Do all true NROM/mapper 0 boards have only readonly CHR? If so, then presumably the instr_test-v3 tests won't work on a real NES.
How do I address this in my emulator if I want both the tests and 1942 to render properly? Which of the following options is best?
- If certainly NROM boards are write-able, somehow detect what board a given ROM represents and enable writes for those cases.
- Set CHR to be readonly for mapper 0 and introduce a hack to make it writeable for test ROMs only.
- Use only NES2.0 ROMs such that CHR RAM is made explicit? (An incomplete option since other emulators make do with just iNES.)
- Create a database of mapper 0 ROMs that tells my emulator which ROMs have writeable CHR. Or use someone else's existing database.
- Something else?
Thoughts? Thanks!