hpmcounter4
User-mode Hardware Performance Counter 1
Alias for M-mode CSR mhpmcounter4.
Privilege mode access is controlled with mcounteren.HPM4 as follows:
hpmcounter4 behavior |
|
---|---|
U-mode |
|
0 |
|
1 |
read-only |
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] == 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);