From: eb Date: Fri, 15 Aug 2008 01:12:02 +0000 (+0000) Subject: Trial fix for ticket:258 / integer overflow undefined / phase X-Git-Url: https://git.gag.com/?a=commitdiff_plain;h=f806d765aab07876d073b60ad3cc5d3df321b87f;p=debian%2Fgnuradio Trial fix for ticket:258 / integer overflow undefined / phase accumulator. Thanks to Stefan Bruens and Philip Ballister for working on this. According to the fine print in the C and C++ standards, if a signed integer type overflows, the result is undefined. As of gcc 4.3, gcc was proving that our code was overflowing, and took advantage of the "undefined" result to short circuit the evaluation. Moral of the story: if you're using a fixed point phase accumulator, or anything else where you're counting on overflow happening, be sure that your variable is unsigned. See also http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37067 and http://www.airs.com/blog/archives/120 git-svn-id: http://gnuradio.org/svn/gnuradio/trunk@9296 221aa14e-8319-0410-a670-987f0aec2ac5 --- diff --git a/gnuradio-core/src/lib/general/gr_fxpt_nco.h b/gnuradio-core/src/lib/general/gr_fxpt_nco.h index 6487a5f4..ca0d54f0 100644 --- a/gnuradio-core/src/lib/general/gr_fxpt_nco.h +++ b/gnuradio-core/src/lib/general/gr_fxpt_nco.h @@ -30,7 +30,7 @@ * \ingroup misc */ class gr_fxpt_nco { - gr_int32 d_phase; + gr_uint32 d_phase; gr_int32 d_phase_inc; public: