Implemented math.h

libc/math/exp.c

@@ -0,0 +1,46 @@
+#include <math.h>
+
+#define _EXP_TAYLOR_TERMS   10
+#define _EXP2_TAYLOR_TERMS  5
+
+double exp(double x) {
+    if (x == 0.0) return 1.0;
+    if (x < 0.0) return 1.0 / exp(-x);
+
+    double sum = 1.0;   // Result
+    double term = 1.0;  // Curent term in the series
+    
+    /*
+     Calculate the Taylor series:
+     e^x = 1 + x + x^2/2! + x^3/3! + ...
+     */
+    for (int i = 1; i < _EXP_TAYLOR_TERMS; i++) {
+        term *= x / (double)i;
+        sum += term;
+    }
+
+    return sum;
+}
+
+double exp2(double x) {
+    if (x == 0.0) return 1.0;
+    if (x < 0.0) return 1.0 / exp2(-x);
+
+    int n = (int)x;     // Integer part
+    double frac = x - n;// Fractional part
+
+    // Integer power of 2
+    double result = (double)(1 << n);   // 2^n is just 1 << n
+
+    // Approximate the fractional part
+    double sum = 1.0;
+    double term = frac;
+
+    for (int i = 1; i < _EXP2_TAYLOR_TERMS; i++) {
+        sum += term;
+        term *= frac / (i+1);
+    }
+
+    return result * sum;
+}
+