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-rw-r--r--src/math/exp10f.c17
1 files changed, 17 insertions, 0 deletions
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);
+}