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authorJoseph Myers <joseph@codesourcery.com>2016-10-12 01:20:30 +0000
committerJoseph Myers <joseph@codesourcery.com>2016-10-12 01:20:30 +0000
commit5e9d98a3d9eec0a18e6875f6e86a3886fbb7e543 (patch)
treea4468dc50bae278c8ba8712e5953689b2be043f2 /manual/arith.texi
parent5da2c626a53bb3d4cfcdf773d94a153d8408d45b (diff)
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Add totalorder, totalorderf, totalorderl.
TS 18661-1 defines totalorder functions implementing the totalOrder
comparison operation from IEEE 754-2008.  This patch implements these
functions for glibc, including the type-generic macro in <tgmath.h>.
(The totalordermag functions will be added in a separate patch.)

The description of the totalOrder operation is complicated.  However,
for IEEE interchange binary formats and the preferred quiet NaN
convention, what that complicated description means is that you
interpret the representation as a sign-magnitude integer (with -0
coming before +0) and do a <= comparison on that interpretation.  For
finite values and infinities the ordering of the sign-magnitude
integers is just the same as the ordering of floating-point values, so
this extends that to all representations.  (Different representations
of the same floating-point value - which includes same quantum in the
decimal case - must still be considered equal by this operation, but
that issue doesn't arise for IEEE interchange binary formats.)  So the
complications are:

* When MIPS quiet NaN conventions are in use, the representation of
  NaNs needs adjusting before making such an integer comparison.  This
  patch does this adjustment only when both arguments are NaNs, as
  there's no need for it if only one is a NaN, and as long as both are
  NaNs you can just flip the relevant bits without any problems from
  this turning a NaN into an infinity.

* For the m68k version of ldbl-96, where the high mantissa bit is
  "don't care" for infinities and NaNs, representations where it
  differs must compare the same.  Note: although the testcase for this
  compiles, I have not actually tested on m68k.

* For ldbl-128ibm, the low part must be ignored when the high part is
  NaN, and low parts of +0 and -0 must be considered the same whatever
  the high part.

The new tests in libm-test.inc are the first tests there specifying
particular payloads for input NaNs.  Separate tests are also added for
the ldbl-96 and ldbl-128ibm special cases where there are different
representations of the same value that must compare equal (which can't
be covered in libm-test.inc as that only specifies values, not
representations).

Tested for x86_64, x86, mips64 and powerpc.

