LINE.NEC is a short (1006 bytes  with REM lines and the demo removed)    program that enables the hidden LINE
 function in the NEC PC-8201.  After
 LINE.NEC is loaded and run, the PC-8201 will respond to LINE commands in
 exactly the same syntax as the Model    100. Thus, LINE(x1,y1)-(x2,y2) draws a  line between those points
 (x max=239, y max = 63; exceeding       either limit gives a FC Error.) If you
 add  ,0 after the close of the second
 parenthesis, you get a line "undrawn"   between the two points (i.e., a string
 of blanked pixels.)  If you add  ,1,B   as a suffix, you get an outline box
 whose corners are  x1,y1 upper left,    x2,y2 lower right.  Suffix  ,0,B
 "undraws" the same outline box.
  Suffix  1,BF draws a solid box, and    0,BF undraws one.

        Lines 45 and 46 of the program are a simple demo that the program has
done its thing.  They aren't needed for any other purpose.

        Once loaded and run, the LINE    syntax remains enabled even if you KILL the program; at least, it remains
 until something else gets POKE'd into
 any memory location from 62139 to       62335.

        For real compactness, you can create a machine language version of
 the program that's only 202 bytes long. After loading and running LINE.NEC, and seeing the demo work, go into BASIC
and type:

        BSAVE "LINE", 62139!,197

Your directory will now show LINE.CO as a file.  In order to be sure it runs
 correctly, you need to POKE 4 values
(or use LINE.LDR in this section; see       below), thus: 
        POKE 65215,207: POKE 65216,240:         POKE 64082,187: POKE 64083,242
Now, placing the cursor over LINE.CO and ENTERing will blank the screen for a
 few seconds, after which the menu will be restored, but you will have re-enabled the LINE function.

If you download LINE.LDR, which is another 81 bytes, you can leave that
 and LINE.CO in memory; together they consume less than 300 bytes.

                Robinson Markel
                72456,3604