hpmcounter24

User-mode Hardware Performance Counter 21

Alias for M-mode CSR mhpmcounter24.

Privilege mode access is controlled with mcounteren.HPM24 as follows:

mcounteren.HPM24

hpmcounter24 behavior

U-mode

0

IllegalInstruction

1

read-only

Attributes

Defining Extension

  • Zihpm, version >= 0

CSR Address

0xc18

Length

64-bit

Privilege Mode

U

Format

hpmcounter24 format
Figure 1. hpmcounter24 format

Field Summary

Name Location Type Reset Value

COUNT

63:0

RO-H

UNDEFINED_LEGAL

Fields

COUNT

Location

63:0

Description

Alias of mhpmcounter24.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].HPM24 == 1'b0) {
    raise(ExceptionCode::IllegalInstruction, mode(), $encoding);
  }
} else if (mode() == PrivilegeMode::U) {
  if (CSR[misa].S == 1'b1) {
    if ((CSR[mcounteren].HPM24 & CSR[scounteren].HPM24) == 1'b0) {
      raise(ExceptionCode::IllegalInstruction, mode(), $encoding);
    }
  } else if (CSR[mcounteren].HPM24 == 1'b0) {
    raise(ExceptionCode::IllegalInstruction, mode(), $encoding);
  }
} else if (mode() == PrivilegeMode::VS) {
  if (CSR[hcounteren].HPM24 == 1'b0 && CSR[mcounteren] == 1'b1) {
    raise(ExceptionCode::VirtualInstruction, mode(), $encoding);
  } else if (CSR[mcounteren].HPM24 == 1'b0) {
    raise(ExceptionCode::IllegalInstruction, mode(), $encoding);
  }
} else if (mode() == PrivilegeMode::VU) {
  if (CSR[hcounteren].HPM24 & CSR[scounteren].HPM24) == 1'b0) && (CSR[mcounteren].HPM24 == 1'b1 {
    raise(ExceptionCode::VirtualInstruction, mode(), $encoding);
  } else if (CSR[mcounteren].HPM24 == 1'b0) {
    raise(ExceptionCode::IllegalInstruction, mode(), $encoding);
  }
}
return read_hpm_counter(24);