Working With The Mpu; Mpu Region Read And Write Operations - Intel NIOS II Owner Reference Manual

•
After the
register sets, to ensure that all code can correctly address the small data sections.
•
Copy the
using the

3.5. Working with the MPU

This section provides a basic overview of MPU initialization and the MPU region read
and write operations.

3.5.1. MPU Region Read and Write Operations

MPU region read and write operations are operations that access MPU region attributes
through the
mpuacc.MASK
MPU region attributes.
MPU region read operations retrieve the current values for the attributes of a region.
Each MPU region read operation consists of the following actions:
•
Execute a
and
mpubase.D
•
Execute a
to one and the
and
mpuacc
•
Execute a
mpubase
•
Execute a
mpuacc
The MPU region read operation retrieves
mpuacc.LIMIT
Note:
Values for the
to the
mpuacc
MPU region write operations set new values for the attributes of a region. Each MPU
region write operation consists of the following actions:
•
Execute a
and
mpubase.D
•
Execute a
to one and the
The MPU region write operation sets the values for
mpuacc.LIMIT
region.
Normally, a
writing control registers take effect immediately after the
execution. However,
do not automatically flush the pipeline. Instead, system software is responsible for
Nios II Processor Reference Guide
68
register is initialized in the normal register set, copy it to all shadow
gp
register from the normal register set to all shadow register sets,
zero
instruction.
wrprs
and
mpubase mpuacc
, ,
mpuacc.LIMIT mpuacc.MT
instruction to the
wrctl
fields set to identify the MPU region.
instruction to the
wrctl
field cleared to zero. This action loads the
mpuacc.WR
register values.
instruction to the
rdctl
register value.
instruction to the
rdctl
register value.
, , and
mpuacc.MT
register are not actually retrieved until the
mpubase
register is performed.
instruction to the
wrctl
fields set to identify the MPU region.
instruction to the
wrctl
field cleared to zero.
mpuacc.RD
, , and
mpuacc.MT
instruction flushes the pipeline to guarantee that any side effects of
wrctl
instructions to the
wrctl
control registers. The
mpubase.BASE
, and
mpuacc.PERM
register with the
mpubase
register with the
mpuacc
register to read the loaded the
mpubase
register to read the loaded the
mpuacc
,
mpubase.BASE
values for the MPU region.
mpuacc.PERM
register with the
mpubase
register with the
mpuacc
mpubase.BASE
as the new attributes for the MPU
mpuacc.PERM
and
mpubase
3. Programming Model
NII-PRG | 2018.04.18
,
fields comprise the
mpubase.INDEX
field set
mpuacc.RD
mpubase
or
mpuacc.MASK
instruction
wrctl
mpubase.INDEX
field set
mpuacc.WR
,
mpuacc.MASK
instruction completes
wrctl
control registers
mpuacc
or