hpmcounter4

User-mode Hardware Performance Counter 1

Alias for M-mode CSR mhpmcounter4.

Privilege mode access is controlled with mcounteren.HPM4 <%- if ext?(:S) -%> , scounteren.HPM4 <%- if ext?(:H) -%> , and hcounteren.HPM4 <%- end -%> <%- end -%> as follows:

<%- if ext?(:H) -%>

mcounteren.HPM4

scounteren.HPM4

hcounteren.HPM4

hpmcounter4 behavior

S-mode

U-mode

VS-mode

VU-mode

0

-

-

IllegalInstruction

IllegalInstruction

IllegalInstruction

IllegalInstruction

1

0

0

read-only

IllegalInstruction

VirtualInstruction

VirtualInstruction

1

1

0

read-only

read-only

VirtualInstruction

VirtualInstruction

1

0

1

read-only

IllegalInstruction

read-only

VirtualInstruction

1

1

1

read-only

read-only

read-only

read-only

<%- elsif ext?(:S) -%>

mcounteren.HPM4

scounteren.HPM4

hpmcounter4 behavior

S-mode

U-mode

0

-

IllegalInstruction

IllegalInstruction

1

0

read-only

IllegalInstruction

1

1

read-only

read-only

<%- else -%>

mcounteren.HPM4

hpmcounter4 behavior

U-mode

0

IllegalInstruction

1

read-only

<%- end -%>

Attributes

Defining Extension

  • Zihpm, version >= Zihpm@2.0.0

CSR Address

0xc04

Length

64-bit

Privilege Mode

U

Format

hpmcounter4 format
Figure 1. hpmcounter4 format

Field Summary

Name Location Type Reset Value

hpmcounter4.COUNT

63:0

RO-H

UNDEFINED_LEGAL

Fields

COUNT

Location

63:0

Description

Alias of mhpmcounter4.COUNT.

Type

RO-H

Reset value

UNDEFINED_LEGAL

Software read

This CSR may return a value that is different from what is stored in hardware.

if (mode() == PrivilegeMode::S) {
  if (CSR[mcounteren].HPM4 == 1'b0) {
    raise(ExceptionCode::IllegalInstruction, mode(), $encoding);
  }
} else if (mode() == PrivilegeMode::U) {
  if (CSR[misa].S == 1'b1) {
    if ((CSR[mcounteren].HPM4 & CSR[scounteren].HPM4) == 1'b0) {
      raise(ExceptionCode::IllegalInstruction, mode(), $encoding);
    }
  } else if (CSR[mcounteren].HPM4 == 1'b0) {
    raise(ExceptionCode::IllegalInstruction, mode(), $encoding);
  }
} else if (mode() == PrivilegeMode::VS) {
  if (CSR[hcounteren].HPM4 == 1'b0 && CSR[mcounteren].HPM4 == 1'b1) {
    raise(ExceptionCode::VirtualInstruction, mode(), $encoding);
  } else if (CSR[mcounteren].HPM4 == 1'b0) {
    raise(ExceptionCode::IllegalInstruction, mode(), $encoding);
  }
} else if (mode() == PrivilegeMode::VU) {
  if (CSR[hcounteren].HPM4 & CSR[scounteren].HPM4) == 1'b0) && (CSR[mcounteren].HPM4 == 1'b1 {
    raise(ExceptionCode::VirtualInstruction, mode(), $encoding);
  } else if (CSR[mcounteren].HPM4 == 1'b0) {
    raise(ExceptionCode::IllegalInstruction, mode(), $encoding);
  }
}
return read_hpm_counter(4);