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Message: 7145

Author: ian.rushforth

Date: 19/09/2017

Subject: Re: Relocatable patches (using RoomNo as an example)

 

Andrew wrote:

In the unpatched game-engines, the free space is as follows:

MM48
----
* #934C-9CFF (#9B4 bytes) contain assembly-code which can safely be overwritten.

Note that the 'high' end of that range of addresses is used by the program for the stack (starting at #9CFE-9CFF), so any patches which are placed at that end of the above range may get overwritten during run-time.

******

Another random correction - in the TECHNICA for the Advnaced MM/JSW Trainer:

"the room-setup patch-vector must select Bank 1 (for Rooms 0-31) as the one that is paged into #C000-FFFF before it alters the room-datum, and must switch back to Bank 0 afterwards. It does so by writing %00001BBB (where BBB are the bank to page in) to the hardware-switch at I/O address #7FFD."

The element in bold should read %00010BBB .

 

 

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