POS_OP
#define CREATE_ABC(o,a,b,c) ((cast(Instruction, o)<<POS_OP) \
#define CREATE_ABx(o,a,bc) ((cast(Instruction, o)<<POS_OP) \
#define CREATE_Ax(o,a) ((cast(Instruction, o)<<POS_OP) \
#define POS_A (POS_OP + SIZE_OP)
#define GET_OPCODE(i) (cast(OpCode, ((i)>>POS_OP) & MASK1(SIZE_OP,0)))
#define SET_OPCODE(i,o) ((i) = (((i)&MASK0(SIZE_OP,POS_OP)) | \
((cast(Instruction, o)<<POS_OP)&MASK1(SIZE_OP,POS_OP))))