Re: [PATCH v4 02/20] target/riscv: Sign extend pc for different XLEN

[Alistair Francis]

On Fri, Nov 12, 2021 at 1:56 AM LIU Zhiwei <zhiwei_liu@c-sky.com> wrote:
>
> When pc is written, it is sign-extended to fill the widest supported XLEN.
>
> Signed-off-by: LIU Zhiwei <zhiwei_liu@c-sky.com>
> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

Reviewed-by: Alistair Francis <alistair.francis@wdc.com>

Alistair

> ---
>  target/riscv/translate.c | 16 ++++++++++++----
>  1 file changed, 12 insertions(+), 4 deletions(-)
>
> diff --git a/target/riscv/translate.c b/target/riscv/translate.c
> index 1d57bc97b5..a6a73ced9e 100644
> --- a/target/riscv/translate.c
> +++ b/target/riscv/translate.c
> @@ -150,16 +150,24 @@ static void gen_check_nanbox_s(TCGv_i64 out, TCGv_i64 
> in)
>      tcg_gen_movcond_i64(TCG_COND_GEU, out, in, t_max, in, t_nan);
>  }
>
> +static void gen_set_pc(DisasContext *ctx, target_ulong dest)
> +{
> +    if (get_xl(ctx) == MXL_RV32) {
> +        dest = (int32_t)dest;
> +    }
> +    tcg_gen_movi_tl(cpu_pc, dest);
> +}
> +
>  static void generate_exception(DisasContext *ctx, int excp)
>  {
> -    tcg_gen_movi_tl(cpu_pc, ctx->base.pc_next);
> +    gen_set_pc(ctx, ctx->base.pc_next);
>      gen_helper_raise_exception(cpu_env, tcg_constant_i32(excp));
>      ctx->base.is_jmp = DISAS_NORETURN;
>  }
>
>  static void generate_exception_mtval(DisasContext *ctx, int excp)
>  {
> -    tcg_gen_movi_tl(cpu_pc, ctx->base.pc_next);
> +    gen_set_pc(ctx, ctx->base.pc_next);
>      tcg_gen_st_tl(cpu_pc, cpu_env, offsetof(CPURISCVState, badaddr));
>      gen_helper_raise_exception(cpu_env, tcg_constant_i32(excp));
>      ctx->base.is_jmp = DISAS_NORETURN;
> @@ -179,10 +187,10 @@ static void gen_goto_tb(DisasContext *ctx, int n, 
> target_ulong dest)
>  {
>      if (translator_use_goto_tb(&ctx->base, dest)) {
>          tcg_gen_goto_tb(n);
> -        tcg_gen_movi_tl(cpu_pc, dest);
> +        gen_set_pc(ctx, dest);
>          tcg_gen_exit_tb(ctx->base.tb, n);
>      } else {
> -        tcg_gen_movi_tl(cpu_pc, dest);
> +        gen_set_pc(ctx, dest);
>          tcg_gen_lookup_and_goto_ptr();
>      }
>  }
> --
> 2.25.1
>
>