Floating-Point IP Cores User Guide

ID 683750
Date 10/27/2021

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1.6.3. Rounding

The IEEE-754 standard defines four types of rounding modes, which are:
  • round-to-nearest-even
  • round-toward-zero
  • round-toward-positive-infinity
  • round-toward-negative-infinity

Intel floating-point IP cores support only the most commonly used rounding mode, which is the round-to-nearest-even mode (TO_NEAREST). With round-to-nearest-even, the IP core rounds the result to the nearest floating-point number. If the result is exactly halfway between two floating-point numbers, the IP core rounds the result so that the LSB becomes a zero, which is even.