The DigiTek VECTRON is one of a pair of fictional display devices written for use with <a href="https://monolith.cesque.com/qcpu">qcpu</a>. The VECTRON uses 2-color vector graphics, and has a square display. Since qcpu interacts with external devices with the <code>SYS</code> system call opcode, the VECTRON exposes 5 different syscalls in order to control it:

<code>SYS 21</code> DRAW LINE: disable DRAWING MODE, move cursor to (x, y), enable DRAWING MODE, move cursor to (a, b).

<code>SYS 22</code> LIFT AND MOVE: disable DRAWING MODE, move cursor to (x, y), enable DRAWING MODE.

<code>SYS 23</code> CONTINUE LINE: move cursor to (x, y).

<code>SYS 24</code> SET BRIGHTNESS: dim DRAWING MODE color to (x), where 0 is minimum brightness (off) and 65535 is full brightness.

<code>SYS 25</code> SET COLOR: change DRAWING MODE color to (x), where 0 is white and 1 is red.

<li><code>SYS 21</code> DRAW LINE: disable DRAWING MODE, move cursor to (x, y), enable DRAWING MODE, move cursor to (a, b).</li><li><code>SYS 22</code> LIFT AND MOVE: disable DRAWING MODE, move cursor to (x, y), enable DRAWING MODE.</li><li><code>SYS 23</code> CONTINUE LINE: move cursor to (x, y).</li><li><code>SYS 24</code> SET BRIGHTNESS: dim DRAWING MODE color to (x), where 0 is minimum brightness (off) and 65535 is full brightness.</li><li><code>SYS 25</code> SET COLOR: change DRAWING MODE color to (x), where 0 is white and 1 is red.</li>

The coördinates provided to these calls map the square screen from top left (0, 0) to bottom right (65535, 65535).

N.B. the CONTINUE LINE syscall is so named because the other syscalls do not allow the drawing mode to be left disabled after their use, so the CONTINUE LINE syscall will always draw a line to the screen. Also, the use of values greater than 1 as the argument for the SET COLOR syscall is technically undefined, but implementations would be smart to treat this as if the argument was 1 regardless.

An example program written for the DigiTek VECTRON is shown below: