Implemented Adlib Gold mixer.

src/filters.h

@@ -176,3 +176,106 @@ static inline float sb_iir(int i, float NewSample) {
     return y[i][0];
 }
 
+
+
+#undef NCoef
+#define NCoef 2
+
+//fc=150Hz
+static inline float adgold_highpass_iir(int i, float NewSample) {
+    float ACoef[NCoef+1] = {
+        0.98657437157334349000,
+        -1.97314874314668700000,
+        0.98657437157334349000
+    };
+
+    float BCoef[NCoef+1] = {
+        1.00000000000000000000,
+        -1.97223372919758360000,
+        0.97261396931534050000
+    };
+
+    static float y[2][NCoef+1]; //output samples
+    static float x[2][NCoef+1]; //input samples
+    int n;
+
+    //shift the old samples
+    for(n=NCoef; n>0; n--) {
+       x[i][n] = x[i][n-1];
+       y[i][n] = y[i][n-1];
+    }
+
+    //Calculate the new output
+    x[i][0] = NewSample;
+    y[i][0] = ACoef[0] * x[i][0];
+    for(n=1; n<=NCoef; n++)
+        y[i][0] += ACoef[n] * x[i][n] - BCoef[n] * y[i][n];
+    
+    return y[i][0];
+}
+
+//fc=150Hz
+static inline float adgold_lowpass_iir(int i, float NewSample) {
+    float ACoef[NCoef+1] = {
+        0.00009159473951071446,
+        0.00018318947902142891,
+        0.00009159473951071446
+    };
+
+    float BCoef[NCoef+1] = {
+        1.00000000000000000000,
+        -1.97223372919526560000,
+        0.97261396931306277000
+    };
+
+    static float y[2][NCoef+1]; //output samples
+    static float x[2][NCoef+1]; //input samples
+    int n;
+
+    //shift the old samples
+    for(n=NCoef; n>0; n--) {
+       x[i][n] = x[i][n-1];
+       y[i][n] = y[i][n-1];
+    }
+
+    //Calculate the new output
+    x[i][0] = NewSample;
+    y[i][0] = ACoef[0] * x[i][0];
+    for(n=1; n<=NCoef; n++)
+        y[i][0] += ACoef[n] * x[i][n] - BCoef[n] * y[i][n];
+    
+    return y[i][0];
+}
+
+//fc=56Hz
+static inline float adgold_pseudo_stereo_iir(float NewSample) {
+    float ACoef[NCoef+1] = {
+        0.00001409030866231767,
+        0.00002818061732463533,
+        0.00001409030866231767
+    };
+
+    float BCoef[NCoef+1] = {
+        1.00000000000000000000,
+        -1.98733021473466760000,
+        0.98738361004063568000
+    };
+
+    static float y[NCoef+1]; //output samples
+    static float x[NCoef+1]; //input samples
+    int n;
+
+    //shift the old samples
+    for(n=NCoef; n>0; n--) {
+       x[n] = x[n-1];
+       y[n] = y[n-1];
+    }
+
+    //Calculate the new output
+    x[0] = NewSample;
+    y[0] = ACoef[0] * x[0];
+    for(n=1; n<=NCoef; n++)
+        y[0] += ACoef[n] * x[n] - BCoef[n] * y[n];
+    
+    return y[0];
+}