fma: Correct Underflow logic
Created by: gregdavill
This change produces the correct behavior when executing MUL,FMADD type instruction. It flags underflow if result with unbounded exponent would lie between +/-b^(emin). Even if final rounded result is exactly [+/-]01.000000. We use the Use the sticky bits to validate this is the case for both MUL and FMADD.
Issue: #94 (closed)