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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)
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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 5fb18f3..75d34c8 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.