Intel 80287, 80286 manual FLD, FBLD1 FILD2 FST,FSTP, Fbstp FIST, Fistp, Fprem, Fsqrt, Ftst ±O Fchs

OVERVIEW OF NUMERIC PROCESSING

handler could determine which element had been accessed, since the operand address field of the exception pointers would point to the NaN, and the NaN would contain the index number of the array element.

Table 1-10. Zero Operands and Results

Operation/OperandsResultOperation/ OperandsResult

FLD, FBLD(1)
+0	+0
-0	-0
FILD(2)
+0	+0
FST,FSTP
+0	+0
-0	-0
+X(3)	+0
-X(3)	-0
FBSTP
+0	+0
-0	-0
FIST, FISTP
+0	+0
-0	+0
+X(4)	+0
_X(4)	+0
Addition
+0 plus +0	+0
-0 plus -0	-0
+0 plus -0, -0 plus +0	'0)
-X plus +X, +X plus -X	(5
	'0)
	(5
±O plus ±X, ±X plus ±O	tXIB)
Subtraction
+0 minus -0	+0
-0 minus +0	-0
+0 minus +0, -0 minus -0	'0)
+X minus +X, -X minus -X	(5
	'0)
	(5
±O minus ±X, ±X minus ±O	tXI.)
Multiplication
+0·+0, -0·-0	+0
+0·-0, -0·+0	-0
+O·+X,+X·+O	+0
+Oo-X,-X.+O	-0
-0·+X, +X·-0	-0
-0· -X, -X·-O	+0
+X·+Y,-x·-y	+0, u(ujcrf:ov·.;!7~
+Xe-Y,-X·+Y	-0, underflow(7)

NOTES:

Division ±o -;.- ±o ±X -;.- ±o

+0 -;.- +X, -0 -;.- -X +0-;.- -X, -0-;.- +X -X -;.- -V, +X -;.- +Y -X-;.- +Y, +X-;.--Y

FPREM

±O rem ±O ±X rem ±O

+0 rem +X, +0 rem -X -0 rem +X, -0 rem -X +X rem +Y, +X rem -Y -X rem -V, -X rem +Y

FSQRT -0

+0

Compare ±O: +X ±o: ±o ±O: -X

FTST ±O

FCHS

+0 -0

FABS ±O F2XM1

+0 -0

FRNDINT

+0 -0

FXTRACT +0

-0

Invalid operation Zerodivide

+0 -0

+0, underflowlB) -0, underflowlB)

Invalid operation Invalid operation

+0 -0

+0(9) -0(9)

-0 +0

A<B

A=B

A>B

Zero

-0 +0

+0

+0 -0

+0 -0

Both +0

Both -0

I

(1)Arithmetic and compare operations with real memory operands interpret the memory operand signs in the same way.

(2)Arithmetic and compare operations with binary integers interpret the integer sign in the same manner.

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