The weapons efficiency and yeilds would be significatly higher than hiroshima.. the weapon would also be nominally 'cleaner'.
Pakistan would be able to 'hurt' india; but i suspect the weight of population, military dispersal and number of warheads gives india the 'three hundred pound gorillia' title in a slugfest between the two.
the biggest unknown is china... and i suspect that after pakistan and india get through with each other, china will regretfully step in and take the survivors toys away, and annex whatever territory remaining that ain't glowing at night.