Nios® II Processor Reference Guide

ID 683836
Date 10/22/2020
Public
Document Table of Contents

8.5.42. div

Instruction divide
Operation

rC ←  rA ÷ rB

Assembler Syntax

div rC, rA, rB

Example

div r6, r7, r8

Description

Treating rA and rB as signed integers, this instruction divides rA by rB and then stores the integer portion of the resulting quotient to rC. After attempted division by zero, the value of rC is undefined. There is no divide-by-zero exception. After dividing –2147483648 by –1, the value of rC is undefined (the number +2147483648 is not representable in 32 bits). There is no overflow exception.

Nios® II processors that do not implement the div instruction cause an unimplemented instruction exception.

Usage

Remainder of Division:

If the result of the division is defined, then the remainder can be computed in rD using the following instruction sequence:

div rC, rA, rB

mul rD, rC, rB

sub rD, rA, rD

# The original div operation

# rD = remainder

Exceptions

Division error

Unimplemented instruction

Instruction Type

R

Instruction Fields

A = Register index of operand rA

B = Register index of operand rB

C = Register index of operand rC

Bit Fields
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
A B C 0x18
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
0x25 0 0x3a

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