mstatush

Machine Status High

The mstatus register tracks and controls the hart’s current operating state.

Attributes

Defining Extension Sm, version >= 1.12

CSR Address

0x310

Length

32-bit

Privilege Mode

M

Format

mstatush format
Figure 1. mstatush format

Field Summary

Name Location Type Reset Value

mstatush.MDT

10

RW-H

UNDEFINED_LEGAL

mstatush.MPV

7

RW-H

UNDEFINED_LEGAL

mstatush.GVA

6

RW-H

0

mstatush.MBE

5

[when,"M_MODE_ENDIANNESS == "dynamic""] RW

[when,"M_MODE_ENDIANNESS != "dynamic""] RO

UNDEFINED_LEGAL

mstatush.SBE

4

[when,"S_MODE_ENDIANNESS == "dynamic""] RW

[when,"S_MODE_ENDIANNESS != "dynamic""] RO

UNDEFINED_LEGAL

Fields

MDT

Location

10

Description

Machine Disable Trap

Written to 1 when entering M-mode from an exception/interrupt. When returning via an MRET instruction, the bit is written to 0. On reset in set to 1, and software should write it to 0 when boot sequence is done. When mstatush.MDT=1, direct write by CSR instruction cannot set mstatus.MIE to 1.

Type

RW-H

Reset value

UNDEFINED_LEGAL

MPV

Location

7

Description

Machine Previous Virtualization mode

Written with the prior virtualization mode when entering M-mode from an exception/interrupt. When returning via an MRET instruction, the virtualization mode becomes the value of MPV unless MPP=3, in which case the virtualization mode is always 0. Can also be written by software.

Type

RW-H

Reset value

UNDEFINED_LEGAL

GVA

Location

6

Description

Guest Virtual Address

When a trap is taken and a guest virtual address is written into mtval, GVA is set. When a trap is taken and a guest virtual address is written into mtval, GVA is cleared.

Type

RW-H

Reset value

0

MBE

Location

5

Description

see mstatus.MBE

Type

RW

RO

Reset value

UNDEFINED_LEGAL

SBE

Location

4

Description

see mstatus.SBE

Type

RW

RO

Reset value

UNDEFINED_LEGAL