Intel 80286 User Manual

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/Operands Result Operation/ Operands Result
FLD, FBLD(1)
Division
+0 +0
±o -;.- ±o
Invalid operation
-0 -0
±X -;.- ±o
Zerodivide
FILD(2)
+0 -;.- +X, -0 -;.- -X
+0
+0 +0
+0-;.- -X, -0-;.- +X
-0
FST,FSTP
-X -;.- -V, +X -;.- +Y +0, underflow
lB
)
+0 +0
-X-;.- +Y, +X-;.--Y
-0, underflow
lB
)
-0 -0
+X(3)
+0
FPREM
-X(3)
-0
±O rem ±O
Invalid operation
FBSTP ±X rem ±O Invalid operation
+0 +0
+0 rem +X, +0 rem -X
+0
-0
-0
-0 rem +X, -0 rem -X
-0
FIST, FISTP +X rem +Y, +X rem -Y
+0
(9
)
+0 +0
-X rem -V, -X rem +Y
-0
(9
)
-0
+0
+X(4)
+0
FSQRT
_X(4)
+0
-0
-0
+0 +0
Addition
+0 plus +0
+0
Compare
-0 plus -0
-0
±O: +X A<B
+0 plus -0, -0 plus +0
'0
(5
)
±o: ±o A=B
-X plus +X, +X plus -X
'0
(5
)
±O: -X
A>B
±O plus ±X, ±X plus ±O
tXIB)
FTST
Subtraction ±O Zero
+0 minus -0
+0
FCHS
-0 minus +0
-0
+0
-0
+0 minus +0, -0 minus -0
'0
(5
)
-0
+0
+X minus +X, -X minus -X
'0
(5
)
FABS
±O minus ±X, ±X minus ±O
tXI.)
±O
+0
F2XM1
Multiplication
+0
+0
+0· +0, -0·-0
+0
-0
-0
+0· -0, -0· +0
-0
FRNDINT
+O·+X,+X·+O +0 +0
+0
+Oo-X,-X.+O -0 -0
-0
-0· +X, +X· -0
-0
FXTRACT
-0· -X, -X·-O
+0 +0
Both +0
+X·+Y,-x·-y
+ 0,
-0
Both -0
+Xe-Y,-X·+Y
-0, underflow(7)
NOTES:
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.
1-26
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Intel 80286 Specifications

General

Processor Type	Microprocessor
Clock Speed	6 MHz to 25 MHz
Transistor Count	134, 000
Addressable Memory	16 MB
Instruction Set	x86
Architecture	x86
Data Bus Width	16-bit
Address Bus Width	24-bit
Operating Modes	Real mode, Protected mode
Process Technology	1.5 µm
Voltage	5V
Introduced	1982
Package	68-pin PGA