Initial import

libc/math/__fpclassify.c

@@ -0,0 +1,10 @@
+#include "libc/math/math.h"
+
+int __fpclassify(double x)
+{
+	union {double f; uint64_t i;} u = {x};
+	int e = u.i>>52 & 0x7ff;
+	if (!e) return u.i<<1 ? FP_SUBNORMAL : FP_ZERO;
+	if (e==0x7ff) return u.i<<12 ? FP_NAN : FP_INFINITE;
+	return FP_NORMAL;
+}