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authorJoseph Myers <josmyers@redhat.com>2024-05-20 13:41:39 +0000
committerJoseph Myers <josmyers@redhat.com>2024-05-20 13:41:39 +0000
commit79c52daf4740b00bef43e4f5a4281b3480459b38 (patch)
treecc15e0f7402870b20dbebf8d539df033806d48b0 /sysdeps/ieee754/ldbl-opt
parentcf0ca8d52e1653d4aa4311a4649af8dc541ce6b4 (diff)
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Implement C23 log2p1
C23 adds various <math.h> function families originally defined in TS 18661-4. Add the log2p1 functions (log2(1+x): like log1p, but for base-2 logarithms). This illustrates the intended structure of implementations of all these function families: define them initially with a type-generic template implementation. If someone wishes to add type-specific implementations, it is likely such implementations can be both faster and more accurate than the type-generic one and can then override it for types for which they are implemented (adding benchmarks would be desirable in such cases to demonstrate that a new implementation is indeed faster). The test inputs are copied from those for log1p. Note that these changes make gen-auto-libm-tests depend on MPFR 4.2 (or later). The bulk of the changes are fairly generic for any such new function. (sysdeps/powerpc/nofpu/Makefile only needs changing for those type-generic templates that use fabs.) Tested for x86_64 and x86, and with build-many-glibcs.py.
Diffstat (limited to 'sysdeps/ieee754/ldbl-opt')
-rw-r--r--sysdeps/ieee754/ldbl-opt/Makefile4
-rw-r--r--sysdeps/ieee754/ldbl-opt/nldbl-log2p1.c8
2 files changed, 11 insertions, 1 deletions
diff --git a/sysdeps/ieee754/ldbl-opt/Makefile b/sysdeps/ieee754/ldbl-opt/Makefile
index 74788ac..8072761 100644
--- a/sysdeps/ieee754/ldbl-opt/Makefile
+++ b/sysdeps/ieee754/ldbl-opt/Makefile
@@ -51,7 +51,8 @@ libnldbl-calls = asprintf dprintf fprintf fscanf fwprintf fwscanf iovfscanf \
roundeven fromfp ufromfp fromfpx ufromfpx fadd dadd \
fdiv ddiv ffma dfma fmul dmul fsqrt dsqrt fsub dsub \
fmaximum fmaximum_mag fmaximum_num fmaximum_mag_num \
- fminimum fminimum_mag fminimum_num fminimum_mag_num
+ fminimum fminimum_mag fminimum_num fminimum_mag_num \
+ log2p1
libnldbl-routines = $(libnldbl-calls:%=nldbl-%)
libnldbl-inhibit-o = $(object-suffixes)
libnldbl-static-only-routines = $(libnldbl-routines)
@@ -151,6 +152,7 @@ CFLAGS-nldbl-log.c = -fno-builtin-logl
CFLAGS-nldbl-log10.c = -fno-builtin-log10l
CFLAGS-nldbl-log1p.c = -fno-builtin-log1pl
CFLAGS-nldbl-log2.c = -fno-builtin-log2l
+CFLAGS-nldbl-log2p1.c = -fno-builtin-log2p1l
CFLAGS-nldbl-logb.c = -fno-builtin-logbl
CFLAGS-nldbl-lrint.c = -fno-builtin-lrintl
CFLAGS-nldbl-lround.c = -fno-builtin-lroundl
diff --git a/sysdeps/ieee754/ldbl-opt/nldbl-log2p1.c b/sysdeps/ieee754/ldbl-opt/nldbl-log2p1.c
new file mode 100644
index 0000000..989c69e
--- /dev/null
+++ b/sysdeps/ieee754/ldbl-opt/nldbl-log2p1.c
@@ -0,0 +1,8 @@
+#include "nldbl-compat.h"
+
+double
+attribute_hidden
+log2p1l (double x)
+{
+ return log2p1 (x);
+}