arch-riscv: Add basic features toward rv32 support
Various changes to support rv32:
1. Add riscv_bits field into RiscvISA to switch rv_type
2. Add rv_type field into ExtMachInst
3. Split various constants into rv32/rv64 version
4. Fix mcause/mstatus/misa setting per rv_type
5. Split RiscvCPU into rv32/rv64
6. Fix how reset/branch create new pc so rv_type is preserved
7. Tag gdb-xml only for rv64
TODO:
Add rv32 gdb-xml
Add rv32 implementation into decoder
Currently there're three places where we store the rv_type information
(1) ISA (2) PCState (3) ExtMachInst. In theory, the ISA should be the
source of truth, and propagates information into PCState, then Inst.
However, there is an API on RiscvProcess that let users modify the
rv_type in PCState, so there's a chance to get inconsistent rv_type. We
should either modify the structure so such kind of usage is well
supported, or just prohibit people from setting a different rv_type.
Change-Id: If5685ae60f8d18f4f2e18137e235989e63156404
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/63091
Reviewed-by: Yu-hsin Wang <yuhsingw@google.com>
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
21 files changed
