Comment by corysama
3 years ago
A very old trick for running Lua in your PlayStation 2 game (where the PS2 is a machine with 32MB of RAM and no memory paging) is to hook Lua’s realloc function into the venerable Doug Lea’s Malloc (https://gee.cs.oswego.edu/dl/html/malloc.html) set up to run in arena mode (ONLY_MSPACES? It’s been a decade or two…). That way Lua can fragment the arena all it wants without making a mess of the rest of the tiny address space.
> (where the PS2 is a machine with 32MB of RAM and no memory paging)
The PS2 hardware does have full support for memory paging (at least on the main cpu core). PS2 Linux makes full use of it.
But the default TLB configuration from the BIOS is just a single static 31MB page (the other 1MB is reserved for the BIOS) and the SDK doesn't provide any tooling for dynamic pages.
And this is MIPS, so it's a software managed TLB with 48 entries. I wouldn't be surprised if some games did have dynamic paging, but they would need to provide their own TLB exception handler.
I recently needed to write a memory allocator and being lazy asked ChatGPT for help. Interestingly it came up with implementation eerily similar to what is described in that document. Nonetheless everything worked like a charm from the start.
Writing a memory allocator is a standard homework assignment in any CS program. The solutions are mostly similar, and ChatGPT has probably learned hundreds of examples.