +00:00
|
|
|
- postfix operations to accumulator values
|
|
|
|
- loops
|