	* math/bits/mathcalls.h [__GLIBC_USE (IEC_60559_BFP_EXT)]
	(totalorder): New declaration.
	* math/tgmath.h [__GLIBC_USE (IEC_60559_BFP_EXT)] (totalorder):
	New macro.
	* math/Versions (totalorder): New libm symbol at version
	GLIBC_2.25.
	(totalorderf): Likewise.
	(totalorderl): Likewise.
	* math/Makefile (libm-calls): Add s_totalorderF.
	* math/gen-libm-test.pl (parse_args): Escape quotes in test name
	string.
	* math/libm-test.inc (PAYLOAD_DIG): New macro.
	(qnan_value_pl): Likewise.
	(snan_value_pl): Likewise.
	(qnan_value): Define using qnan_value_pl.
	(snan_value): Define using snan_value_pl.
	(struct test_ff_i_data): Add comment about which tests use this
	structure.
	(RUN_TEST_ff_b): New macro.
	(RUN_TEST_LOOP_ff_b): Likewise.
	(totalorder_test_data): New array.
	(totalorder_test): New function.
	(main): Call totalorder_test.
	* math/test-tgmath.c (NCALLS): Increase to 122.
	(F(compile_test)): Call totalorder.
	(F(totalorder)): New function.
	* manual/arith.texi (FP Comparison Functions): Document
	totalorder, totalorderf and totalorderl.
	* manual/libm-err-tab.pl: Update comment on interfaces without
	ulps tabulated.
	* sysdeps/ieee754/dbl-64/s_totalorder.c: New file.
	* sysdeps/ieee754/dbl-64/wordsize-64/s_totalorder.c: Likewise.
	* sysdeps/ieee754/flt-32/s_totalorderf.c: Likewise.
	* sysdeps/ieee754/ldbl-128/s_totalorderl.c: Likewise.
	* sysdeps/ieee754/ldbl-128ibm/s_totalorderl.c: Likewise.
	* sysdeps/ieee754/ldbl-96/s_totalorderl.c: Likewise.
	* sysdeps/ieee754/ldbl-opt/nldbl-totalorder.c: Likewise.
	* sysdeps/ieee754/ldbl-opt/Makefile (libnldbl-calls): Add
	totalorder.
	(CFLAGS-nldbl-totalorder.c): New variable.
	* sysdeps/ieee754/ldbl-128ibm/test-totalorderl-ldbl-128ibm.c: New
	file.
	* sysdeps/ieee754/ldbl-128ibm/Makefile [$(subdir) = math] (tests):
	Add test-totalorderl-ldbl-128ibm.
	* sysdeps/ieee754/ldbl-96/test-totalorderl-ldbl-96.c: New file.
	* sysdeps/ieee754/ldbl-96/Makefile [$(subdir) = math] (tests): Add
	test-totalorderl-ldbl-96.
	* sysdeps/nacl/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/aarch64/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/alpha/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/arm/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/hppa/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/i386/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/ia64/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/m68k/coldfire/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/m68k/m680x0/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/microblaze/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/mips/mips32/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/mips/mips64/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/nios2/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libm.abilist:
	Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libm.abilist:
	Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/libm-le.abilist:
	Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/libm.abilist:
	Likewise.
	* sysdeps/unix/sysv/linux/s390/s390-32/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/s390/s390-64/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/sh/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/sparc/sparc32/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/sparc/sparc64/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libm.abilist:
	Likewise.
	* sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libm.abilist:
	Likewise.
	* sysdeps/unix/sysv/linux/tile/tilepro/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/x86_64/64/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/x86_64/x32/libm.abilist: Likewise.
Diffstat (limited to 'manual/arith.texi')
-rw-r--r--manual/arith.texi27
1 files changed, 26 insertions, 1 deletions
diff --git a/manual/arith.texi b/manual/arith.texi
index 5fb18f3561..75d34c8427 100644
--- a/manual/arith.texi
+++ b/manual/arith.texi
@@ -1874,7 +1874,10 @@ do not raise exceptions when NaN is examined.  All of the functions are
 implemented as macros which allow their arguments to be of any
 floating-point type.  The macros are guaranteed to evaluate their
 arguments only once.  TS 18661-1:2014 adds such a macro for an
-equality comparison that @emph{does} raise an exception for a NaN argument.
+equality comparison that @emph{does} raise an exception for a NaN
+argument; it also adds functions that provide a total ordering on all
+floating-point values, including NaNs, without raising any exceptions
+even for signaling NaNs.
 
 @comment math.h
 @comment ISO
@@ -1943,6 +1946,28 @@ exception and sets @code{errno} to @code{EDOM} is either argument is a
 NaN.
 @end deftypefn
 
+@comment math.h
+@comment ISO
+@deftypefun int totalorder (double @var{x}, double @var{y})
+@comment ISO
+@deftypefunx int totalorderf (float @var{x}, float @var{y})
+@comment ISO
+@deftypefunx int totalorderl (long double @var{x}, long double @var{y})
+@safety{@prelim{}@mtsafe{}@assafe{}@acsafe{}}
+These functions determine whether the total order relationship,
+defined in IEEE 754-2008, is true for @var{x} and @var{y}, returning
+nonzero if it is true and zero if it is false.  No exceptions are
+raised even for signaling NaNs.  The relationship is true if they are
+the same floating-point value (including sign for zero and NaNs, and
+payload for NaNs), or if @var{x} comes before @var{y} in the following
+order: negative quiet NaNs, in order of decreasing payload; negative
+signaling NaNs, in order of decreasing payload; negative infinity;
+finite numbers, in ascending order, with negative zero before positive
+zero; positive infinity; positive signaling NaNs, in order of
+increasing payload; positive quiet NaNs, in order of increasing
+payload.
+@end deftypefun
+
 Not all machines provide hardware support for these operations.  On
 machines that don't, the macros can be very slow.  Therefore, you should
 not use these functions when NaN is not a concern.