time
Timer for RDTIME Instruction
| This CSR does not exist, and access will cause an IllegalInstruction exception. |
|
Shadow of the memory-mapped M-mode CSR Privilege mode access is controlled with mcounteren.TM, scounteren.TM, and hcounteren.TM as follows:
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Attributes
Defining Extension |
|
|---|---|
CSR Address |
0xc01 |
Length |
64-bit |
Privilege Mode |
U |
Software read
This CSR may return a value that is different from what is stored in hardware.
if (!TIME_CSR_IMPLEMENTED) {
%%LINK%func;unimplemented_csr;unimplemented_csr%%($encoding);
}
if (%%LINK%func;mode;mode%%() == PrivilegeMode::S) {
if (%%LINK%csr_field;mcounteren.TM;CSR[mcounteren].TM%% == 1'b0) {
%%LINK%func;raise;raise%%(ExceptionCode::IllegalInstruction, %%LINK%func;mode;mode%%(), $encoding);
}
} else if (%%LINK%func;mode;mode%%() == PrivilegeMode::U) {
if (%%LINK%csr_field;misa.S;CSR[misa].S%% == 1'b1) {
if ((%%LINK%csr_field;mcounteren.TM;CSR[mcounteren].TM%% & %%LINK%csr_field;scounteren.TM;CSR[scounteren].TM%%) == 1'b0) {
%%LINK%func;raise;raise%%(ExceptionCode::IllegalInstruction, %%LINK%func;mode;mode%%(), $encoding);
}
} else if (%%LINK%csr_field;mcounteren.TM;CSR[mcounteren].TM%% == 1'b0) {
%%LINK%func;raise;raise%%(ExceptionCode::IllegalInstruction, %%LINK%func;mode;mode%%(), $encoding);
}
} else if (%%LINK%func;mode;mode%%() == PrivilegeMode::VS) {
if (%%LINK%csr_field;hcounteren.TM;CSR[hcounteren].TM%% == 1'b0 && %%LINK%csr_field;mcounteren.TM;CSR[mcounteren].TM%% == 1'b1) {
%%LINK%func;raise;raise%%(ExceptionCode::VirtualInstruction, %%LINK%func;mode;mode%%(), $encoding);
} else if (%%LINK%csr_field;mcounteren.TM;CSR[mcounteren].TM%% == 1'b0) {
%%LINK%func;raise;raise%%(ExceptionCode::IllegalInstruction, %%LINK%func;mode;mode%%(), $encoding);
}
} else if (%%LINK%func;mode;mode%%() == PrivilegeMode::VU) {
if (%%LINK%csr_field;hcounteren.TM;CSR[hcounteren].TM%% & %%LINK%csr_field;scounteren.TM;CSR[scounteren].TM%%) == 1'b0) && (%%LINK%csr_field;mcounteren.IR;CSR[mcounteren].IR%% == 1'b1 {
%%LINK%func;raise;raise%%(ExceptionCode::VirtualInstruction, %%LINK%func;mode;mode%%(), $encoding);
} else if (%%LINK%csr_field;mcounteren.TM;CSR[mcounteren].TM%% == 1'b0) {
%%LINK%func;raise;raise%%(ExceptionCode::IllegalInstruction, %%LINK%func;mode;mode%%(), $encoding);
}
}
return %%LINK%func;read_mtime;read_mtime%%();