On Mon, 23 Jun 2025 at 16:42, Richard Henderson <richard.hender...@linaro.org> wrote: > > On 6/23/25 07:20, Peter Maydell wrote: > > Exceedingly nitpicky nit: the pseudocode seems to require > > that if the SVL is < 256 bits because the implementation > > doesn't support any larger SVL then this UNDEF should take > > precedence over the SVE/ZA-enabled check, but if the SVL > > is < 256 bits because software has set it that way then > > that UNDEF check happens after the SVE/ZA-enabled check. > > (The former happens in the decode-pseudocode, the latter > > in the operation-pseudocode.) > > Gotcha. Will fix. > > Not all insns seem to have this split. For instance, FEAT_F64MM > ZIP[12] w/ Q operands only has the second operation test.
That's because all of FEAT_F64MM's insns require 256 bit vector lengths, so an implementation with only 128 bit VL can't implement FEAT_F64MM at all, and we get the UNDEF from the IsFeatureImplemented(FEAT_F64MM) check. thanks -- PMM
