On 8/28/19 11:54 AM, Richard Henderson wrote: > But it might be reasonable to include (VSTART == 0 && VL == VLMAX) as a > single bit.
BTW, it is reasonable to check VSTART == 0 always. Quoting the spec: # Implementations are permitted to raise illegal instruction exceptions # when attempting to execute a vector instruction with a value of vstart # that the implementation can never produce when executing that same # instruction with the same vtype setting. Since qemu will never interrupt a single instruction, each vector instruction will always run to completion, which clears VSTART. Since QEMU will never produce a non-zero value of VSTART, it is allowed to trap on any non-zero setting of VSTART. I.e. it can be handled at translation time alongside VILL. r~
