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-rw-r--r--libm/s_isinf.c34
1 files changed, 34 insertions, 0 deletions
diff --git a/libm/s_isinf.c b/libm/s_isinf.c
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+++ b/libm/s_isinf.c
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+/*
+ * Written by J.T. Conklin <jtc@netbsd.org>.
+ * Changed to return -1 for -Inf by Ulrich Drepper <drepper@cygnus.com>.
+ * Public domain.
+ */
+
+#if defined(LIBM_SCCS) && !defined(lint)
+static char rcsid[] = "$NetBSD: s_isinf.c,v 1.3 1995/05/11 23:20:14 jtc Exp $";
+#endif
+
+/*
+ * isinf(x) returns 1 is x is inf, -1 if x is -inf, else 0;
+ * no branching!
+ */
+
+#include "math.h"
+#include "math_private.h"
+
+libm_hidden_proto(__isinf)
+int
+__isinf (double x)
+{
+ int32_t hx,lx;
+ EXTRACT_WORDS(hx,lx,x);
+ lx |= (hx & 0x7fffffff) ^ 0x7ff00000;
+ lx |= -lx;
+ return ~(lx >> 31) & (hx >> 30);
+}
+libm_hidden_def (__isinf)
+weak_alias (__isinf, isinf)
+#ifdef NO_LONG_DOUBLE
+strong_alias (__isinf, __isinfl)
+weak_alias (__isinf, isinfl)
+#endif