On 6/30/20 1:12 PM, Alistair Francis wrote:
> When a guest specificies the the rounding mode should be dynamic 0b111
> then we want to re-caclulate the rounding mode on each instruction. The
> gen_helper_set_rounding_mode() function will correctly check the
> rounding mode and handle a dynamic rounding, we just need to make sure
> it's always called if dynamic rounding is selected.
>
> Fixes: 1885350 ("RISCV dynamic rounding mode is not behaving correctly")
> Signed-off-by: Alistair Francis <alistair.fran...@wdc.com>
> ---
> target/riscv/translate.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/target/riscv/translate.c b/target/riscv/translate.c
> index ce71ca7a92..a39eba679a 100644
> --- a/target/riscv/translate.c
> +++ b/target/riscv/translate.c
> @@ -490,7 +490,7 @@ static void gen_set_rm(DisasContext *ctx, int rm)
> {
> TCGv_i32 t0;
>
> - if (ctx->frm == rm) {
> + if (ctx->frm == rm && rm != 7) {
> return;
This should not be necessary.
It was my understanding that after the set to the csr, that we would end the
TB. That's certainly what I see in RISCV_OP_CSR_POST.
The next TB will begin wiht ctx->frm = -1, so we will reset the rounding mode
with 7. It would be good to understand what's really going on here.
r~
