Hi Greg, All good. I think you described it fine. The question I had was more on what the big picture was. Why do it at all?
And yes, there’d be a way to manipulate the bits to manually construct it, but in most languages, that’d be pretty ugly anyway. Regards, Greg Dr Greg Low 1300SQLSQL (1300 775 775) office | +61 419201410 mobile SQL Down Under | Web: https://sqldownunder.com<https://sqldownunder.com/> | About Greg: https://about.me/greg.low From: Greg Keogh <gfke...@gmail.com> Sent: Tuesday, 5 July 2022 8:58 AM To: Dr Greg Low <g...@sqldownunder.com> Cc: ozDotNet <ozdotnet@ozdotnet.com> Subject: Re: 53-bit double I might have missed it earlier Greg but was the actual problem that this helps with? I was intrigued by the underlying problem. I didn't express myself clearly originally. I was trying to convert a 64-bit random integer into a double and guarantee that all possible 2^53 floating values in the range 0 to 1 could result. Someone suggested that weird bit of earlier incomprehensible code, but it turns out a simple shift-and-multiply does that trick. There are lots of modern PRNGs that generate 64-bits, like the xoroshift** that is being used in the latest Random class. But how do you convert 64-bits "perfectly" into doubles? I finally confirmed a correct way. I'm still wondering if there is a way of manually constructing an IEEE 754 number from the raw bits, but it makes my head hurt. Cheers, GK
