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authorJoseph Myers <joseph@codesourcery.com>2016-09-21 20:52:02 +0000
committerJoseph Myers <joseph@codesourcery.com>2016-09-21 20:52:02 +0000
commitd942e95cd7e493efbbff58b78e63013c79e634cd (patch)
treebf7eb7726729c2bc297f7e9540d3d100605df529 /math/math.h
parent5b17fd0da62bf923cb61d1bb7b08cf2e1f1f9c1a (diff)
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Add issubnormal.
TS 18661-1 adds an issubnormal classification macro to <math.h>.  This
patch implements it for glibc.  There are no new underlying functions
in libm because the implementation uses fpclassify; any optimizations
for this macro should be done through adding __builtin_subnormal 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.

The intended structure of the NEWS entry for <math.h> features from TS
18661-1 is like:

* New <math.h> features are added from TS 18661-1:2014:

  - Nearest integer functions: roundeven, roundevenf, roundevenl.

  - Comparison macros: iseqsig.

  - Classification macros: iscanonical, issubnormal, iszero.

(that is, following the grouping of interfaces in TS 18661-1:2014,
with any group where any interfaces are new in glibc 2.25 being listed
like that).

Tested for x86_64 and x86.

	* math/math.h [__GLIBC_USE (IEC_60559_BFP_EXT)] (issubnormal): New
	macro.
	* math/libm-test.inc (issubnormal_test_data): New array.
	(issubnormal_test): New function.
	* manual/arith.texi (Floating Point Classes): Document
	issubnormal.
	* manual/libm-err-tab.pl: Update comment on interfaces without
	ulps tabulated.
Diffstat (limited to 'math/math.h')
-rw-r--r--math/math.h3
1 files changed, 3 insertions, 0 deletions
diff --git a/math/math.h b/math/math.h
index 2f77deec87..064cc56e1b 100644
--- a/math/math.h
+++ b/math/math.h
@@ -328,6 +328,9 @@ enum
       : sizeof (x) == sizeof (double)					      \
       ? __issignaling (x) : __issignalingl (x))
 # endif
+
+/* Return nonzero value if X is subnormal.  */
+# define issubnormal(x) (fpclassify (x) == FP_SUBNORMAL)
 #endif /* Use IEC_60559_BFP_EXT.  */
 
 #ifdef	__USE_MISC