Implement unused RDRAM address range 0x0800000-0x03EFFFFF

[Rosalie241]

Fixes an in-game crash in Paper Mario when hitting a specific tree with a hammer.

You can reproduce it with this save state (just hit B on the tree):

paper_mario_crash.zip

on the N64, 0x0800000-0x03EFFFFF are mapped, but reads/writes are ignored, see the n64brew documentation: https://n64brew.dev/wiki/RDRAM_Interface#Memory_addressing

[loganmc10]

I think this is correct, just a couple of notes:

Since you are directing everything to the RDRAM functions, I would just modify the existing line (replace dram_size-1):

{ A(MM_RDRAM_DRAM, 0x3efffff), M64P_MEM_RDRAM, { &dev->rdram, RW(rdram_dram) } },

In the functions themselves, I believe this:

if (address <= rdram->dram_size)

should be:

if (address < rdram->dram_size)

For example, if rdram->dram_size is 0x8000, then the RDRAM is 0x0 to 0x8000-1, 0x8000 would represent an address outside the valid RDRAM

[Rosalie241]

Yeah I wasn't entirely sure about the <= or < but upon looking at the code again, what you're saying seems right.

Thank you for your feedback, pushed it!

[loganmc10]

LGTM

[Narann]

Thanks for your work!