README updates, CRTC tests.

- Added more CRTC information to the README file.
- Added unit tests for the CRTC.
- Implemented register read for cursor position in the CRTC.
- Bundling a new version of jterminal that has correct backspace
  behavior.

src/test/java/com/loomcom/symon/CrtcTest.java

@@ -0,0 +1,343 @@
+package com.loomcom.symon;
+
+import com.loomcom.symon.devices.Crtc;
+import com.loomcom.symon.devices.DeviceChangeListener;
+import com.loomcom.symon.devices.Memory;
+import com.loomcom.symon.exceptions.MemoryAccessException;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.runners.MockitoJUnitRunner;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+import static org.mockito.Mockito.*;
+
+@RunWith(MockitoJUnitRunner.class)
+public class CrtcTest {
+
+    Crtc crtc;
+
+    @Mock
+    DeviceChangeListener changeListener;
+    @Mock
+    Memory memory;
+
+    @Before
+    public void createDevices() throws Exception {
+        crtc = new Crtc(0x9000, memory);
+        crtc.registerListener(changeListener);
+
+        when(memory.startAddress()).thenReturn(0);
+        when(memory.endAddress()).thenReturn(0x7fff);
+    }
+
+    @Test
+    public void selectingRegisterDoesNotTriggedrCallback() throws Exception {
+        crtc.write(0, 1);
+
+        verify(changeListener, never()).deviceStateChanged();
+    }
+
+    @Test
+    public void shouldChangeHorizontalDisplayed() throws Exception {
+        crtc.write(0, 1);
+
+        crtc.write(1, 80);
+        assertEquals(80, crtc.getHorizontalDisplayed());
+
+        crtc.write(1, 40);
+        assertEquals(40, crtc.getHorizontalDisplayed());
+    }
+
+    @Test
+    public void changeHorizontalDisplayedShouldTriggerCallback() throws Exception {
+        crtc.write(0, 1);
+
+        crtc.write(1, 80);
+        verify(changeListener, times(1)).deviceStateChanged();
+    }
+
+
+    @Test
+    public void shouldChangeVerticalDisplayed() throws Exception {
+        crtc.write(0, 6);
+
+        crtc.write(1, 23);
+        assertEquals(23, crtc.getVerticalDisplayed());
+
+        crtc.write(1, 26);
+        assertEquals(26, crtc.getVerticalDisplayed());
+    }
+
+    @Test
+    public void changeVerticalDisplayedShouldTriggerCallback() throws Exception {
+        crtc.write(0, 6);
+
+        crtc.write(1, 23);
+
+        verify(changeListener, times(1)).deviceStateChanged();
+    }
+
+    @Test
+    public void shouldChangeScanLinesPerRow() throws Exception {
+        crtc.write(0, 9); // Select register 9, Scan Line
+
+        crtc.write(1, 3);
+        assertEquals(3, crtc.getScanLinesPerRow());
+
+        crtc.write(1, 5);
+        assertEquals(5, crtc.getScanLinesPerRow());
+
+        crtc.write(1, 9);
+        assertEquals(9, crtc.getScanLinesPerRow());
+    }
+
+    @Test
+    public void changeScanLinesPerRowShouldTriggerCallback() throws Exception {
+        crtc.write(0, 9); // Select register 9, Scan Line
+
+        crtc.write(1, 3);
+
+        verify(changeListener, times(1)).deviceStateChanged();
+    }
+
+    @Test
+    public void shouldChangeCursorStartLine() throws Exception {
+        crtc.write(0, 10);
+
+        crtc.write(1, 0);
+        assertEquals(0, crtc.getCursorStartLine());
+
+        crtc.write(1, 1);
+        assertEquals(1, crtc.getCursorStartLine());
+
+        crtc.write(1, 4);
+        assertEquals(4, crtc.getCursorStartLine());
+    }
+
+    @Test
+    public void changeCursorStartLineShouldTriggerCallback() throws Exception {
+        crtc.write(0, 10);
+
+        crtc.write(1, 5);
+
+        verify(changeListener, times(1)).deviceStateChanged();
+    }
+
+    @Test
+    public void cursorStartLineRegisterChangesCursorVisibility() throws Exception {
+        crtc.write(0, 10);
+
+        crtc.write(1, 0x00); // Start line 0, no blinking.
+
+        assertEquals(0, crtc.getCursorStartLine());
+        assertEquals(0, crtc.getCursorBlinkRate());
+        assertTrue(crtc.isCursorEnabled());
+
+        crtc.write(1, 0x23); // Start line 3, no cursor.
+
+        assertEquals(3, crtc.getCursorStartLine());
+        assertEquals(0, crtc.getCursorBlinkRate());
+        assertFalse(crtc.isCursorEnabled());
+    }
+
+    @Test
+    public void cursorStartLineRegisterChangesCursorBlinkRate() throws Exception {
+        crtc.write(0, 10);
+
+        crtc.write(1, 0x40); // Start line 0, 500ms blink delay
+
+        assertEquals(0, crtc.getCursorStartLine());
+        assertEquals(500, crtc.getCursorBlinkRate());
+        assertTrue(crtc.isCursorEnabled());
+
+        crtc.write(1, 0x62); // Start line 3, 1000ms blink delay
+
+        assertEquals(2, crtc.getCursorStartLine());
+        assertEquals(1000, crtc.getCursorBlinkRate());
+        assertTrue(crtc.isCursorEnabled());
+    }
+
+
+    @Test
+    public void shouldChangeCursorStopLine() throws Exception {
