4 files changed, 59 insertions, 0 deletions
diff --git a/include/math.h b/include/math.h
index bc0159e6..65b1e915 100644
--- a/include/math.h
+++ b/include/math.h
@@ -387,6 +387,10 @@ float       y1f(float);
 long double y1l(long double);
 float       ynf(int, float);
 long double ynl(int, long double);
+
+double      exp10(double);
+float       exp10f(float);
+long double exp10l(long double);
 #endif
 
 #ifdef __cplusplus
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);
+}
diff --git a/src/math/exp10f.c b/src/math/exp10f.c
new file mode 100644
index 00000000..c9521411
--- /dev/null
+++ b/src/math/exp10f.c
@@ -0,0 +1,17 @@
+#define _GNU_SOURCE
+#include <math.h>
+
+float exp10f(float x)
+{
+	static const float p10[] = {
+		1e-7, 1e-6, 1e-5, 1e-4, 1e-3, 1e-2, 1e-1,
+		1, 1e1, 1e2, 1e3, 1e4, 1e5, 1e6, 1e7
+	};
+	float n, y = modff(x, &n);
+	if (fabsf(n) < 8) {
+		if (!y) return p10[(int)n+7];
+		y = exp2f(3.32192809488736234787031942948939f * y);
+		return y * p10[(int)n+7];
+	}
+	return exp2(3.32192809488736234787031942948939 * x);
+}
diff --git a/src/math/exp10l.c b/src/math/exp10l.c
new file mode 100644
index 00000000..4d0c5a01
--- /dev/null
+++ b/src/math/exp10l.c
@@ -0,0 +1,19 @@
+#define _GNU_SOURCE
+#include <math.h>
+
+long double exp10l(long double x)
+{
+	static const long 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
+	};
+	long double n, y = modfl(x, &n);
+	if (fabsl(n) < 16) {
+		if (!y) return p10[(int)n+15];
+		y = exp2l(3.32192809488736234787031942948939L * y);
+		return y * p10[(int)n+15];
+	}
+	return powl(10.0, x);
+}