Specifying Instruction Syntax and Semantics
type rt register field 20 5,
immdt signed field 15 16,
lw rt address emit opcode=35 rs=<address.base>
rt immdt=<address.offset>
attributes(i_type:load_type,dest_r:rt,lop_r:rs)
case s_ID : simm=immdt.[15:1] |< 16 || immdt;
case s_EX : lmar=lop+simm;
case s_MEM: dest=dcache[lmar];