OK, I've investigated further now and poor man's debugging (e.g. printing the occuring values) showed that in the DiscardBytes() function of RDRAND, the n values all over the place jumps, from 10000 (as correctly initialized) to 4280436152 in the second iteration to 4265895008 in the third one and so on, instead of the expected decrease by 64 every round (the count variable is set correctly).
This of course results in an infinite loop and thus in the test program not finishing. I don't know how to fix this though, because I don't understand why it does this in the first place. BR JPM Am 06.09.2016 um 15:37 schrieb Jeffrey Walton: > > I've run the latest version of master and constexpr branches > against each other and measured the time of "cryptopp.exe v" using > Powershell's Measure-Command on my i7-6500U (slight background noise). > > Here are the results: > > Configuration > constexpr Time > master Time > x86 Debug > 4s 57ms > 4s 344ms > x64 Debug > 9s 810ms > 9s 245ms > x86 Release > doesn't finish!? (RDRAND / RDSEED) doesn't finish!? (RDRAND / > RDSEED) > x64 Release > 1s 759ms > 1s 735ms > > All the times should be taken +-500ms for significance. > > OK, so it looks like Windows completes about 300 ms faster in Debug > builds. I'm guessing we are moving in the right direction. > > Yes, I'd be interested in learning what is broken with RDRAND and > RDSEED. The last change to it was a simplification of the logic at > http://github.com/weidai11/cryptopp/commit/0deae2c97421bbd6050af30dde7ac21951ddaf9f > . Maybe an illegal instruction??? > > Jeff > -- > -- > You received this message because you are subscribed to the "Crypto++ > Users" Google Group. > To unsubscribe, send an email to > cryptopp-users-unsubscr...@googlegroups.com. > More information about Crypto++ and this group is available at > http://www.cryptopp.com. > --- > You received this message because you are subscribed to the Google > Groups "Crypto++ Users" group. > To unsubscribe from this group and stop receiving emails from it, send > an email to cryptopp-users+unsubscr...@googlegroups.com > <mailto:cryptopp-users+unsubscr...@googlegroups.com>. > For more options, visit https://groups.google.com/d/optout. -- -- You received this message because you are subscribed to the "Crypto++ Users" Google Group. To unsubscribe, send an email to cryptopp-users-unsubscr...@googlegroups.com. More information about Crypto++ and this group is available at http://www.cryptopp.com. --- You received this message because you are subscribed to the Google Groups "Crypto++ Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to cryptopp-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
