unit Safe8087CWUtils;

interface

procedure SafeSet8087CW(ANewCW: Word); stdcall; export;
procedure SafeSet8087CWEx(ANewCW: Word); register;
function SafeGet8087CW :Word; stdcall; export;
function SafeGet8087CWEx :Word; register;

implementation

function SafeGet8087CW :Word; stdcall; export;
begin
  Result := SafeGet8087CWEx();
end;

function SafeGet8087CWEx :Word; register;
var
  localCurrentCW: Word;
asm
  FNSTCW localCurrentCW         // Store current FPU control word in to localCurrentCW
  MOV AX, localCurrentCW        // Copy value in localCurrentCW to AX register for result
end;

procedure SafeSet8087CW(ANewCW: Word);
begin
  SafeSet8087CWEx(ANewCW);
end;

procedure SafeSet8087CWEx(ANewCW: Word);
var
  localNewCW: Word;
asm
  MOV localNewCW, ANewCW        // Copy ANewCW (in AX) to localNewCW so we can use localNewCW with FLDCW which requires a reference to memory
  FNCLEX                        // don't raise pending exceptions enabled by the new flags
  FLDCW   localNewCW            // Load FPU Control Word with value in localNewCW
end;

exports
  SafeSet8087CW, SafeGet8087CW;

end.