Binary floating-point constant

A binary floating-point constant is a mantissa followed by an exponent and the letter B.

The mantissa is a binary fixed-point constant. The exponent is the letter E, S, D, or Q followed by an optionally-signed decimal integer (meaning 2 to the power of this integer). Constants using E have a precision (p) where p is the number of binary digits of the mantissa. Constants using S, D, and Q always have maximum single, double, and extended precisions, respectively.