Nios II Custom Instruction User Guide

ID 683242
Date 4/27/2020
Document Table of Contents
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5.3.1. Nearest Rounding

Nearest Rounding corresponds to the IEEE 754-2008 “Round-to-Nearest RoundTiesAway” rounding mode. Nearest Rounding rounds the result to the nearest single-precision number. When the result is halfway between two single-precision numbers, the rounding chooses the upper number (larger values for positive results, smaller value for negative results).

Nearest Rounding has a maximum error of one-half ULP. Errors are not evenly distributed, because nearest rounding chooses the upper number more often than the lower number when results are randomly distributed.