Re: [PATCH v8 07/18] target/riscv: setup everything for rv64 to support rv128 execution

[Alistair Francis]

On Fri, Jan 7, 2022 at 7:04 AM Frédéric Pétrot
<frederic.petrot@univ-grenoble-alpes.fr> wrote:
>
> This patch adds the support of the '-cpu rv128' option to
> qemu-system-riscv64 so that we can indicate that we want to run rv128
> executables.
> Still, there is no support for 128-bit insns at that stage so qemu fails
> miserably (as expected) if launched with this option.
>
> Signed-off-by: Frédéric Pétrot <frederic.petrot@univ-grenoble-alpes.fr>
> Co-authored-by: Fabien Portas <fabien.portas@grenoble-inp.org>
> Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
> ---
>  include/disas/dis-asm.h |  1 +
>  target/riscv/cpu.h      |  1 +
>  disas/riscv.c           |  5 +++++
>  target/riscv/cpu.c      | 20 ++++++++++++++++++++
>  target/riscv/gdbstub.c  |  5 +++++
>  5 files changed, 32 insertions(+)
>
> diff --git a/include/disas/dis-asm.h b/include/disas/dis-asm.h
> index 08e1beec85..102a1e7f50 100644
> --- a/include/disas/dis-asm.h
> +++ b/include/disas/dis-asm.h
> @@ -459,6 +459,7 @@ int print_insn_nios2(bfd_vma, disassemble_info*);
>  int print_insn_xtensa           (bfd_vma, disassemble_info*);
>  int print_insn_riscv32          (bfd_vma, disassemble_info*);
>  int print_insn_riscv64          (bfd_vma, disassemble_info*);
> +int print_insn_riscv128         (bfd_vma, disassemble_info*);
>  int print_insn_rx(bfd_vma, disassemble_info *);
>  int print_insn_hexagon(bfd_vma, disassemble_info *);
>
> diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
> index fa5d238530..efe481f5fb 100644
> --- a/target/riscv/cpu.h
> +++ b/target/riscv/cpu.h
> @@ -38,6 +38,7 @@
>  #define TYPE_RISCV_CPU_ANY              RISCV_CPU_TYPE_NAME("any")
>  #define TYPE_RISCV_CPU_BASE32           RISCV_CPU_TYPE_NAME("rv32")
>  #define TYPE_RISCV_CPU_BASE64           RISCV_CPU_TYPE_NAME("rv64")
> +#define TYPE_RISCV_CPU_BASE128          RISCV_CPU_TYPE_NAME("rv128")

As this series only adds partial support for 128-bit support, I think
we should probably change this to "x-rv128". That way we indicate to
users that it is experimental. That allows us more flexibility in the
future to have breaking changes and will hopefully avoid confusion
about the current state. What do you think? I can just make the change
when I apply the patches.

Alistair