I discovered a few differences in the gcc implemenation of the <float.h> macros, as compared with the ISO C Tr24732 paper. It may be more likely that the gcc implementation is incorrect.
In any case, here's what I see in the decfloat-constants.c test from the gcc 4.3 testsuite: if (DEC32_MIN_EXP != -95) abort(); if (DEC64_MIN_EXP != -383) abort(); if (DEC128_MIN_EXP != -6143) abort(); if (DEC32_MAX_EXP != 96) abort(); if (DEC64_MAX_EXP != 384) abort(); if (DEC128_MAX_EXP != 6144) abort(); Here's the info from Tr24732: - minimum exponent DEC32_MIN_EXP -94 DEC64_MIN_EXP -382 DEC128_MIN_EXP -6142 - maximum exponent DEC32_MAX_EXP 97 DEC64_MAX_EXP 385 DEC128_MAX_EXP 6145 As you can see, they appear to be off-by-one (gcc is always one less). The constants are generated by the gcc compiler (at least gcc 4.3.0 20071012, which I am using), so the decfloat-constants test passes. Also, gcc sets DEC32_DEN, etc: if (DEC32_DEN != 0.000001E-95DF) abort(); if (DEC64_DEN != 0.000000000000001E-383DD) abort(); if (DEC128_DEN != 0.000000000000000000000000000000001E-6143DL) abort(); Tr24732 specifies these as DEC32_SUBNORMAL_MIN, etc: DEC32_SUBNORMAL_MIN 0.000001E-95DF DEC62_SUBNORMAL_MIN 0.000000000000001E-383DD DEC128_SUBNORMAL_MIN 0.000000000000000000000000000000001E-6143DL See http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1241.pdf It looks like the gcc values came from the <decfloats.h> implementation and not TR 24732. -- Summary: DEC32_MIN_EXP, DEC32_MAX_EXP don't match TR 24732 Product: gcc Version: 4.3.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: jeff dot sullivan at intel dot com http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34252
