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-rw-r--r--sysdeps/libm-ieee754/s_isinf.c32
1 files changed, 32 insertions, 0 deletions
diff --git a/sysdeps/libm-ieee754/s_isinf.c b/sysdeps/libm-ieee754/s_isinf.c
new file mode 100644
index 0000000000..a54d97cba6
--- /dev/null
+++ b/sysdeps/libm-ieee754/s_isinf.c
@@ -0,0 +1,32 @@
+/*
+ * Written by J.T. Conklin <jtc@netbsd.org>.
+ * 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, else 0;
+ * no branching!
+ */
+
+#include "math.h"
+#include "math_private.h"
+
+#ifdef __STDC__
+	int __isinf(double x)
+#else
+	int __isinf(x)
+	double x;
+#endif
+{
+	int32_t hx,lx;
+	EXTRACT_WORDS(hx,lx,x);
+	hx &= 0x7fffffff;
+	hx ^= 0x7ff00000;
+	hx |= lx;
+	return (hx == 0);
+}
+weak_alias (__isinf, isinf)