HP-UX Floating-Point Guide

Chapter 2 37
Floating-Point Principles and the IEEE Standard for Binary Floating-Point Arithmetic
Floating-Point Formats
Figure 2-1 IEEE Single-Precision Format
The double-precision format is 64 bits long: 1 bit for the sign, 11 bits for
the exponent, and 52 bits for the fraction.
The double-precision format is sometimes divided conceptually into two
32-bit words. The word containing the sign bit, the exponent field, and
the first portion of the fraction field is referred to as the most
significant word. The other word, containing the last portion of the
fraction, is called the least significant word.
Figure 2-2 IEEE Double-Precision Format
The quad-precision format is 128 bits long: 1 bit for the sign, 15 bits for
the exponent, and 112 bits for the fraction. This format is divided
conceptually into four 32-bit words: the most significant word, two
middle words, and the least significant word.