I've uploaded a fix for an ECM bug.  If you run ECM on a P4 you should
upgrade to 22.13.  All other users can continue to use 22.12.

V22.13 is at ftp://mersenne.org/gimps/p95v2213.zip
and ftp://mersenne.org/gimps/p95v2213.exe

The ECM bug only occurred for exponents below 172,000 and near an
FFT crossover point.  It did not affect any Fermat factoring.  Most
Cunnningham factoring was unaffected because the FFT crossovers are
at 743 and 1473.  If you want to determine if some of your past ECM runs
on a  P4 were affected, then in v22.12 turn on round-off checking, and
run an ECM curve on the exponent with B1=100.  If the round-off error
is 0.5 then your past ECM runs were affected by the bug.

The good news is v22.13 does have a P-1 and ECM QA suite implemented.
There is a pretty good chance that the last serious bug in this area of the
program has been found.  I've run a small QA file successfully.  Over time
the QA volunteers will undoubtedly improve the QA suite.

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