On 5/21/20 2:43 AM, LIU Zhiwei wrote:
> @@ -174,6 +175,9 @@ static int write_frm(CPURISCVState *env, int csrno,
> target_ulong val)
> env->mstatus |= MSTATUS_FS;
> #endif
> env->frm = val & (FSR_RD >> FSR_RD_SHIFT);
> + if (!riscv_cpu_set_rounding_mode(env, env->frm)) {
> + return -1;
> + }
This will raise an exception immediately in helper_csrrw().
According to Section 8.2, the no exception should occur until the next fp
operation that uses the invalid frm.
You're doing this just fine in helper_set_rounding_mode(), which is sufficient
for scalar fp ops. Without looking forward to later patches, I suppose we'll
need to do something else for vector fp ops.
r~
