Probabilistic testing would very likely have caught this problem as well, for much cheaper.
#INTEL BURN TEST GFLOP SIMULATOR#
Realistically, you'd need to run validation in a hardware simulator or somehow do validation over a network to avoid wasting a bad batch. The numbers here are all quite generous and we're only validating a single instruction. Amazingly, that's not as infeasible as I imagined: at $500 a pop (rough guess b/c pentiums weren't sold directly to consumers), that's only $355M, which is less than the $475M loss Intel recorded for the bug. If you're willing to run validation for a month straight, you would need 355,840 processors running in parallel. Let's say that the reference implementation and associated checks is 10 instructions long so you can check 20 million numbers per second. Exhaustive testing would have to cover all combinations of A and B, hence the search space is four billion squared or about 1.84e19.Ī pentium at the time could do ~200 MIPS. The intel floating point bug was in the FDIV operation, which implemented floating point division. This can happen very easily when subtracting.
5" it has to do with calculation results where the first digit that can't be stored is a 1 and all remaining digits are zero. The frequency at which this rule is required is nothing to do with "numbers that end exactly in. So, round to nearest even is applied which in this case means round down. Always rounding up or always rounding down would be a "bad idea". (exponent omitted because it doesn't matter) then the 25th digit is a one, the remaining digits are zero, and you have to round up or down with no reason to prefer either. For instance, if the float result of some calculation is (in binary): If you do a floating-point math calculation that gives a result which cannot be represented exactly in a float/double then the round-to-nearest-even rule is applied. But that is not the only time that it applies. The round-to-nearest even rule is most intuitively visible to humans when dealing with numbers like 5.5 or 6.5. It turns out there is no bias, there are exactly 5 numbers less than 0.5 and exactly 5 numbers greater or equal. So, rounding/truncating/whatever all decimal numbers to just one decimal digit you obtain the numbers (that's why you don't have 10, because it would be the 0 of the next integer). To go back to your example: let's say you want to round to the nearest integer, what you need is a fair way to round the decimals to either 0 or 1. At that point it doesn't matter if you're rounding integers or not (you're just looking at the digit in the position you fixed earlier). more precision, will be overshadowed by coarsest power of ten you're rounding to). It's true you don't have to round to an integer, but you have to round to some fixed power of ten (rounding at smaller powers of ten, i.e. I don't know the specifics of the IEEE standard, so let's talk about real numbers. So the tie-breaking rule is only applicable when your data ends in exactly the digit "5". To round numbers, in a certain base, you do it by looking at the digits of said numbers (rounding is inherently a representation issue, and numbers are represented by their digits). That rounding only occurs when dealing with numbers, not digits Are you interested in promoting your own content? STOP! Read this first.For posting job listings, please visit /r/forhire or /r/jobbit.Do you have something funny to share with fellow programmers? Please take it to /r/ProgrammerHumor/.Do you have a question? Check out /r/learnprogramming, /r/cscareerquestions, or Stack Overflow.Direct links to app demos (unrelated to programming) will be removed.
#INTEL BURN TEST GFLOP CODE#
If there is no code in your link, it probably doesn't belong here. Just because it has a computer in it doesn't make it programming.
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