Before you stands a huge mansion and inside, it is rumoured, a fortune in gold. Do you have it in you to find this treasure? Are you brave or clever enough? What's more, do you think you can come out alive?
House of Secrets is a traditional text adventure written in Basic but with several machine code routines to provide a split screen and a fast response time. If you have played adventures before you will be familiar with the method of play but details are included in the introduction. The game has the facility to save partially completed adventures to tape or disk and the overall effect matches that of many commercially available adventures.
As far as the programming goes, locations 1536-1569 contain a new display list to split the screen between page 124 for the top and the usual screen memory (S) for the bottom.
USR(1710) clears page 124.
USR(1570) writes to page 124.
USR(1593,X,S) adjusts the size of the top screen section to display exactly the number of lines (X) written, by changing the display list in page 6.
USR(CH,ADR of $,ADR of character to be found, length of $ to search) searches for a particular character in a string. The value of the variable CH is 1738.
USR(DE,ADR(NOUN$), N, length of NOUN$) checks that the noun is valid. The verb routine is similar. The variable DE is the ADRess of DE$ and N is the ADRess of N$.
The program uses no arrays. The master string, M$ contains the location number, possible exits (6), and the objects present for each location. It is updated after leaving a location and is the only information that is needed to be saved on the SAVE GAME routine. ME$ records the location you are in and the objects being carried. LOC$ records the present location and its contents.
No help responses are given in order to save space, but it would be a simple matter to add appropriate responses depending on the location. The adventure is moderately difficult even after typing it in and getting clues from the listing.
Be careful with the DATA statements and make sure you SAVE a copy before you RUN it. Remember also that you must have at least 32K memory.
If you would prefer to play House of Secrets without looking at the listing
or you find the prospect of all that typing too daunting, I can offer copies on tape or disk by post. Send £2.50 for a cassette copy or £3.50 for a disk copy to David Blease, 31, Melcombe Avenue, Weymouth, Dorset. Tel 0305 71230. Please ensure that your name and address are included and are legible.