public void executeSB(ITypeInstruction instruction) { 
		RegisterFile regFile = RegisterFile.getInstance();
		Memory memory = Memory.getInstance();
		
		int value = regFile.getRegisterValue(instruction.getRegSource()) & 0xff ;
		memory.setMemoryValue( regFile.getRegisterValue(instruction.getRegTarget())
				+instruction.getImmediateVal(), value);
		AppContext.PROGRAM_COUNTER++;	
/*
	Description:
	The least significant byte of $t is stored at the specified address.
	Operation:
	MEM[$s + offset] = (0xff & $t); advance_pc (4);
	Syntax:
	sb $t, offset($s)
	Encoding:
	1010 00ss ssst tttt iiii iiii iiii iiii
		 */ 
	}