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authorJeff Johnston <jjohnstn@redhat.com>2014-12-15 20:50:23 +0000
committerJeff Johnston <jjohnstn@redhat.com>2014-12-15 20:50:23 +0000
commit705cda717ee7ae28c490c51ba80b55fcd38fb210 (patch)
tree316cd5736d21e59425eef58eeee7928fdd4c29c6 /newlib/libm/common/nexttowardf.c
parentf97bf8a679600a097ef0aa963e8d7295f95e6937 (diff)
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2014-12-15 Jonathan Roelofs <jonathan@codesourcery.com>
* libc/include/math.h: Add log2l,logbl,nexttowardf, * nexttoward,nexttowardl * libm/common/Makefile.am: Reference new files * libm/common/Makefile.in: Reference new files * libm/common/log2l.c: New File * libm/common/logbl.c: Likewise * libm/common/nexttowardf.c: Likewise * libm/common/nexttoward.c: Likewise * libm/common/nexttowardl.c: Likewise
Diffstat (limited to 'newlib/libm/common/nexttowardf.c')
-rw-r--r--newlib/libm/common/nexttowardf.c78
1 files changed, 78 insertions, 0 deletions
diff --git a/newlib/libm/common/nexttowardf.c b/newlib/libm/common/nexttowardf.c
new file mode 100644
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+++ b/newlib/libm/common/nexttowardf.c
@@ -0,0 +1,78 @@
+/*
+ * Copyright © 2005-2014 Rich Felker, et al.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+ * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#include <math.h>
+#include <inttypes.h>
+#include "local.h"
+
+union fshape {
+ float value;
+ uint32_t bits;
+};
+
+// This is only necessary because the implementation of isnan only works
+// properly when long double == double.
+// See: https://sourceware.org/ml/newlib/2014/msg00684.html
+#ifdef _LDBL_EQ_DOUBLE
+
+float
+nexttowardf (float x, long double y)
+{
+ union fshape ux;
+ uint32_t e;
+
+ if (isnan(x) || isnan(y))
+ return x + y;
+ if (x == y)
+ return y;
+ ux.value = x;
+ if (x == 0) {
+ ux.bits = 1;
+ if (signbit(y))
+ ux.bits |= 0x80000000;
+ } else if (x < y) {
+ if (signbit(x))
+ ux.bits--;
+ else
+ ux.bits++;
+ } else {
+ if (signbit(x))
+ ux.bits++;
+ else
+ ux.bits--;
+ }
+ e = ux.bits & 0x7f800000;
+ /* raise overflow if ux.value is infinite and x is finite */
+ if (e == 0x7f800000) {
+ volatile float force_eval;
+ force_eval = x + x;
+ }
+ /* raise underflow if ux.value is subnormal or zero */
+ if (e == 0) {
+ volatile float force_eval;
+ force_eval = x*x + ux.value*ux.value;
+ }
+ return ux.value;
+}
+
+#endif // _LDBL_EQ_DOUBLE