freepascal.compiler/rtl/i386/mathu.inc

{
    $Id$
    This file is part of the Free Pascal run time library.
    Copyright (c) 1999-2003 by Florian Klaempfl
    member of the Free Pascal development team

    See the file COPYING.FPC, included in this distribution,
    for details about the copyright.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

**********************************************************************}

{$define FPC_MATH_HAS_ARCTAN2}
function arctan2(y,x : float) : float;assembler;
  asm
     fldt y
     fldt x
     fpatan
     fwait
  end;


function GetRoundMode: TFPURoundingMode;
begin
  Result := TFPURoundingMode((Get8087CW shr 10) and 3);
end;

function SetRoundMode(const RoundMode: TFPURoundingMode): TFPURoundingMode;
var
  CtlWord: Word;
begin
  CtlWord := Get8087CW;
  Set8087CW((CtlWord and $F3FF) or (Ord(RoundMode) shl 10));
  Result := TFPURoundingMode((CtlWord shr 10) and 3);
end;

function GetPrecisionMode: TFPUPrecisionMode;
begin
  Result := TFPUPrecisionMode((Get8087CW shr 8) and 3);
end;

function SetPrecisionMode(const Precision: TFPUPrecisionMode): TFPUPrecisionMode;
var
  CtlWord: Word;
begin
  CtlWord := Get8087CW;
  Set8087CW((CtlWord and $FCFF) or (Ord(Precision) shl 8));
  Result := TFPUPrecisionMode((CtlWord shr 8) and 3);
end;

function GetExceptionMask: TFPUExceptionMask;
begin
  Result := TFPUExceptionMask(Get8087CW and $3F);
end;

function SetExceptionMask(const Mask: TFPUExceptionMask): TFPUExceptionMask;
var
  CtlWord: Word;
begin
  CtlWord := Get8087CW;
  Set8087CW( (CtlWord and $FFC0) or Byte(Longint(Mask)) );
  Result := TFPUExceptionMask(CtlWord and $3F);
end;

procedure ClearExceptions(RaisePending: Boolean);assembler;
asm
  cmpb $0,RaisePending
  je .Lclear
  fwait
.Lclear:
  fnclex
end;

{
  $Log$
  Revision 1.2  2003-10-26 15:58:05  florian
    * fixed arctan2 to handle x=0 correctly as well

  Revision 1.1  2003/04/24 09:16:31  florian
    * initial implementation with code from math.pp
}