Set87ControlWord Procedure
Sets the 80x87 Control Word.

Unit
QESBPCSMath

Declaration
Procedure Set87ControlWord(const ControlWord: TESBBitList);

Description
15-12 Reserved

On 8087/80287 12 was Infinity Control

0 Projective

1 Affine

11-10 Rounding Control

00 Round to nearest even

01 Round Down

10 Round Up

11 Chop - Truncate towards Zero

9-8 Precision Control

00 24 bits Single Precision

01 Reserved

10 53 bits Double Precision

11 64 bits Extended Precision (Default)

7-6 Reserved

On 8087 7 was Interrupt Enable Mask

5 Precesion Exception Mask

4 Underflow Exception Mask

3 Overflow Exception Mask

2 Zero Divide Exception Mask

1 Denormalised Operand Exception Mask

0 Invalid Operation Exception Mask

Implementation

procedure Set87ControlWord (const ControlWord: TESBBitList);
var
     Temp: Word;
asm
	mov   	[Temp], ax    // Move Control Word into Memory location
	fldcw 	[Temp] 		// Load '87 Control Word
End;


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