pbrt on 32-bit archs

[jonahbeckford]

In pbrt.3.0.1 the 32-bit architectures were dropped. 6462948

The pbrt runtime seems very light. What was the reason for it being dropped? Is it something that help is needed with?

Thanks!

[c-cube]

It's possible to adapt the code for 32 bits, I think, on paper. The issue is that there are C stubs which assume 64 bits integers (they could return int64 anyway but this might hurt performance?).

Do you use a 32 bits architecture that's not js?

[jonahbeckford]

The issue is that there are C stubs which assume 64 bits integers (they could return int64 anyway but this might hurt performance?).

Okay. I may supply a patch that has specialized stubs only for 32-bit so that 64-bit performance is not impacted. (My mitigation is to use pbrt 3.0.0 for now, so this isn't urgent).

Do you use a 32 bits architecture that's not js?

Yes; android_arm32v7a. (And windows_x86 but that is an edge case that is growing less important: to simplify instructions to run a standalone OCaml binary on Windows.)

This also affects js and wasm, right? Or is the assumption that JS/WASM will be compiled on 64-bit machines and always downshift gracefully to 32 bits? Confer https://discuss.ocaml.org/t/a-hybrid-32-bit-64-bit-abi-bx32-to-avoid-input-value-integer-too-large/16995.

[c-cube]

Ok, a patch with a 32 bit version would be good to have!

For js one would have to provide .js stubs anyway. For wasm I honestly don't know, the stubs would need to be compiled to wasm somehow?? I profess my ignorance there.