Added proc to write characters to terminal.

kernel.nim

@@ -32,8 +32,21 @@ var
   terminalRow, terminalColumn = 0
   terminalColour = vgaEntryColour(VGA_Colour.lightGrey, VGA_Colour.black)
 
+proc terminalWriteAtPoint(writeChar: char, colour: uint8, xPos: int, yPos: int) =
+  let index = terminalBufferBaseAddress + (yPos * vgaWidth + xPos)
+  cast[ptr uint16](index)[] = vgaEntry(' ', terminalColour) # Write directly to display memory
+
 proc terminalInitialize() =
   for y in 0..<vgaWidth:
     for x in 0..<vgaHeight:
-      let index = terminalBufferBaseAddress + (y * vgaWidth + x)
-      cast[ptr uint16](index)[] = vgaEntry(' ', terminalColour) # Write directly to display memory
+      terminalWriteAtPoint(' ', terminalColour, x, y)
+
+proc setTerminalColour(newColour: uint8) =
+  terminalColour = newColour
+
+proc terminalWriteChar(writeChar: char) =
+  terminalWriteAtPoint(writeChar, terminalColour, terminalColumn, terminalRow)
+  inc(terminalColumn)
+  inc(terminalRow)
+  if(terminalColumn == vgaWidth): terminalColumn = 0
+  if(terminalRow == vgaHeight): terminalRow = 0