On Oct 25, 2020, at 4:37 PM, Roger Espasa <roger.espasa@...> wrote:

Did you keep/add text encouraging implementations to indeed raise illegal on reserved encodings ? I went through the patch (rather quickly) and did not see it. 

Roger 

On Mon, 26 Oct 2020 at 00:32, Krste Asanovic <krste@...> wrote:

I'm working through updates to vector spec, and one part of clean up
is changing text where it has mandatory raising of illegal instruction
exceptions on unsupported encodings to instead state the encoding is
"reserved".  This will allow future extensions to use these encodings,
while current implementations can continue (and are encouraged) to
raise illegal instruction exceptions on unsupported reserved
encodings.

We didn't talk through this in meetings, but I assume this will be
uncontroversial.

https://github.com/riscv/riscv-v-spec/commit/96a9bc96640b9a12bf8868634671e501f2a24b77

Krste