ref: 8f63d48a00251d74b67e7244c908e436cb540d2c
dir: /sys/src/ape/lib/openssl/crypto/bn/bn.mul/
We need * bn_mul_comba8 * bn_mul_comba4 * bn_mul_normal * bn_mul_recursive * bn_sqr_comba8 * bn_sqr_comba4 bn_sqr_normal -> BN_sqr * bn_sqr_recursive * bn_mul_low_recursive * bn_mul_low_normal * bn_mul_high * bn_mul_part_recursive # symetric but not power of 2 bn_mul_asymetric_recursive # uneven, but do the chop up.