Created a target and a library for the Commander X16 prototype computer.

libsrc/cx16/clrscr.s

@@ -0,0 +1,26 @@
+;
+; 2019-09-22, Greg King
+;
+; void clrscr (void);
+; /* Clear the screen. */
+;
+
+        .export         _clrscr
+
+        .import         CHROUT
+
+        .include        "cx16.inc"
+
+
+; An internal Kernal function can't be used because it might be moved in future
+; revisions.  Use an official function; but, make sure that it prints
+; to the screen.
+
+_clrscr:
+        ldy     OUT_DEV         ; Save current output device
+        ldx     #$03            ; Screen device
+        stx     OUT_DEV
+        lda     #$93
+        jsr     CHROUT          ; Print clear-screen character
+        sty     OUT_DEV         ; Restore output device
+        rts