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This question is about detecting and possibly correcting arithmetic errors in the CPU.

Consider any recent core iX Intel CPU. Suppose I wanted to multiply 8 times 7, in psuedo-code thusly,

mov 8 to AX

mul AX by 7

Then further suppose the ALU came up with 55 instead of 56. Would the CPU issue an error of some kind. If so, how? Fundamentally my question relates to errors in arithmetic, which because of cosmic rays and voltage blips are almost certain to occur. Is there any logic in the ALU/CPU to detect and possibly correct such errors?

The answer is important. At least tell me how to find the answer.

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http://www.intel.de/content/www/us/en/processors/architectures-software-developer-manuals.html

Error codes are described in Section 15.9.

Depending how important reliability is for you, you can use ECC, DDDC, memory mirroring, QPI in lockstep mode, or even use a complete lockstep system like the systems from NEC or Stratus.

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iliyapolak wrote:Where I can find information about random noise induced CPU and/or data bus related errors.>>>Cosmic particles, heat, and similar reasons can cause a large variety of possible errors in a complex system like a computer.>>>

Even simply clock frequency jitter which manifests itself as a miniscule phase shift(s) can change the value of the bitstream.

It is intersting how for example floating point calculation and memory reading/writing could be affected by such a erratic behaviour and what is the probability of stochastic noise induced bus errors.

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**ALU/CPU Error Detection**but at least it provides some information on how memory errors could be corrected.

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Sergey Kostrov wrote:

I found a small article about ECC on Wiki and please take a look: http://en.wikipedia.org/wiki/ECC_memory

It is not related to the original question

ALU/CPU Error Detectionbut at least it provides some information on how memory errors could be corrected.

Thanks for the link.It partly answers my other question also related to the statistical rate of the errors,

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