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-rw-r--r--libm/s_isinff.c30
1 files changed, 30 insertions, 0 deletions
diff --git a/libm/s_isinff.c b/libm/s_isinff.c
new file mode 100644
index 0000000..33e2749
--- /dev/null
+++ b/libm/s_isinff.c
@@ -0,0 +1,30 @@
+/*
+ * Written by J.T. Conklin <jtc@netbsd.org>.
+ * Public domain.
+ */
+
+#if defined(LIBM_SCCS) && !defined(lint)
+static char rcsid[] = "$NetBSD: s_isinff.c,v 1.3 1995/05/11 23:20:21 jtc Exp $";
+#endif
+
+/*
+ * isinff(x) returns 1 if x is inf, -1 if x is -inf, else 0;
+ * no branching!
+ */
+
+#include "math.h"
+#include "math_private.h"
+
+libm_hidden_proto(__isinff)
+int
+__isinff (float x)
+{
+ int32_t ix,t;
+ GET_FLOAT_WORD(ix,x);
+ t = ix & 0x7fffffff;
+ t ^= 0x7f800000;
+ t |= -t;
+ return ~(t >> 31) & (ix >> 30);
+}
+libm_hidden_def (__isinff)
+weak_alias (__isinff, isinff)