[GHC] #7289: Mingw FPU init not Windows compatible.

[GHC]

#7289: Mingw FPU init not Windows compatible.
--------------------------+-------------------------------------------------
 Reporter:  Lennart       |          Owner:                
     Type:  bug           |         Status:  new           
 Priority:  normal        |      Component:  Runtime System
  Version:  7.2.2         |       Keywords:                
       Os:  Windows       |   Architecture:  x86           
  Failure:  None/Unknown  |       Testcase:                
Blockedby:                |       Blocking:                
  Related:                |  
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 Mingw initializes the FPU top 80 bit precision instead of MSVC's 53 bits
 (which is the standard).  I suggest ghc linking on Windows should be
 changed to that it uses 53 bits instead.  This will make programs more
 Windows compatible (and possibly faster).

 Here's a comment from Mingw's Float.h:

 /*
 MSVCRT.dll _fpreset initializes the control register to 0x27f,
 the status register to zero and the tag word to 0FFFFh.
 This differs from asm instruction finit/fninit which set control
 word to 0x37f (64 bit mantissa precison rather than 53 bit).
 By default, the mingw version of _fpreset sets fp control as
 per fninit. To use the MSVCRT.dll _fpreset, include CRT_fp8.o when
 building your application.
 */

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7289>
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