Laser 3000 BASIC

When my Laser 3000 is first turned on, the following message appears on the screen:

    (C) COPYRIGHT V.T. 1984

The ads say that this BASIC takes 32K, but as yet I've only seen ROM code in the normal area from $D000-$FFFF (12K), a small amount of code following $C800, and some code for internal expansion devices for slots 1 and 3 (normally for printer and 80 column card). The rest must be hiding outside the 64K address range, which could explain some of the sluggish feel to the machine (compared to the Apple ][). On the other hand, the ROM code I do see seems to have some debugging info in it, so either Microsoft was programming up to their usual "high standards" with regards to efficiency, or the BASIC was never really finished.

Additional Commands

The Laser 3000's BASIC has some commands that the Apple ][ doesn't have:

Text Commands
Graphics Commands
Sound Commands
Other Commands

Specific Bugs

The XDRAW command does not work as on an Apple ][. On a real Apple, XDRAW will plot the given shape table image, XOR'ed with the background. This allows one to easily plot and then remove a shape without disturbing the background. This is also good for some visual effects. On the Laser 3000, however, XDRAW merely plots the shape in black. Not terrifically useful.

General Bugs

Keywords that are normally found in AppleSoft BASIC will be recognized when typed in upper or lower case, but the keywords from the extended BASIC commands must be typed in UPPER case. For example:

     10 text normal,black,black

will give a syntax error when the program is executed. Listing it reveals:

     10 TEXT NORMAL ,black,black

showing us that the AppleSoft keywords "TEXT" and "NORMAL" were recognized. Had this line been typed in upper case, there wouldn't have been a problem.

Other Things Of Note

BASIC programs are stored, by default, starting at location 6144 ($1800), not at 2048 ($0800) as on the Apple ][. This is because the first 80-column text screen resides in locations 4096-6143 ($1000-$17FF). This leaves only 2K for your BASIC program before it starts overwriting the memory of high resolution graphics page 1. Or, to stress the importance of this limitation, any BASIC program over 2K in length will be destroyed upon issuance of the "HGR" command. Has this scared you enough?

The processing speed of the machine seems to be affected by the text or graphics mode the machine is in. Using the following program:

	20 FOR X = 1 TO 50000: NEXT

the Laser 3000 takes 57 seconds to complete the loop when in 40-column or high-res graphics mode, but only 28.5 seconds when in 80-column or double high-res mode. My Apple //c takes 56 seconds to run the same program, no matter what text or graphics mode it's in. I don't know if it's possible to decouple the processor speed and the text/graphics mode. It's possible that the dot clock and the processor clock are linked in hardware.

[Laser 3000 Home] [Hrothgar's Cool Old Junk Page] 1998-05-15