Is there any register in 89c52 whose contents are restored/ maintained evenafter hardware reset
Assuming you mean reset under power, no registers or SFRs are maintained, but the RAM is (at least till the C startup code clears it). If you need to have a good hold on this, there are derivatives such as the Philips P89C51Rx2 and P89C66x that have a SFR bit for this specific purpose (set at power on, you reset it - then on a reset under power it does not get set)

Erik