Decompile sinf.c

src/libultra/gu/sinf.c

@@ -0,0 +1,89 @@
+#include <guint.h>
+
+// TODO find these values wherever they are in .rodata
+// TODO these can't be defined in here yet because we strip out the .rodata for each object
+//static const du P[5];
+
+//static const du rpi;
+
+//static const du pihi;
+
+//static const du pilo;
+
+//static const fu zero;
+
+extern du P[5];
+
+extern du rpi;
+
+extern du pihi;
+
+extern du pilo;
+
+extern fu zero;
+
+extern float __libm_qnan_f;
+
+float __sinf(float x) {
+    double dx; // double x
+    double xsq; // x squared
+    double poly;
+    double dn;
+    int n;
+    double result;
+    int ix; // int x
+	int xpt;
+
+	ix = *(int*)&x;
+	xpt = (ix >> 22) & 0x1FF;
+
+	if (xpt < 255) {
+		dx = x;
+		if (xpt >= 230) {
+			xsq = dx * dx;
+
+			poly = (((((P[4].d * xsq) + P[3].d) * xsq) + P[2].d) * xsq) + P[1].d;
+
+			result = ((dx * xsq) * poly) + dx;
+
+			return result;
+		} else {
+			return x;
+		}
+	}
+
+	if (xpt < 310) {
+		dx = x;
+
+		dn = dx * rpi.d;
+
+		if (dn >= 0) {
+			n = dn + 0.5;
+		} else {
+			n = dn - 0.5;
+		}
+
+		dn = n;
+
+		dx -= dn * pihi.d;
+		dx -= dn * pilo.d;
+
+		xsq = dx * dx;
+
+		poly = (((((P[4].d * xsq) + P[3].d) * xsq) + P[2].d) * xsq) + P[1].d;
+
+		result = ((dx * xsq) * poly) + dx;
+
+		if ((n & 0x1) == 0) {
+			return result;
+		} else {
+			return -(float)result;
+		}
+	}
+
+	if (x != x) {
+		return __libm_qnan_f;
+	}
+
+	return zero.f;
+}