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using Manic Miner and Jet Set Willy game engines
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Message: 7144
Author: ian.rushforth
Date: 15/09/2017
Subject: Re: Question about inserting patch vectors in JSW64
> and so pointing at the address #C100 will not execute the patch vector that is stored in the room data.
Sorry, that should have read: "and so if the patch vector points at the address #C100 in Bank 0, the program will not execute the patch which is stored in the room data in another data bank."
Here is my thinking on the matter of Patch Vector terminology:
- The 'Patch Vector Subroutine' is the four-byte subroutine that is CALLed from the Main Loop (or from the Room Setup Routine), which picks up a two-byte address stored within each room's data, and jumps to it;
- 'Patch Vector' is the term for the jump destination address, stored across two spare offset bytes within the room data for each room (i.e. the Patch Vector refers to the coordinates where the Patch for that room is located);
- A 'Patch' is a subroutine, located at the address that is pointed at by the 'Patch Vector' for the current room; the Patch is CALLed up from the Main Loop (or from the Room Setup Routine) via the 'Patch Vector Subroutine'.
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