My 1-7 opcodes

switch (opcode & 0xF000) {

        // this opcode jumps to address NNN
        case 0x1000:
            PC = opcode & 0x0FFF;

            break;
        // this one calls a subroutine and stores the return in the stack
        case 0x2000:
            stack[++SP] = PC;

            PC = opcode & 0x0FFF;
            break;
        // If VX == NN then skip the next instruction, the opcode it 0x3XNN
        case 0x3000:

            if (V[(opcode & 0x0F00) >>> 8] == (opcode & 0x00FF)) {
                PC += 4;
            } else {
                PC += 2;
            }
            break;
        // If VX != NN then skip the next instruction, the opcode is 0x3XNN
        case 0x4000:

            if (V[(opcode & 0x0F00) >>> 0x0008] != (opcode & 0x00FF)) {
                PC += 4;
            } else {
                PC += 2;
            }
            break;
        // we are comparing VX and VY, if they match then skip, the opcode is 5XY0
        case 0x5000:

            if (V[(opcode & 0x0F00) >>> 0x0008] == V[(opcode & 0x00F0) >>> 0x0004]) {
                PC += 4;
            } else {
                PC += 2;
            }
            break;
        // Set register VX to NN, opcode is 6XNN
        case 0x6000:
            V[(opcode & 0x0F00) >>> 0x0008] = (opcode & 0x00FF);

            PC += 2;
            break;

        // add value NN to register VX, opcode is 7XNN
        case 0x7000:
            V[(opcode & 0x0F00) >>> 8] += (opcode & 0x00FF);
            if ((V[(opcode & 0x0F00) >>> 8] >= 256)) {
                V[(opcode & 0x0F00) >>> 8] -= 256;
            }

            PC += 2;
        }