Arithmetic Operations on Extreme Values

This section describes the results of basic arithmetic operations with extreme and ordinary values. We assume all inputs are positive, and no traps, overflow, underflow, or other exceptions happen.

Table C-3 Extreme Value Abbreviations

Abbreviation	Meaning
Sub	Subnormal number
Num	Normalized number
Inf	Infinity (positive or negative)
NaN	Not a Number
Uno	Unordered

Table C-4 Extreme Values: Addition and Subtraction

Left Operand		Right Operand
		0	Sub	Num	Inf	NaN
0		0	Sub	Num	Inf	NaN
Sub		Sub	Sub	Num	Inf	NaN
Num		Num	Num	Num	Inf	NaN
Inf		Inf	Inf	Inf	Note	NaN
NaN		NaN	NaN	NaN	NaN	NaN

Note: Inf Inf and Inf + Inf = Inf ; Inf - Inf = NaN.

Table C-5 Extreme Values: Multiplication

Left Operand		Right Operand
		0	Sub	Num	Inf	NaN
0		0	0	0	NaN	NaN
Sub		0	0	NS	Inf	NaN
Num		0	NS	Num	Inf	NaN
Inf		NaN	Inf	Inf	Inf	NaN
NaN		NaN	NaN	NaN	NaN	NaN

In the above table, NS means either Num or Sub result possible.

Table C-6 Extreme Values: Division

Left Operand		Right Operand
		0	Sub	Num	Inf	NaN
0		NaN	0	0	0	NaN
Sub		Inf	Num	Num	0	NaN
Num		Inf	Num	Num	0	NaN
Inf		Inf	Inf	Inf	NaN	NaN
NaN		NaN	NaN	NaN	NaN	NaN

Table C-7 Extreme Values: Comparison

Left Operand		Right Operand
		0	Sub	Num	Inf	NaN
0		=	<	<	<	Uno
Sub		>		<	<	Uno
Num		>	>		<	Uno
Inf		>	>	>	=	Uno
NaN		Uno	Uno	Uno	Uno	Uno

Notes:

• If either X or Y is NaN, then X.NE.Y is .TRUE., and the others (.EQ., .GT., .GE., .LT., .LE.) are .FALSE.

• +0 compares equal to -0.

• If any argument is NaN, then the results of MAX or MIN are undefined.