[Issue 15334] New: OS X core.time ticksPerSecond calculation is incorrect

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=15334

          Issue ID: 15334
           Summary: OS X core.time ticksPerSecond calculation is incorrect
           Product: D
           Version: D2
          Hardware: All
                OS: Mac OS X
            Status: NEW
          Severity: regression
          Priority: P1
         Component: druntime
          Assignee: nobody at puremagic.com
          Reporter: gorox at comcast.net

The _d_initMonoTime() version(OSX) calculation for ticksPerSecond is using a
flipped mach_timebase_info ratio numer/denom when it should be denom/numer. 
Fortunately (or unfortunately depending on your point of view) it doesn't show
up as a problem on Intel OS X Macs because numer and denom are both 1.

On an iOS iPhone, wrong results would be produced because numer = 125 and denom
= 3.

The wrong calculation shows up here:

https://github.com/D-Programming-Language/druntime/blob/master/src/core/time.d#L2639

This is a regression because the correct calculation shows up in the deprecated
struct TickDuration here:

https://github.com/D-Programming-Language/druntime/blob/master/src/core/time.d#L2954

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