AB45.3.1
AB45.3.1 J. K. Reid: Functions for Manipulating Floating-point Numbers, pages 6-15
Page 5-6
Page 7-8
Page 9-10
Page 11-12
Page 13-14
Page 15-16
Postscript
The functions epsilon, exponent, and set_exponent of Fortran 90
(and Fortran 95 and Fortran 2003) now provide the functionality that
was requested.