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H.1 Basic Formats

Numbers in the single and double formats are composed of the following three fields:
1.
1-bit sign s
2.
Biased exponent bias
3.
Fraction $f= \bullet b_{1} b_{2} \cdots b_{p-1}$
The range of the unbiased exponent E shall include every integer between two values Emin and Emax, inclusive, and also two other reserved values Emin-1 to encode ±0 and denormalized numbers, and Emax+1 to encode $\pm \infty$ and NaNs. The foregoing parameters are given in Table H.1. Each nonzero numerical value has just one encoding. The fields are interpreted as follows:


 
Table H.1: Summary of Format Parameters
  Format
Parameter Single Single
Extended
Double Double
Extended
p 24 $\geq 32$ 53 $\geq 64$
Emax +127 $\geq +1023$ +1023 $\geq +16383$
Emin -126 $\leq -1022$ -1022 $\leq -16382$
Exponent bias +127 unspecified +1023 unspecified
Exponent width in bits 8 $\geq 11$ 11 $\geq 15$
Format width in bits 32 $\geq 43$ 64 $\geq 79$



 
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5/13/1999