mhpmcounter21

Machine Hardware Performance Counter 21

Programmable hardware performance counter.

Attributes

Defining Extension

  • Smhpm, version >= 0

CSR Address

0xb15

Length

64-bit

Privilege Mode

M

Format

mhpmcounter21 format
Figure 1. mhpmcounter21 format

Field Summary

Name Location Type Reset Value

COUNT

63:0
RW-H
RO
UNDEFINED_LEGAL
0

Fields

COUNT

Location

63:0

Description

[when="HPM_COUNTER_EN[21] == true"] + — + Performance counter for event selected in mhpmevent21.EVENT.

Increments every time event occurs unless:

  • mcountinhibit.HPM21 is set + — +
    [when="HPM_COUNTER_EN[21] == false"]
    Unimplemented performance counter. Must be read-only 0 (access does not cause trap).

Type
RW-H
RO
Reset value
UNDEFINED_LEGAL
0

Software read

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

if (HPM_COUNTER_EN[21]) {
  return read_hpm_counter(21);
} else {
  return 0;
}