+        crtc.write(0, 11);
+
+        crtc.write(1, 0);
+        assertEquals(0, crtc.getCursorStopLine());
+
+        crtc.write(1, 3);
+        assertEquals(3, crtc.getCursorStopLine());
+
+        crtc.write(1, 6);
+        assertEquals(6, crtc.getCursorStopLine());
+    }
+
+    @Test
+    public void changeCursorStopLineShouldTriggerCallback() throws Exception {
+        crtc.write(0, 11);
+
+        crtc.write(1, 7);
+
+        verify(changeListener, times(1)).deviceStateChanged();
+    }
+
+    @Test
+    public void shouldChangeScreenStartAddressHighByte() throws Exception {
+        crtc.write(0, 12);
+
+        crtc.write(1, 0x00);
+        assertEquals(0x00, crtc.getStartAddress() >> 8);
+
+        crtc.write(1, 0x30);
+        assertEquals(0x30, crtc.getStartAddress() >> 8);
+
+        crtc.write(1, 0x6f);
+        assertEquals(0x6f, crtc.getStartAddress() >> 8);
+    }
+
+    @Test
+    public void changeScreenStartAddressHighByteShouldTriggerCallback() throws Exception {
+        crtc.write(0, 12);
+
+        crtc.write(1, 0x30);
+
+        verify(changeListener, times(1)).deviceStateChanged();
+    }
+
+    @Test
+    public void shouldChangeScreenStartAddressLowByte() throws Exception {
+        crtc.write(0, 13);
+
+        crtc.write(1, 0x00);
+        assertEquals(0x00, crtc.getStartAddress() & 0xff);
+
+        crtc.write(1, 0x11);
+        assertEquals(0x11, crtc.getStartAddress() & 0xff);
+
+        crtc.write(1, 0xff);
+        assertEquals(0xff, crtc.getStartAddress() & 0xff);
+    }
+
+    @Test
+    public void changeScreenStartAddressLowByteShouldTriggerCallback() throws Exception {
+        crtc.write(0, 13);
+
+        crtc.write(1, 0xff);
+
+        verify(changeListener, times(1)).deviceStateChanged();
+    }
+
+
+    @Test(expected = MemoryAccessException.class)
+    public void shouldThrowMemoryAccessExceptionIfPageOutOfRange() throws Exception {
+        crtc.write(0, 12);
+
+        crtc.write(1, 0x7f); // Page of text will extend beyond 0x7fff
+    }
+
+    @Test
+    public void readingStartAddressShouldDoNothing() throws Exception {
+        crtc.write(0, 12); // High byte
+
+        crtc.write(1, 0x03);
+        assertEquals(0, crtc.read(1));
+
+        crtc.write(1, 0x70);
+        assertEquals(0, crtc.read(1));
+
+
+        crtc.write(0, 13); // Low byte
+
+        crtc.write(1, 0xff);
+        assertEquals(0, crtc.read(1));
+
+        crtc.write(1, 0x0e);
+        assertEquals(0, crtc.read(1));
+    }
+
+
+    @Test
+    public void shouldChangeCursorPositionHighByte() throws Exception {
+        crtc.write(0, 14);   // Select register 14
+
+        crtc.write(1, 0x73); // Set high cursor byte to $73
+        assertEquals(0x73, crtc.getCursorPosition() >> 8);
+
+        crtc.write(1, 0x3f);
+        assertEquals(0x3f, crtc.getCursorPosition() >> 8);
+
+        crtc.write(1, 0x7f);
+        assertEquals(0x7f, crtc.getCursorPosition() >> 8);
+    }
+
+
+    @Test
+    public void shouldBeAbleToReadCursorPositionHighByte() throws Exception {
+        crtc.write(0, 14);
+
+        crtc.write(1, 0x3f);
+        assertEquals(0x3f, crtc.read(1));
+
+        crtc.write(1, 0x70);
+        assertEquals(0x70, crtc.read(1));
+    }
+
+    @Test
+    public void changeCursorPositionHighByteShouldTriggerCallback() throws Exception {
+        crtc.write(0, 14);
+
+        crtc.write(1, 0x73);
+
+        verify(changeListener, times(1)).deviceStateChanged();
+    }
+
+
+    @Test
+    public void shouldChangeCursorPositionLowByte() throws Exception {
+        crtc.write(0, 15);   // Select register 15
+
+        crtc.write(1, 0x00); // Set low cursor byte to $00
+        assertEquals(0x00, crtc.getCursorPosition() & 0xff);
+
+        crtc.write(1, 0x1f); // Set low cursor byte to $1f
+        assertEquals(0x1f, crtc.getCursorPosition() & 0xff);
+
+        crtc.write(1, 0xff); // Set low cursor byte to $ff
+        assertEquals(0xff, crtc.getCursorPosition() & 0xff);
+    }
+
+    @Test
+    public void shouldBeAbleToReadCursorPositionLowByte() throws Exception {
+        crtc.write(0, 15);
+
+        crtc.write(1, 0x00);
+        assertEquals(0x00, crtc.read(1));
+
+        crtc.write(1, 0x1f);
+        assertEquals(0x1f, crtc.read(1));
+
+        crtc.write(1, 0xff);
+        assertEquals(0xff, crtc.read(1));
+    }
+
+
+    @Test
+    public void changeCursorPositionLowByteShouldTriggerCallback() throws Exception {
+        crtc.write(0, 15);
+
+        crtc.write(1, 0x01);
+
+        verify(changeListener, times(1)).deviceStateChanged();
+    }
+
+    @Test(expected = MemoryAccessException.class)
+    public void shouldThrowMemoryAccessExceptionIfCursorGoesOutOfRange() throws Exception {
+        crtc.write(0, 14);   // Select register 14
+        crtc.write(1, 0x80); // Can't position cursor
+    }
+
+}