Use wider integers for shifts

[riscv-non-isa]

Use wider integers for shifts

[zakk0610]

Agree, spec already reserves SEW=1024 supported.

Unfortunately uintXLEN_t is still in the PR, riscv-non-isa/riscv-c-api-doc#14
Which type are you prefer to use? unsigned long?

[nick-knight]

I propose we just define uint_xlen_t in the usual way in the riscv_vector.h, and delete it when the C API PR is approved and added to compilers. Hopefully this can be done without breaking user code because riscv_vector.h is bundled with the toolchain.

I'm pretty sure the P-extension does the same thing in their intrinsics header file. I don't know about other extensions' intrinsics.

I'm not an expert on this kind of thing, happy to hear alternatives.

[kito-cheng]

I propose we just define uint_xlen_t in the usual way in the riscv_vector.h, and delete it when the C API PR is approved and added to compilers. Hopefully this can be done without breaking user code because riscv_vector.h is bundled with the toolchain.

That SGTM, I think intrinsic for B extension should need that too.

[zakk0610]

Before we have uint_xlen_t, could we use size_t type for shift amount ?

[nick-knight]

This was addressed by #72 , although I think this and related aspects of the API should be revisited once we have XLEN-width integer types to replace size_t, long, etc.