Memory access improvement

semiversus / jeg

NES emulator with focus at hardware abstraction, testability and performance

MIT License

9 stars 2 forks source link

Memory access improvement #3

Closed GorgonMeducer closed 6 years ago

GorgonMeducer commented 6 years ago

Re-factory memory access to improve performance
improve readability
use uint_fastx_t to replace the original native data type. Balancing between portability and performance. NOTE: The re-factory doesn't change the original logic. The code has been verified.

semiversus commented 6 years ago

Closing this pull request - merged most of it, but some things are special:

Removed 16bit interface
Removed special DMA handling (it's really seldom used in games)
Didn't merged the interface for drawing pixels (but will come in future)
Had to make adaptations to pass all the test roms

Overall it improved the benchmark (running 1000 frames) by 2.7%. More to come...

GorgonMeducer commented 6 years ago

Thanks! Just one thing, could I add macros to make the 16bit read interface and dedicated dma interface an optimisation option? I do see the improvements on my poor cortex-m platform. due to the very limited computing power, I have to do the cycle level optimisation.

GorgonMeducer commented 6 years ago

I am doing next around update and will send a pull request again:

Adding macros to enable/disable optimisation options
using the latest ppu_upate

Cheers, Gabriel

semiversus commented 6 years ago

Could you keep the pull request rather small - going optimisation by optimisation? It's easier for me to understand and merge it and we can discuss the pull requests separately.

GorgonMeducer commented 6 years ago

I am very sorry about this. I will do it step by step in the future.