[MCPE-21790] Rs Nor Latches unstable Created: 06/May/17  Updated: 09/May/18  Resolved: 09/May/18

Status: Resolved
Project: Minecraft (Bedrock codebase)
Component/s: None
Affects Version/s: 1.1.0.9, 1.0.8.1
Fix Version/s: None

Type: Bug
Reporter: Brian Teague
Resolution: Cannot Reproduce Votes: 1
Labels: None

Attachments: Zip Archive 5TQAABmLAQA=.zip     Zip Archive 9QEAALHuAgA=.zip     PNG File IMG_0404.PNG     PNG File IMG_0405.PNG    
Confirmation Status: Unconfirmed
Platform: Phone - iOS - iPhone 6 Plus

 Description   

RS Nor latches will pulse in an infinite loop causing a 100% CPU spike when they receive the invalid state of R=1 and S=1. Trying to set S=1 R=0 will not break the infinite loop. You have to manually break the redstone on the RS Nor latch. This bug does not occur on the PC version of Minecraft.

As seen in the first attached image, if you flip the lever on the control wire which simultaneously powers R and S, the latch will glitch and loop infinitely causing a CPU spike to 100% usage. My phone will lag horribly.

This issue can also occur using only a Set pulse (using a lever, not a button or exact 1 tick pulse) which is a valid state for an RS Nor Latch or when chunks load on restarting the world.

I have had to replace all of my RS Nor latches with redstone repeater latches in order to make progress on my computer.

Second image for anyone interested:
Red wire - ALU
Yellow wire - Clock and initialization
Bottom left (under item bar) - 6 bit Program counter
Bottom right - Multiplexer to 64 lines of program memory (Harvard architecture)
Top right orange - 10 bit instruction decoder (4 bit opcode - 6 bit parameter)
Green - CPU control lines
Top orange - 16 bytes of 4 bit memory
Bottom left - 4 bytes of dual read registers
Top left green - Multiplexer for ram addressing



 Comments   
Comment by [Mojang] Mega_Spud (Jay Wells) [ 09/May/18 ]

Cleaning up old tickets: This ticket has not been updated recently (1 year+) so is being closed as Cannot Reproduce. If you feel this is still a valid issue then please comment, or create a new ticket following the Issue Guidelines.

Quick Links:
📓 Issue Guidelines – 💬 Community Support – 📧 Feedback – 📖 Game Wiki

Comment by Brian Teague [ 07/May/17 ]

World with the RS nor latch bug has been uploaded 5TQAABmLAQA=.zip
Also replaced images with higher resolution.

World with the computer is 9QEAALHuAgA= but all RS Nor latches have been removed from this world because of the issues they were causing.

Comment by [Mojang] Mega_Spud (Jay Wells) [ 06/May/17 ]

If you could upload a copy of the world it would be useful in testing out this bug further.

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