Changed compass range. (#128)

The compass now always returns a positive float between 0 and 2 pi.

Author: MLanghof

src/asmcup/runtime/Robot.java

@@ -346,7 +346,7 @@ protected void handleIO(World world) {
 			vm.push8(world.recv(this, frequency));
 			break;
 		case IO_COMPASS:
-			vm.pushFloat(facing % (float)Math.PI);
+			vm.pushFloat(floatModPositive(facing, (float)(Math.PI * 2)));
 			break;
 		case IO_BEAM_DIRECTION:
 			beamDirection = popFloatSafe(-1.0f, 1.0f);
@@ -430,6 +430,10 @@ protected static float clampSafe(float f, float min, float max) {
 		return f;
 	}
 
+	protected static float floatModPositive(float dividend, float divisor) {
+		return ((dividend % divisor) + divisor) % divisor;
+	}
+	
 	public static final int IO_SENSOR = 0;
 	public static final int IO_MOTOR = 1;
 	public static final int IO_STEER = 2;