Implement & link jaudio_NES/random.c

src/static/jaudio_NES/internal/random.c

@@ -0,0 +1,28 @@
+#include "jaudio_NES/random.h"
+
+static s32 v0 = 0x0001000;
+static s32 v1 = 0x0005555;
+
+#define V0_MULT (s32)0x13579BDE
+#define V1_MULT (s32)0x98765432
+
+extern s32 GetRandom_s32(void) {
+    s32 tmp;
+
+    tmp = (v1 * V1_MULT) + ((v0 * V0_MULT) >> 4);
+    tmp += 1;
+    v0 = v1;
+    v1 = tmp;
+    return tmp;
+}
+
+extern f32 GetRandom_sf32(void) {
+    s32 rnd = GetRandom_s32();
+    f32 rnd_float = (f32)(rnd & 0x00FFFFFF) / (f32)(0x00FFFFFF); /* map to float [0, 1] */
+
+    if (rnd < 0) {
+        rnd_float = -rnd_float;
+    }
+
+    return rnd_float;
+}