EVSM warp exponent for fp16 moment storage. Capped so the warped second
moment exp(2c) stays inside FP16_MAX: exp(2·5.5) ≈ 59874 < 65504.
This is a weak warp — fp16 EVSM is markedly less effective than fp32 — so
prefer plain VSM + bleed reduction when only fp16 is available.
EVSM warp exponent for fp16 moment storage. Capped so the warped second moment
exp(2c)stays inside FP16_MAX:exp(2·5.5)≈ 59874 < 65504. This is a weak warp — fp16 EVSM is markedly less effective than fp32 — so prefer plain VSM + bleed reduction when only fp16 is available.