How to get vector lane / number of lanes from within loop

Question

mppf opened this issue 4 years ago · comments

Suppose I am using RV to expose a SIMT programming model.

How can I arrange for the generated code to get the current vector lane as well as the number of vector lanes used from within a vectorized loop?

Thanks.

Simon Moll · Answer 1 · Mon Sep 28 2020 16:39:07 GMT+0800 (China Standard Time)

There is currently no way to query this from the SIMT code itself. I will add two new intrinsics:

i32 rv_lane() that returns the vector lane id.
i32 rv_num_lanes() that returns the number of lanes.

Michael Ferguson · Answer 2 · Mon Sep 28 2020 21:34:57 GMT+0800 (China Standard Time)

@simoll - thanks!

Simon Moll · Answer 3 · Thu Oct 01 2020 00:10:53 GMT+0800 (China Standard Time)

Implemented by 92b679a

The intrinsics are called:

rv_lane_id()
rv_num_lanes()