// sample_com.ucode

fetch0: a_sel=7, b_sel=7, alu_sel=AND, r6_write, mar_sel=LOAD;

fetch1: r7_write, a_sel=6, alu_sel=ADDA, c_in, read, ir0_sel=LOAD,
        if wait then goto fetch1 endif;

fetch2: a_sel=7, b_sel=7, alu_sel=AND, r6_write, mar_sel=LOAD;

fetch3: r7_write, a_sel=6, alu_sel=ADDA, c_in, read, ir1_sel=LOAD,
	if wait then goto fetch3 endif;

        goto opcode[IR_OPCODE];

// 0) NO_OP
opcode[0]: goto fetch0;

// 1) ADD (ri <- rj + rk)
opcode[1]: ri_sel, rj_sel, rk_sel, alu_sel=ADD, goto fetch0; 

// 2) LOAD_IMMEDIATE (ri <- ir_const8)
opcode[2]: result_sel=IR_CONST8, ri_sel, goto fetch0;

// 3) BRANCH_IF_ZERO (bz r3, ir_const8)
opcode[3]: a_sel=3, b_sel=3, alu_sel=SUBA, r6_write, result_sel=IR_CONST8
           if c_out then goto fetch0 else goto branch endif;
		
// 4) BRANCH_IF_NOT_ZERO (bnz r3, ir_const8)
opcode[4]: a_sel=3, b_sel=3, alu_sel=SUBA, r6_write, result_sel=IR_CONST8,
           if c_out then goto branch else goto fetch0 endif;

// 5) JUMP (jump ir_const8)
opcode[5]: a_sel=0, b_sel=0, alu_sel=AND, r6_write, result_sel=IR_CONST8
           goto branch;

// 6) MOVE (ri <- rj)
opcode[6]: ri_sel, rj_sel, alu_sel=ADDA, goto fetch0;

// 7) STORE_BYTE (mem[rj] <= rk)
opcode[7]: rj_sel, alu_sel=ADDA, mar_sel=LOAD, goto opcode7.1; 

// 8) LOAD_BYTE (ri <- mem[rj])
opcode[8]: rj_sel, alu_sel=ADDA, mar_sel=LOAD, goto opcode8.1; 

// 9) HALT
opcode[9]: goto opcode[9];

// (extended area and functions)
branch: r7_write, a_sel=7, b_sel=6, alu_sel=ADD, goto fetch0;
opcode7.1: a_sel=5, b_sel=5, alu_sel=SUB, c_in, r5_write;
		rk_sel, a_sel=5, alu_sel=OR, mdr_sel=LOAD_ALU;
memwrite: write,
		if wait then goto memwrite else goto fetch0 endif;
opcode8.1: read, mdr_sel=LOAD_MEM, 
		if wait then goto opcode8.1 endif;
		result_sel=MDR, ri_sel, goto fetch0;