INSTRUCTION-DECODER
01	Code 00  instruction NOP	No operation
02	Code 01  instrutcion LDIM	Load immediate xx : r0 = xx
03	Code 02  instruction LD		Load direct : r0 = mem[xx]
05	Code 03  instruction ST		Store xx : mem[xx] = r1
0b	Code 04  instruction COPY	Copy R0 -> R1
0c	Code 05  instruction SHL	Shift left R1 -> R1
0d	Code 06  instruction SHR	Shift right R1 -> R1
0e	Code 07  instruction ADD	Add R0 + R1 -> R1
0f	Code 08  instruction SUB	Subtract R0 - R1 -> R1 
10	Code 09  instruction AND	And R0 & R1 -> R1
11	Code 0a  instruction OR		OR R0 | R1 -> R1
12	Code 0b  instruction NOT	Not ~R0 -> R1
13	Code 0c  instruction JAL	Jump always
15	Code 0d  instruction JN		Jump negative
17	Code 0e  instruction JZ		Jump zero
19	Code 0f  instruction JC		Jump carry
1b	Code 10  instruction JV		Jump overflow
1d	Code 11  instruction JSRWS	Jump subroutine without using stack, return with jin
25	Code 12  instruction JIN	Jump indirectly xx : jump to mem[xx]
28	Code 13  instruction JSR	Jump subroutine using stack, return with ret
2f	Code 14  instruction RET        Return from jsr subroutines
31	Code 15  instruction PUSH       Push R1
35	Code 16  instruction POP        Pop to R0
01	Code 17  instruction NOP
01	Code 18  instruction NOP
01	Code 19  instruction NOP
01	Code 1a  instruction NOP
01	Code 1b  instruction NOP
01	Code 1c  instruction NOP
01	Code 1d  instruction NOP
01	Code 1e  instruction NOP
01	Code 1f  instruction NOP
