X-Git-Url: http://git.mutantstargoat.com/user/nuclear/?p=rpikern;a=blobdiff_plain;f=src%2Flibc%2Fmath.c;fp=src%2Flibc%2Fmath.c;h=8da9a154296ec1ad332621eb2eaf6b5c37a36cb3;hp=0000000000000000000000000000000000000000;hb=32ccc707bc0821d7ff4248fe9f58e92e9c6ebef9;hpb=203b43a75a028e9238307bd6e73768eb8e942071

diff --git a/src/libc/math.c b/src/libc/math.c
new file mode 100644
index 0000000..8da9a15
--- /dev/null
+++ b/src/libc/math.c
@@ -0,0 +1,38 @@
+#include "math.h"
+
+static double calc_pow(double x, double y, double precision);
+
+double pow(double x, double y)
+{
+	if(y == 0.0 || y == -0.0) {
+		return 1.0;
+	}
+	if(y == 1.0) {
+		return x;
+	}
+	if(y == -INFINITY) {
+		return fabs(x) < 1.0 ? INFINITY : 0.0;
+	}
+	if(y == INFINITY) {
+		return fabs(x) < 1.0 ? 0.0 : INFINITY;
+	}
+	return calc_pow(x, y, 1e-6);
+}
+
+static double calc_pow(double x, double y, double precision)
+{
+	if(y < 0.0) {
+		return 1.0 / calc_pow(x, -y, precision);
+	}
+	if(y >= 10.0) {
+		double p = calc_pow(x, y / 2.0, precision / 2.0);
+		return p * p;
+	}
+	if(y >= 1.0) {
+		return x * calc_pow(x, y - 1.0, precision);
+	}
+	if(precision >= 1) {
+		return __builtin_sqrt(x);
+	}
+	return __builtin_sqrt(calc_pow(x, y * 2.0, precision * 2.0));
+}