diff options
Diffstat (limited to 'numeric.c')
| -rw-r--r-- | numeric.c | 35 |
1 files changed, 35 insertions, 0 deletions
@@ -548,6 +548,41 @@ Perl_grok_numeric_radix(pTHX_ const char **sp, const char *send) } /* +=for apidoc nan_hibyte + +Given an NV, returns pointer to the byte containing the most +significant bit of the NaN, this bit is most commonly the +quiet/signaling bit of the NaN. The mask will contain a mask +appropriate for manipulating the most significant bit. +Note that this bit may not be the highest bit of the byte. + +If the NV is not a NaN, returns NULL. + +Most platforms have "high bit is one" -> quiet nan. +The known opposite exceptions are older MIPS and HPPA platforms. + +Some platforms do not differentiate between quiet and signaling NaNs. + +=cut +*/ +U8* +Perl_nan_hibyte(NV *nvp, U8* mask) +{ + STRLEN i = (NV_MANT_REAL_DIG - 1) / 8; + STRLEN j = (NV_MANT_REAL_DIG - 1) % 8; + + PERL_ARGS_ASSERT_NAN_HIBYTE; + + *mask = 1 << j; +#ifdef NV_BIG_ENDIAN + return (U8*) nvp + NVSIZE - 1 - i; +#endif +#ifdef NV_LITTLE_ENDIAN + return (U8*) nvp + i; +#endif +} + +/* =for apidoc grok_infnan Helper for grok_number(), accepts various ways of spelling "infinity" |