mpn_sec_div_r

[Torbjörn Granlund]

nisse at lysator.liu.se (Niels Möller) writes:

  And there's also a similar table lookup in binvert_limb, used by
  mpn_sec_powm.

I am surprised that I implemented it like that.  This needs fixing.

For binvert_limb, doing some logics should get us 4 bits, than just one
more iteration.  We could as well define a binvert_limb_sec or
sec_binvert_limb (in C).

For invert_limb, we should write some leak-free C code for generating a
suitable table, I suppose.  Unfortunately, not all asm invert_limb's are
the same, and need different tables.  So we cannot just drop inte them
from that C code.

Perhaps we should simply write a leakage free C invert_limb, and then
add faster entry points to the asm invert_limb as sec_invert_limb.  The
latter is no hurry.

-- 
Torbjörn
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