Waterloo Structured BASIC was developed at the University of Waterloo in Ontario, Canada. and is an add on for the standard BASIC that comes on the PET and Vic 20 Commodore computers. This page will concentrate on two versions, the Vic 20 version that came as an autostart cart and a new version made from this cart that is presented as an image of an autostart cart for the Commodore 64 computer.

The Vic 20 version has been imaged and is available for download from archives such as zimmers. As far as I have been able to find out this cart was only made in small numbers and only available in Canada. More information can be found here.

The Commodore 64 was ported from the Vic 20 version. To do this the Vic 20 version was disassembled, all internal address references were resolved, all the external address references were changed where needed, the startup message was edited to reflect the changed status and the autostart incantation was changed to the Commodore 64 form. The whole thing was then relocated to the Commodore 64 cart space and reassembled.

The whole process took a couple of iterations. Not all the internal addresses were resolved on the first try and a couple of calls to the Vic kernal were not to known routine entry points so the equivalent points had to be found in the Commodore 64 kernal. Once this was done a few trivial test programs that use the Waterloo Structured BASIC commands were tested and performed as expected.

Just over half the 8K cart space is used, a little more than the Vic 20 version which just fitted into 4K. Most of the extra bytes are taken up by the longer sign on message.

The image can be downloaded here.