largest normalized number.

Question

what is the largest normalized number hat can be represented in iee754. 

they say the exponent can't be all ones so if can't be all ones then how the exponent - bias came to be 127. the maximum exponent should be 254 and it should be 126. and why we use -126 while finding denormalized number. 

Answer 1

Denormalized numbers are for filling the gap between 0 and the smallest positive number in normalized representation. This link should be good.

http://steve.hollasch.net/cgindex/coding/ieeefloat.html