IBM Floating Point Architecture - Single-precision 32-bit

Single-precision 32-bit

A single-precision binary floating-point number is stored in a 32-bit word:

1 7 24 width in bits +-+-------+------------------------+ |S| Exp | Fraction | +-+-------+------------------------+ 31 30 24 23 0 bit index (0 on right) bias +64

Note that in this format the initial bit is not suppressed, and the radix point is set to the left of the mantissa in increments of 4 bits.

Since the base is 16, the exponent in this form is about twice as large as the equivalent in IEEE 754, in order to have similar exponent range in binary, 9 exponent bits would be required.