_flint_mpn_mulhigh_known_low
#include <flint/mpn_extras.h>void _flint_mpn_mulhigh_known_low(mp_ptr out, mp_srcptr x, mp_size_t xn, mp_srcptr y, mp_size_t yn, mp_srcptr kl, mp_size_t kl_len, mp_size_t klo, mp_size_t khi, mp_ptr scratch)sourceSets (\mathit{out}, \mathit{khi} - \mathit{klo}) to the exact limbs [\mathit{klo}, \mathit{khi}) of the product xy, given that its low \mathit{klo} limbs are known and equal to (\mathit{kl}, \mathit{kl\_len}) (zero above kl_len). The window is computed from a windowed middle product starting three guard limbs below \mathit{klo}, whose deficit is less than B^2 units of its lowest limb, and the known low limbs tell which carry was lost. scratch must have room for \mathit{khi} limbs. This is used by Hensel division and the 2-adic square root, where the low part of a product is known in advance.
The FLINT team, “_flint_mpn_mulhigh_known_low (mpn_extras.h),” FLINT: Fast Library for Number Theory, documentation, version 3.7.0-dev, 2026. https://flintlib.org/doc/mpn_extras/_flint_mpn_mulhigh_known_low.html (generated 2026-10-20).
@misc{flint-doc-mpn-extras-flint-mpn-mulhigh-known-low,
author = {{The FLINT team}},
title = {{\_flint\_mpn\_mulhigh\_known\_low (mpn\_extras.h)}},
howpublished = {FLINT: Fast Library for Number Theory, documentation, version 3.7.0-dev},
year = {2026},
url = {https://flintlib.org/doc/mpn_extras/_flint_mpn_mulhigh_known_low.html},
note = {Generated 2026-10-20}
}