Optimizing a 6502 image decoder – part II: assembly
16 hours ago
- #assembly
- #6502
- #optimization
- Optimizing for speed on a 1MHz 8-bit processor involves various tricks, including predictive branching, lookup tables, and self-modifying code.
- Aligning buffers to avoid page-crossing penalties and sticking to 8-bit operations can significantly improve performance.
- Avoiding stack function parameters and inlining operations reduces overhead and speeds up execution.
- Lookup tables are used to replace slow operations like shifting, providing faster alternatives.
- Self-patching code and branch prediction techniques help in optimizing frequently used code paths.
- Splitting 16-bit buffers into separate low and high byte arrays simplifies access and improves efficiency.
- Hardcoding pointers and approximating calculations can save cycles, especially in tight loops.
- Analyzing data patterns allows for special-case optimizations, such as handling common values more efficiently.
- Avoiding unnecessary checks and leveraging hardware limitations can further optimize performance.
- The article concludes with reflections on the optimization process and potential areas for further improvement.