

The following table gives the names of special cases and how each is represented.
Single and Double Precision:
Value Name  Sign  Exponent  Fraction  

MSB  Rest of Fraction  
NaN (nontrapping)  X  Max  1  X 
Trapping NaN  X  Max  0  Nonzero 
Positive Infinity  0  Max  Min  
Negative Infinity  1  Max  Min  
Positive Zero  0  Min  Min  
Negative Zero  1  Min  Min  
Denormalized Number  X  Min  Nonzero  
Normalized Number  X  NotMM  X 
Value Name  Sign  Exponent  Fraction  

MSB  
Rest of Fraction  
NaN (nontrapping)  X  Max  1  Nonzero 
Trapping NaN  X  Max  0  Nonzero 
Positive Infinity  0  Max  1  Min 
Negative Infinity  1  Max  1  Min 
Positive Zero  0  Min  Min  
Negative Zero  1  Min  Min  
Denormalized Number  X  Min  0  Nonzero 
Normalized Number  X  NotMM  1  X 
The algorithm for classification of a value into special cases
follows:
If (Exponent==Max)
If (Fraction==Min)
Then the number is Infinity (Positive or Negative
as determined by the Sign bit).
Else the number is NaN (Trapping if FractionMSB==0,
nonTrapping if FractionMSB==1).
Else If (Exponent==Min)
If (Fraction==Min)
Then the number is Zero (Positive or Negative
as determined by the Sign bit).
Else the number is Denormalized.
Else the number is Normalized.