null argument to support print w/o newline|new EMIT fn for BASIC

src/net/torvald/tsvm/GraphicsJSR223Delegate.kt

@@ -71,6 +71,8 @@ class GraphicsJSR223Delegate(val vm: VM) {
     fun putSymbol(char: Byte) {
         getFirstGPU()?.let {
             val (cx, cy) = it.getCursorPos()
+
+
             it.putChar(cx, cy, char)
             it.setCursorPos(cx + 1, cy)
         }

src/net/torvald/tsvm/peripheral/GlassTty.kt

@@ -34,13 +34,7 @@ abstract class GlassTty(val TEXT_ROWS: Int, val TEXT_COLS: Int) {
     abstract fun putChar(x: Int, y: Int, text: Byte, foreColour: Byte = ttyFore.toByte(), backColour: Byte = ttyBack.toByte())
 
     fun writeOut(char: Byte) {
-        // deal with y-axis out-of-bounds
-        var (cx, cy) = getCursorPos()
-        if (cy >= TEXT_ROWS) {
-            scrollUp(cy - TEXT_ROWS + 1)
-            setCursorPos(cx, TEXT_ROWS - 1)
-            cy = TEXT_ROWS - 1
-        }
+        val (cx, cy) = getCursorPos()
 
         val printable = acceptChar(char) // this function processes the escape codes and CRLFs
 

src/net/torvald/tsvm/peripheral/GraphicsAdapter.kt

@@ -69,11 +69,7 @@ class GraphicsAdapter(val vm: VM, val lcdMode: Boolean = false, lcdInvert: Boole
         set(value) { spriteAndTextArea.setShort(memTextCursorPosOffset, value.toShort()) }
 
     override fun getCursorPos() = rawCursorPos % TEXT_COLS to rawCursorPos / TEXT_COLS
-    /**
-     * Think of it as a real paper tty;
-     * setCursorPos must "wrap" the cursor properly when x-value goes out of screen bound.
-     * For y-value, only when y < 0, set y to zero and don't care about the y-value goes out of bound.
-     */
+
     override fun setCursorPos(x: Int, y: Int) {
         var newx = x
         var newy = y
@@ -89,6 +85,11 @@ class GraphicsAdapter(val vm: VM, val lcdMode: Boolean = false, lcdInvert: Boole
         if (newy < 0) {
             newy = 0 // DON'T SCROLL when cursor goes ABOVE the screen
         }
+        else if (newy >= TEXT_ROWS) {
+            scrollUp(newy - TEXT_ROWS + 1)
+            setCursorPos(newy, TEXT_ROWS - 1)
+            newy = TEXT_ROWS - 1
+        }
 
         rawCursorPos = toTtyTextOffset(newx, newy)
     }