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| author | Marco Bodrato <bodrato@mail.dm.unipi.it> | 2020-02-02 16:05:45 +0100 |
|---|---|---|
| committer | Marco Bodrato <bodrato@mail.dm.unipi.it> | 2020-02-02 16:05:45 +0100 |
| commit | 0e300e7843e1633eaa3aebd3e5577fdb8fa3cee4 (patch) | |
| tree | 82edb78366821c025b48dd0d205825be51ae14c2 /mpn | |
| parent | ee06fcde206905dda7ac5657c504676cc656fa17 (diff) | |
| download | gmp-0e300e7843e1633eaa3aebd3e5577fdb8fa3cee4.tar.gz | |
mpn/generic/powm.c: Better handling of current window-size.
Diffstat (limited to 'mpn')
| -rw-r--r-- | mpn/generic/powm.c | 21 |
1 files changed, 6 insertions, 15 deletions
diff --git a/mpn/generic/powm.c b/mpn/generic/powm.c index 1a3e83d7d..201f17d2b 100644 --- a/mpn/generic/powm.c +++ b/mpn/generic/powm.c @@ -6,7 +6,7 @@ SAFE TO REACH THEM THROUGH DOCUMENTED INTERFACES. IN FACT, IT IS ALMOST GUARANTEED THAT THEY WILL CHANGE OR DISAPPEAR IN A FUTURE GNU MP RELEASE. -Copyright 2007-2012, 2019 Free Software Foundation, Inc. +Copyright 2007-2012, 2019, 2020 Free Software Foundation, Inc. This file is part of the GNU MP Library. @@ -142,7 +142,7 @@ getbits (const mp_limb_t *p, mp_bitcnt_t bi, int nbits) mp_limb_t r; mp_size_t i; - if (bi < nbits) + if (bi <= nbits) { return p[0] & (((mp_limb_t) 1 << bi) - 1); } @@ -682,11 +682,9 @@ mpn_powm (mp_ptr rp, mp_srcptr bp, mp_size_t bn, } expbits = getbits (ep, ebi, windowsize); - if (ebi < windowsize) - ebi = 0; - else - ebi -= windowsize; + ebi -= windowsize; + /* THINK: Should we initialise the case expbits % 4 == 0 with a mul? */ count_trailing_zeros (cnt, expbits); ebi += cnt; expbits >>= cnt; @@ -709,18 +707,11 @@ mpn_powm (mp_ptr rp, mp_srcptr bp, mp_size_t bn, significant bit is 1. */ \ \ expbits = getbits (ep, ebi, windowsize); \ - this_windowsize = windowsize; \ - if (ebi < windowsize) \ - { \ - this_windowsize -= windowsize - ebi; \ - ebi = 0; \ - } \ - else \ - ebi -= windowsize; \ + this_windowsize = MIN (ebi, windowsize); \ \ count_trailing_zeros (cnt, expbits); \ this_windowsize -= cnt; \ - ebi += cnt; \ + ebi -= this_windowsize; \ expbits >>= cnt; \ \ do \ |