NEW: math.h/libmath.c

src/userland/libc/libmath.c

@@ -0,0 +1,157 @@
+// Copyright (c) 2023-2026 Chris (boreddevnl)
+// This software is released under the GNU General Public License v3.0. See LICENSE file for details.
+// This header needs to maintain in any file it is present in, as per the GPL license terms.
+
+#include "math.h"
+static double _pow_int(double b, int e) {
+    if (e == 0) return 1.0;
+    if (e < 0) { return 1.0 / _pow_int(b, -e); }
+    double r = 1.0;
+    while (e > 0) {
+        if (e & 1) r *= b;
+        b *= b;
+        e >>= 1;
+    }
+    return r;
+}
+double fabs(double x) {
+    return x < 0.0 ? -x : x;
+}
+double fmod(double x, double y) {
+    if (y == 0.0) return 0.0;
+    return x - (int)(x / y) * y;
+}
+
+double floor(double x) {
+    int i = (int)x;
+    return (x < 0.0 && (double)i != x) ? (double)(i - 1) : (double)i;
+}
+
+double ceil(double x) {
+    int i = (int)x;
+    return (x > 0.0 && (double)i != x) ? (double)(i + 1) : (double)i;
+}
+
+double sin(double x) {
+    x = fmod(x, 2.0 * M_PI);
+    if (x > M_PI)  x -= 2.0 * M_PI;
+    if (x < -M_PI) x += 2.0 * M_PI;
+
+    double x2 = x * x;
+    double term = x;
+    double sum  = x;
+    for (int i = 1; i <= 8; i++) {
+        term *= -x2 / ((2*i) * (2*i + 1));
+        sum  += term;
+    }
+    return sum;
+}
+
+double cos(double x) {
+    return sin(x + M_PI / 2.0);
+}
+
+double tan(double x) {
+    double c = cos(x);
+    if (fabs(c) < 1e-10) return 1e15;   
+    return sin(x) / c;
+}
+
+double sqrt(double x) {
+    if (x <= 0.0) return 0.0;
+    double g = x * 0.5;
+    for (int i = 0; i < 25; i++) {
+        g = (g + x / g) * 0.5;
+    }
+    return g;
+}
+
+double log(double x) {
+    if (x <= 0.0) return -1e30;
+
+    int e = 0;
+    while (x > 2.0)  { x /= 2.0; e++; }
+    while (x < 0.5)  { x *= 2.0; e--; }
+
+    double t  = (x - 1.0) / (x + 1.0);
+    double t2 = t * t;
+    double sum = t, term = t;
+    for (int i = 1; i <= 20; i++) {
+        term *= t2;
+        sum  += term / (2*i + 1);
+    }
+    return 2.0 * sum + e * M_LN2;
+}
+
+double log2(double x) {
+    // log2(x) = ln(x) / ln(2)
+    return log(x) / M_LN2;
+}
+
+double log10(double x) {
+    return log(x) / 2.302585092994046;
+}
+
+double exp(double x) {
+    if (x >  700.0) return 1e300;   
+    if (x < -700.0) return 0.0;     
+
+    int k = (int)(x / M_LN2);
+    if (x < 0.0 && (double)k * M_LN2 > x) k--;
+    double r = x - (double)k * M_LN2;
+
+    double sum = 1.0, term = 1.0;
+    for (int i = 1; i <= 20; i++) {
+        term *= r / (double)i;
+        sum  += term;
+    }
+
+    double result = sum;
+    if (k >= 0) { for (int i = 0; i < k;  i++) result *= 2.0; }
+    else        { for (int i = 0; i < -k; i++) result /= 2.0; }
+    return result;
+}
+double pow(double base, double exponent) {
+    if (base == 0.0)  return 0.0;
+    if (exponent == 0.0) return 1.0;
+    int ie = (int)exponent;
+    if ((double)ie == exponent) return _pow_int(base, ie);
+
+    if (base < 0.0) return 0.0;  
+    return exp(exponent * log(base));
+}
+
+double sinh(double x) {
+    double ep = exp(x);
+    double em = exp(-x);
+    return (ep - em) * 0.5;
+}
+
+double cosh(double x) {
+    double ep = exp(x);
+    double em = exp(-x);
+    return (ep + em) * 0.5;
+}
+
+double tanh(double x) {
+    double e2 = exp(2.0 * x);
+    return (e2 - 1.0) / (e2 + 1.0);
+}
+
+double hypot(double x, double y) {
+    return sqrt(x*x + y*y);
+}
+
+double fmin(double a, double b) {
+    return a < b ? a : b;
+}
+
+double fmax(double a, double b) {
+    return a > b ? a : b;
+}
+
+double fclamp(double x, double lo, double hi) {
+    if (x < lo) return lo;
+    if (x > hi) return hi;
+    return x;
+}

src/userland/libc/math.h

@@ -0,0 +1,40 @@
+// Copyright (c) 2023-2026 Chris (boreddevnl)
+// This software is released under the GNU General Public License v3.0. See LICENSE file for details.
+// This header needs to maintain in any file it is present in, as per the GPL license terms.
+
+#ifndef MATH_H
+#define MATH_H
+
+#define M_PI        3.14159265358979323846
+#define M_E         2.71828182845904523536
+#define M_LN2       0.69314718055994530942
+#define M_SQRT2     1.41421356237309504880
+#define HUGE_VAL    (1e300 * 1e300)  
+
+double fabs(double x);
+
+double fmod(double x, double y);
+
+double floor(double x);
+
+double ceil(double x);
+
+double sin(double x);
+double cos(double x);
+double tan(double x);
+double sqrt(double x);
+
+double log(double x);
+double log2(double x);
+double log10(double x);
+double exp(double x);
+double pow(double base, double exponent);
+double sinh(double x);
+double cosh(double x);
+double tanh(double x);
+double hypot(double x, double y);
+double fmin(double a, double b);
+double fmax(double a, double b);
+double fclamp(double x, double lo, double hi);
+
+#endif /* MATH_H */