Hi, I wish to modify `Display.Mod' to accept 4-bit colour. Standard interface currently supports 1-bit colour only. PROCEDURE Dot*(col, x, y, mode: INTEGER); PROCEDURE ReplConst*(col, x, y, w, h, mode: INTEGER); PROCEDURE CopyPattern*(col, patadr, x, y, mode: INTEGER); PROCEDURE CopyBlock*(sx, sy, w, h, dx, dy, mode: INTEGER); PROCEDURE ReplPattern*(col, patadr, x, y, w, h, mode: INTEGER); I have a version of VID.v with 4-bit pixels and a 16 entry colour lookup table. So `col' parameter in the range {0..15} defines index into that table. Looking at the code, I realise each display line takes 128 bytes 1-bit. 4-bit it must be 4*128. While single word sets 1-bit colour of 32 pixels, and only 8 pixels of 4-bit colour, correct? I am generally seeking advice for the good starting point, also hwoto set up a test environment for quick tests turnaround? My idea was to make a standalone boot program accepting draw commands over serial. I may start with `ReplConst' (font rendering), and `ReplConst' (line drawing). I wonder how much of the original code I could reuse, just extending the loop count, and some 4-bit manipulation? Many thanks in advance. -- Tomas Kral <thomas.kral@email.cz>