pub fn start_project_triple(
v0: Vec3I16,
v1: Vec3I16,
v2: Vec3I16,
) -> ProjectTripleInFlightExpand description
Load V0..V2 and issue RTPT without reading results, so the caller can overlap the GTE op with scalar work for the previous triple.
The MTC2 order matches project_triangle_scheduled: V0 is
written 6 instructions before RTPT issues and RTPT consumes V2
last, so the HWB-010/011 commit-slip hazard profile is unchanged.