try using the 4.6.3 compiler. 3.2.3 is really old. It isn't clear what level of support for floating point exists. Peter (the current msp430 gcc maintainer) will have more information.
But do try 4.6.3 first. You can get it in the msp430-46 package at http://tinyprod.net/repos/debian/README-46.html Thanks for taking the time to look at this. On Tue, Sep 18, 2012 at 12:13 PM, Flemming Nyboe <flemm...@rocketscience.eu>wrote: > Hello, > > On the MSP430, all floating points types are 32 bit. > A cast from int64_t to float produces strange results: > Negative values are rounded to multiples of -256 (tested for -10000 to 0) > Positive numbers smaller than 8725651e09 (8.7e15) are converted correctly, > tested at 0.1% intervals. Above this number, it sometimes, but not always, > goes wrong by many orders of magnitude. Example: > 8725651e09 casts to 8725651e09 (OK) > 8725738e09 casts to 837068800 (extremely wrong) > Some larger values still cast correctly. > > According to standard, the cast is legal, right? 32-bit float does cover > the range of int64_t, although with some inaccuracy for large values. Or > would this have been fixed in a later msp430-gcc? > > As has been pointed out before > > https://www.millennium.berkeley.edu/pipermail/tinyos-help/2010-November/048878.html > FTSP TimeSyncP.nc calculateConversion() uses this cast, and it results in > wrong skew values if the points in the timesync table are spaced enough for > int64_t localSum to reach the faulty range. > > Setup > msp430tools-gcc-3.2.3-20050607 > nescc: 1.3.4 > > Best Regards > Flemming Nyboe > www.rocketscience.eu > > > _______________________________________________ > Tinyos-help mailing list > Tinyos-help@millennium.berkeley.edu > https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help > -- Eric B. Decker Senior (over 50 :-) Researcher
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