From: "John Herbster" <johnh@petronworld.com>
Subject: Re: Set8087CW and floating point
Date: 19 Nov 1999 00:00:00 GMT
Message-ID: <813ni3$piv18@forums.borland.com>
References: <811ij4$9d17@forums.borland.com> <812clp$gr92@forums.borland.com> <8136op$lq19@forums.borland.com>
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Here is a little routine that I use for getting last and changing the
control word:

function SetX87CW (NewCW: Word): word;
{ returns old and sets new FPU control word. }
asm {Part of this copied from D5 System.pas.}
  FNCLEX  // Don't raise pending exceptions enabled by the new flags.
  MOV     Default8087CW,AX // Copy new value to location in System unit.
  FStCW   [Result]         // Copy old value for returning to caller.
  FLDCW   Default8087CW    // Change the X87 control word here.
end;

You can use it like this:

Var Sav87CW: word;
...
Sav87CW := SetX87CW (<NewCW>);
... your special work ...
SetX87CW (Sav87CW);