6502 Debugger
Write 6502 assembly in the browser and watch it execute live. Full two-pass assembler, all 56 opcodes, step-by-step execution, live register and flag display, and a hex memory inspector. C64 / 6510 compatible.
Open Debugger
Opens full-screen in a new tab.
Assembler Two-pass assembler. All 56 opcodes, all 13 addressing modes, labels, .ORG, .BYTE.
Step / Run Step one instruction at a time or run continuously. Speed slider from 1 Hz to ~600k/s.
Registers Live A, X, Y, PC, SP display. All eight status flags (N V ‒ B D I Z C) highlighted on change.
Memory Scrollable hex dump of all 64KB. Current instruction highlighted in amber. Jump to PC.
Stack Live view of $0100–$01FF stack area. SP pointer shown at current top.
6510 Compatible Standard 6502 instruction set. Includes the indirect JMP page-boundary bug for accuracy.