- Implement s_mp_mul_2d, which complements s_mp_div_2d. - Rewrite and speed up mp_sqr, most-frequently used in mp_exptmod(). - Speed up mp_sqrt by starting with a much better initial estimate.
- Implement s_mp_mul_2d, which complements s_mp_div_2d.
- Rewrite and speed up mp_sqr, most-frequently used in mp_exptmod().
- Speed up mp_sqrt by starting with a much better initial estimate.

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