Tag: performance

The SNES core was losing four million cycles a frame waiting for a sound chip on another board to answer a one-byte question. Teaching the H7 to predict the answer and execute speculatively lifted dense Super Mario World from 35 to 49-52 fps. Then the fastest exact build ever measured painted garbage on the top of the screen while every checksum said it was perfect.

I spent days optimising the HDMI coprocessor because every symptom said it was holding the SNES back. The optimisations worked, the frame rate climbed, and then the measurements turned around and convicted a different part entirely: the wire. This is the story of proving a bottleneck before building its replacement.

The from-scratch SNES core matched the reference emulator to the cycle across a 750-frame run of Super Mario World. Then the hardware priced five optimisations: two worked, two did nothing, and a profiler said the real problem is memory, not arithmetic.

Cattle Crisis opened its first level at 9 FPS on the H753. One day of hardware A/Bs later it holds 58, Dank Tomb stopped dying of OOM, and the biggest single win was a compiler flag I should have set weeks ago.