[libre-riscv-dev] Vector Operations Extension (cross, dot, length, lerp, slerp)

lkcl luke.leighton at gmail.com
Sat Oct 5 10:39:14 BST 2019

(Tracking this extension here)

Found a paper which describes vector normalisation in terms of dotproduct, 
scalar recipsqrt and then scalar-vector fmul.

With VLENGTH being also expressible as dotproduct followed by scalar sqrt, 
is it reasonable to have both normalisation as well as VLENGTH as macro op 
fused sequences?

Or, are they sufficiently common that there is significant overhead in 
loops, particularly from the vector-scalar context setup, that both or 
either warrant their own opcode (done most likely as microcode)?


More information about the libre-riscv-dev mailing list