On Mon, 16 May 2016, Aleksandar Markovic wrote: > Here one can distinguish three cases: > > CASE MIPS-A: (FCR31.NAN2008 == 1) > > 1. Operand is a NaN, result should be 0; > 2. Operand is larger than INT_MAX, result should be INT_MAX; > 2. Operand is smaller than INT_MIN, result should be INT_MIN. > > CASE MIPS-B: (FCR31.NAN2008 == 0) > > 1. Operand is a NaN, result should be INT_MAX; > 2. Operand is larger than INT_MAX, result should be INT_MAX; > 2. Operand is smaller than INT_MIN, result should be INT_MAX. > > CASE SOFTFLOAT: > > 1. Operand is a NaN, result is INT_MAX; > 2. Operand is larger than INT_MAX, result is INT_MAX; > 2. Operand is smaller than INT_MIN, result is INT_MIN. > > It is interesting that neither MIPS-A nor MIPS-B desired behaviors > are in this sense identical to correspondent SoftFloat behavior.
A bug in SoftFloat probably -- it has only been fixed quite recently to handle all MIPS architecture's peculiarites correctly and this case must have been missed then, making data produced not necessarily identical between the legacy-NaN hard-float and the soft-float ABIs, even though intent has been for it to be. FAOD, you refer to SoftFloat in the most recent version of GCC, do you? Maciej
