Nemu says DMULTU:
00000000000031E1 * FFFFFFFFFFFFFF1D = 000031E0FFD3C57D
but should equal:
FFFFFFFFFFD3C57D
In other words, Nemu handles DMULTU the same as MULTU!
Turns out the reason GoldenEye suffers those crazy blackout issues is due to an error in the way DMULTU is handled. It's being...