sstatus

Supervisor Status

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

All fields in sstatus are aliases of the same field in mstatus.

Attributes

CSR Address	0x100
Defining extension	S, version >= 0
Length	64-bit
Privilege Mode	S

CSR Address

0x100

Defining extension

S, version >= 0

Length

64-bit

Privilege Mode

Format

Figure 1. sstatus format

Field Summary

Name Location Type Reset Value

Name	Location	Type	Reset Value
`SD`	63	RO-H	UNDEFINED_LEGAL
`UXL`	33:32	RO	UNDEFINED_LEGAL
`MXR`	19	RW	UNDEFINED_LEGAL
`SUM`	18	RW	UNDEFINED_LEGAL
`XS`	16:15	RO	UNDEFINED_LEGAL
`FS`	14:13	RW-H	UNDEFINED_LEGAL
`VS`	10:9	RW-H	UNDEFINED_LEGAL
`SPP`	8	RW-H	UNDEFINED_LEGAL
`UBE`	6	RO	UNDEFINED_LEGAL
`SPIE`	5	RW-H	UNDEFINED_LEGAL
`SIE`	1	RW-H	UNDEFINED_LEGAL

SD

RO-H

UNDEFINED_LEGAL

UXL

33:32

UNDEFINED_LEGAL

MXR

UNDEFINED_LEGAL

SUM

UNDEFINED_LEGAL

XS

16:15

UNDEFINED_LEGAL

FS

14:13

RW-H

UNDEFINED_LEGAL

VS

10:9

RW-H

UNDEFINED_LEGAL

SPP

RW-H

UNDEFINED_LEGAL

UBE

UNDEFINED_LEGAL

SPIE

RW-H

UNDEFINED_LEGAL

SIE

RW-H

UNDEFINED_LEGAL

Fields

`SD`

Location: sstatus[63]
Description: State Dirty

Alias of mstatus.SD.
Type

RO-H	Read-Only with Hardware update Writes are ignored. Reads reflect a value dynamically generated by hardware.

Reset value: UNDEFINED_LEGAL

`UXL`

Location: sstatus[33:32]
Description: U-mode XLEN

Alias of mstatus.UXL.
Type

RO	Read-Only Field has a hardwired value that does not change. Writes to an RO field are ignored.

Reset value: UNDEFINED_LEGAL

`MXR`

Location: sstatus[19]
Description: Make eXecutable Readable

Alias of mstatus.MXR.
Type

RW	Read-Write Field is writable by software. Any value that fits in the field is acceptable and shall be retained for subsequent reads.

Reset value: UNDEFINED_LEGAL

`SUM`

Location: sstatus[18]
Description: permit Supervisor Memory Access

Alias of mstatus.SUM.
Type

RW	Read-Write Field is writable by software. Any value that fits in the field is acceptable and shall be retained for subsequent reads.

Reset value: UNDEFINED_LEGAL

`XS`

Location: sstatus[16:15]
Description: Custom (X) extension context Status.

Alias of mstatus.XS.
Type

RO	Read-Only Field has a hardwired value that does not change. Writes to an RO field are ignored.

Reset value: UNDEFINED_LEGAL

`FS`

Location: sstatus[14:13]
Description: Floating point context status.

Alias of mstatus.FS.
Type

RW-H	Read-Write with Hardware update Field is writable by software. Any value that fits in the field is acceptable. Hardware also updates the field without an explicit software write.

Reset value: UNDEFINED_LEGAL

`VS`

Location: sstatus[10:9]
Description: Vector context status.

Alias of mstatus.VS.
Type

RW-H	Read-Write with Hardware update Field is writable by software. Any value that fits in the field is acceptable. Hardware also updates the field without an explicit software write.

Reset value: UNDEFINED_LEGAL

`SPP`

Location: sstatus[8]
Description: S-mode Previous Privilege

Alias of mstatus.SPP.
Type

RW-H	Read-Write with Hardware update Field is writable by software. Any value that fits in the field is acceptable. Hardware also updates the field without an explicit software write.

Reset value: UNDEFINED_LEGAL

`UBE`

Location: sstatus[6]
Description: U-mode Big Endian

Alias of mstatus.UBE.
Type

RO	Read-Only Field has a hardwired value that does not change. Writes to an RO field are ignored.

Reset value: UNDEFINED_LEGAL

`SPIE`

Location: sstatus[5]
Description: S-mode Previous Interrupt Enable

Alias of mstatus.SPIE.
Type

RW-H	Read-Write with Hardware update Field is writable by software. Any value that fits in the field is acceptable. Hardware also updates the field without an explicit software write.

Reset value: UNDEFINED_LEGAL

`SIE`

Location: sstatus[1]
Description: S-mode Interrupt Enable

Alias of mstatus.SIE.
Type

RW-H	Read-Write with Hardware update Field is writable by software. Any value that fits in the field is acceptable. Hardware also updates the field without an explicit software write.

Reset value: UNDEFINED_LEGAL