1 files changed, 19 insertions, 0 deletions
diff --git a/src/math/exp10.c b/src/math/exp10.c
new file mode 100644
index 00000000..7fd86fba
--- /dev/null
+++ b/src/math/exp10.c
@@ -0,0 +1,19 @@
+#define _GNU_SOURCE
+#include <math.h>
+
+double exp10(double x)
+{
+	static const double p10[] = {
+		1e-15, 1e-14, 1e-13, 1e-12, 1e-11, 1e-10,
+		1e-9, 1e-8, 1e-7, 1e-6, 1e-5, 1e-4, 1e-3, 1e-2, 1e-1,
+		1, 1e1, 1e2, 1e3, 1e4, 1e5, 1e6, 1e7, 1e8, 1e9,
+		1e10, 1e11, 1e12, 1e13, 1e14, 1e15
+	};
+	double n, y = modf(x, &n);
+	if (fabs(n) < 16) {
+		if (!y) return p10[(int)n+15];
+		y = exp2(3.32192809488736234787031942948939 * y);
+		return y * p10[(int)n+15];
+	}
+	return pow(10.0, x);
+}