Instruction get0(int index) {
			Instruction instr = borderInstr;
			if (index < instructionCount / 2) {
				for (int i = 0; i <= index; i++)
					instr = instr.nextByAddr;
			} else {
				for (int i = instructionCount; i > index; i--)
					instr = instr.prevByAddr;
			}
			return instr;
		}