Thread: Snakes!
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Old 01 November 2011, 01:36   #71
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Originally Posted by clenched View Post
Give me half an hour. If there are no intervening posts then it will be here.
Thanks for your effort on this, mate.

Originally Posted by clenched View Post
Prowler - Here are four changes for you to have a look at. Made with wip6. Original byte on left, new on right.

00005DAA: FA FF Look closely at the last S on the snakes logo when first booting. See the two lighter pixels? This change is the new data after repainting.
Yes, I had noticed that. Thanks for fixing it!

Originally Posted by clenched View Post
00007529: DC 5C Fix keyboard selector that caused selector to spring back and also some wrong data to be blitted. Arrived at by comparing DEMO code to WIP code.
Thanks again!

Originally Posted by clenched View Post
0000C268: 05 07 Unscramble opening picture. Arrived at by comparing DEMO data to WIP data.
I can confirm this change, which fixes the bad sector I mentioned in my last but one post, so this fix appears in the WIP7 image I have attached below.

Originally Posted by clenched View Post
00051ED8: 30 08 This is just hack of level 15 that replaces the blue mine with another harmless tile. I did transplant the entire level 15 data into the DEMO (300 bytes 20*15 tiles) and it locked up too. So there is a possibility that bug could have always been there.
Good work!

Originally Posted by clenched View Post
So #1 is a guess but reasonable I think. #2,#3 99% sure. #4 doubtful but better than it was.
I agree with your reasoning for changes #1 and #2, and I can confirm change #3 fixes a bad sector which I recovered earlier this evening.

Because change #4 comprises a 3-bit change, I don't think it will reverse disk corruption of the type I am seeing on this disk, so your theory that this bug could always have been there may be a good one.

Apart from change #3, which is already included in WIP7, and fixes the title screen at last, I would first like to test the effect of introducing these other changes on the status of the 8 remaining bad sectors before I include them in the next WIP.
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Last edited by prowler; 01 November 2011 at 22:32. Reason: bits and bytes...
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