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20 lines
892 B
Markdown
20 lines
892 B
Markdown
# 6502-opcodes
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## Addressing modes
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* Immediate: a value literal
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* ZeroPage: argument is an 8-bit address to the zero page
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* ZeroPageX: argument is an 8-bit address to the zero page, incremented by X without carry
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* ZeroPageY: argument is an 8-bit address to the zero page, incremented by Y without carry
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* Absolute: argument is an 16-bit address
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* AbsoluteX: argument is an 16-bit address, incremented by X with carry
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* AbsoluteY: argument is an 16-bit address, incremented by Y with carry
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* Indirect: argument an address (A); the effective value is an address (B) stored at that address (A); used only by Jump
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* IndirectX: argument is an 8-bit address; find a value at this address incremented by the value X
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* IndirectY: argument is an 8-bit address; find a value at this address; increment the value by Y
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## TODO
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- add mapping support
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- postfix operations to accumulator values
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- loops |