From bb8081f57f23a3e1b28b1b7104f24d17da9a3d82 Mon Sep 17 00:00:00 2001 From: Joseph Myers Date: Fri, 23 Sep 2016 21:54:21 +0000 Subject: Add iszero. TS 18661-1 adds an iszero classification macro to . This patch implements it for glibc. There are no new underlying functions in libm because the implementation uses fpclassify when sNaN support is required and a direct comparison otherwise; any optimizations for this macro should be done through adding __builtin_iszero in GCC and using it in the header for suitable GCC versions, not through adding other optimized inline or out-of-line versions to glibc. Tested for x86_64 and x86. * math/math.h [__GLIBC_USE (IEC_60559_BFP_EXT)] (iszero): New macro. * math/libm-test.inc (iszero_test_data): New array. (iszero_test): New function. (main): Call iszero_test. * manual/arith.texi (Floating Point Classes): Document iszero. * manual/libm-err-tab.pl: Update comment on interfaces without ulps tabulated. --- math/math.h | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'math/math.h') diff --git a/math/math.h b/math/math.h index 064cc56e1b..0a099596f1 100644 --- a/math/math.h +++ b/math/math.h @@ -331,6 +331,13 @@ enum /* Return nonzero value if X is subnormal. */ # define issubnormal(x) (fpclassify (x) == FP_SUBNORMAL) + +/* Return nonzero value if X is zero. */ +# ifdef __SUPPORT_SNAN__ +# define iszero(x) (fpclassify (x) == FP_ZERO) +# else +# define iszero(x) ((x) == 0) +# endif #endif /* Use IEC_60559_BFP_EXT. */ #ifdef __USE_MISC -- cgit v1.2.3