3 ms·
> the SNES PPU's default-on-boot graphics mode is compatible with drawing NES-PPU-formatted CHR-ROM data; SNES 2bpp tile format is actually identical to the Ga
by benchloftbrunch 2y ago
> the SNES PPU's default-on-boot graphics mode is compatible with drawing NES-PPU-formatted CHR-ROM data;
SNES 2bpp tile format is actually identical to the Game Boy's format; iirc the difference from NES is that the bitplanes are interleaved instead of separate.
> But is the SNES's (variant) 65C816 ISA a strict superset of the NES's (variant) 6502 ISA?
Mostly yes, the biggest exception being the infamous illegal opcodes which a few NES games did use. The other being that decimal mode actually works.
The main challenge in porting a game from NES to SNES would have been with the wildly different PPU and audio systems.
> it would be theoretically possible to write a NES-to-SNES static transpiler.
For simple games, static translation might be possible, but later era NES games' widespread use of cycle-timed raster effects and bank switching mappers makes it more complicated. (You could theoretically put such a mapper in an SNES cart too, but nobody did that.)