Zcmt Extension
Synopsis
Zcmt adds the table jump instructions and also adds the jvt CSR. The jvt CSR requires a state enable if Smstateen is implemented. See [csrs-jvt] for details.
This extension reuses some encodings from c.fsdsp. Therefore it is incompatible with [Zcd], which is included when C and D extensions are both present.
| Zcmt is primarily targeted at embedded class CPUs due to implementation complexity. Additionally, it is not compatible with RVA profiles. |
The Zcmt extension depends on the [Zca] and Zicsr extensions.
| RV32 | RV64 | Mnemonic | Instruction |
|---|---|---|---|
yes |
yes |
cm.jt index |
|
yes |
yes |
cm.jalt index |
Parameters
This extension has the following implementation options (AKA parameters):
- HSTATEEN_JVT_TYPE
-
Type
string
Valid Values
[rw, read-only-0, read-only-1]
Description
Behavior of the hstateen0.JVT bit:
-
'rw': read-write
-
'read-only-0': read-only, fixed to 0
-
'read-only-1': read-only, fixed to 1
-
- MSTATEEN_JVT_TYPE
-
Type
string
Valid Values
[rw, read-only-0, read-only-1]
Description
Behavior of the mstateen0.JVT bit:
-
'rw': read-write
-
'read-only-0': read-only, fixed to 0
-
'read-only-1': read-only, fixed to 1
-
- SSTATEEN_JVT_TYPE
-
Type
string
Valid Values
[rw, read-only-0, read-only-1]
Description
Behavior of the sstateen0.JVT bit:
-
'rw': read-write
-
'read-only-0': read-only, fixed to 0
-
'read-only-1': read-only, fixed to 1
-