Raise exception when RV32E instructions use x16-x31#578

jserv merged 1 commit intosysprog21:mastersysprog21/rv32emu:masterfrom

eleanorLYJ:avoid-using-over-16-regs-RV32EeleanorLYJ/rv32emu:avoid-using-over-16-regs-RV32ECopy head branch name to clipboard