I see it on riscv-v-spec commit: 0e8cdeb26bb98de2b1089d79a681af2c5a65e712
vmv.x.s belong to VWXUNARY0 and OPMVV
But OPMVV has only vs1 no rs1, see :
So i think `vmv.x.s rd, vs2 # x[rd] = vs2 (rs1=0)` should be fixed to `vmv.x.s rd, vs2 # x[rd] = vs2 (vs1=0)` or
encode vmv.x.s to VRXUNARY0 and OPMVX?
see also : https://github.com/riscv/riscv-v-spec/issues/625