sprites and joypad next?
Over here I've improved behaviour of IRQ/BRK simultaneous with NMI and fixed a few undocumented opcodes, thanks to blargg's newest test ROMs. I think I'll add savestate/movie support next.
Nice fog in Super Mario Bros
I had a peek at your MMC1 code:
- reg 0 vertical/horizontal mirroring not implemented
- reg 3 prg bank is 4 bits, so AND with $F, not 7
- reg 3 32K switch mode lowest bit is ignored, so AND with $E
Do nestest.nes and blargg's CPU opcode test pass?