diff options
Diffstat (limited to 'numeric.c')
| -rw-r--r-- | numeric.c | 35 |
1 files changed, 35 insertions, 0 deletions
@@ -629,6 +629,41 @@ Perl_nan_signaling_set(NV *nvp, bool signaling) } /* +=for apidoc nan_is_signaling + +Returns true if the nv is a NaN is a signaling NaN. + +=cut +*/ +int +Perl_nan_is_signaling(NV nv) +{ + /* Quiet NaN bit pattern (64-bit doubles, ignore endianness): + * x86 00 00 00 00 00 00 f8 7f + * sparc 7f ff ff ff ff ff ff ff + * mips 7f f7 ff ff ff ff ff ff + * hppa 7f f4 00 00 00 00 00 00 + * The "7ff" is the exponent. The most significant bit of the NaN + * (note: here, not the most significant bit of the byte) is of + * interest: in the x86 style (also in sparc) the bit on means + * 'quiet', in the mips style the bit off means 'quiet'. */ +#ifdef Perl_fp_classify_snan + return Perl_fp_classify_snan(nv); +#else + if (Perl_isnan(nv)) { + U8 mask; + U8 *hibyte = Perl_nan_hibyte(&nv, &mask); + /* Hoping NV_NAN is a quiet nan - this might be a false hope. + * XXX Configure test */ + const NV nan = NV_NAN; + return (*hibyte & mask) != (((U8*)&nan)[hibyte - (U8*)&nv] & mask); + } else { + return 0; + } +#endif +} + +/* =for apidoc grok_infnan Helper for grok_number(), accepts various ways of spelling "infinity" |