Resource centre for ZX Spectrum games
using Manic Miner and Jet Set Willy game engines
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Manic Miner & Jet Set Willy Yahoo! Group
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Message: 7052
Author: ian.rushforth
Date: 13/02/2017
Subject: Re: wraparound / mm
Incidentally, I don't believe that any corruption would occur in JSW if the up/down room exit code is disabled to allow Willy to wrap up/down in this way.
That would be harmless, because the Screen Buffer Address look-up table at #8200-FF is immediately followed by the Rope Animation table at #8300-FF. The first 30 entries of which holds values of '00'.
So even if the 'Draw Willy' routine did extend beyond the valid range of the look-up table, no harm could come of an attempt by the program to overwrite addresses with a high byte of '00' - the start of the ROM!
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