Tag: emulation

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.

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.

The emulated Amiga gets a mouse, opens a window, and then boots Turrican II - whose custom trackloader refused to work until the floppy drive learned to actually spin.

One evening after the 68000 passed its cycle budget, the emulated Amiga boots a real Workbench 1.3 floppy to the desktop. The chipset, the floppy, and the three bugs that stood between a spinning motor and the blue screen.

First hardware numbers for the Amiga 500 programme: a real Kickstart 1.3 ROM executing deterministically on the STM32H753, with a p99 of 2.51M cycles per PAL frame against a 3.35M gate.

I put a Mega Drive emulator on a 480MHz Cortex-M7, carried its video over an 8MHz jumper-wire link, and got perfect music beside a screen that tore in half. The fix was to make a slow frame arrive atomically.

Two days from a feasibility study to DMG code rendering pixel-perfect on the TV: picking an emulator core, passing Blargg and dmg-acid2 on the host, and teaching the console's SPI video wire to carry two frame geometries at once.