On 2020/7/1 5:51, Richard Henderson wrote:
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.
Agree. I think the 'bug ' is false positive. Although the round mode process code is confusing, it it right. Zhiwei
r~
