Scor­pio News


July–September 1987 – Volume 1. Issue 3.

Page 36 of 67

If the jump instructions are present, the system size is checked to determine whether warm boot should be off ROM (standard system) or disk (non-standard system). In each case a small piece of code, to turn off the ROM board and jump to the correct entry point, is copied to an area of free RAM (0020h) and executed.

The soft switch can be used with any CPU card that has jump-on-reset hardware (e.g. Nascom 2) and a GM803 or GM853 EPROM card. The EPROM card must be configured to be paged in after a reset.

Individual users may wish to add other features to the soft switching mechanism, such as forced jumps to, say, BASIC or Naspen. This could be implemented in a similar fashion to that on the BBC Microcomputer. That is, check for any pressed keys and force jump accordingly, i.e. pressing ‘B’ at reset time will force BASIC to be loaded and executed.

Listing continued on page 41.

Page 36 of 67