Nios® II Processor Reference Guide

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

8.5.17. break

Instruction debugging breakpoint
Operation

bstatus ←  status

PIE ←  0

U ←  0

ba ←  PC + 4

PC ←  break handler address

Assembler Syntax

break

break imm5

Example

break

Description

Breaks program execution and transfers control to the debugger break-processing routine. Saves the address of the next instruction in register ba and saves the contents of the status register in bstatus. Disables interrupts, then transfers execution to the break handler.

The 5-bit immediate field imm5 is ignored by the processor, but it can be used by the debugger.

break with no argument is the same as break 0.

Usage

break is used by debuggers exclusively. Only debuggers should place break in a user program, operating system, or exception handler. The address of the break handler is specified with the Nios_II Processor parameter editor in Platform Designer.

Some debuggers support break and break 0 instructions in source code. These debuggers treat the break instruction as a normal breakpoint.

Exceptions

Break

Instruction Type

R

Instruction Fields

IMM5 = Type of breakpoint

Bit Fields
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
0 0 0x1e 0x34
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
0x34 IMM5 0x3a

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