# Implicit Leading 1 in Binary Floating Point

Is the convention of dropping the leading 1 when storing the significand a given in all binary floating point representations or not necessarily?

• It is so in all IEEE formats but maybe not enforced as a convention for all representations – Bug Killer Oct 30 '13 at 2:22
• Yea, I'm preparing for an exam, and the sample questions on floating point do not specify whether the leading 1 is implied or explicit. – Isaac Kleinman Oct 30 '13 at 3:51
• If you have a representation using an array of bits, for example, then the leading 1 is implicit. On the other hand if the representation is like the scientific notation, the 1 should be explicit as the numbers are represented in the form $1,bbb.. \cdot 2^{-p}$ where the $b$'s are the mantissa bits and $-p$ is the exponent. – Alejandro Sazo Oct 30 '13 at 4:16