Nios II Classic Processor Reference Guide

ID 683620
Date 10/28/2016
Public
Document Table of Contents

3.9.5. Shift and Rotate Instructions

The following instructions provide shift and rotate operations. The number of bits to rotate or shift can be specified in a register or an immediate value.
Table 51.  Shift and Rotate Instructions
Instruction Description
rol
ror
roli
The rol and roli instructions provide left bit-rotation. roli uses an immediate value to specify the number of bits to rotate. The ror instructions provides right bit-rotation.

There is no immediate version of ror, because roli can be used to implement the equivalent operation.

sll
slli
sra
srl
srai
srli
These shift instructions implement the << and >> operators of the C programming language. The sll, slli, srl, srli instructions provide left and right logical bit-shifting operations, inserting zeros. The sra and srai instructions provide arithmetic right bit-shifting, duplicating the sign bit in the most significant bit. slli, srli and srai use an immediate value to specify the number of bits to shift.