6502 Interactive Assembler

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This is a 65C02 assembler that assembles and simulates your program in real time as you type. It's useful for testing out instructions and short routines to observe their effects rather than for writing whole programs.

The original curses-based Python version (GitHub) runs here in the browser thanks to Brython.

Instruction references

Original 6502 instruction reference
Expanded 65C02 instruction reference