Non linear DC voltage conditioning
Use a precision comparator with a really tiny bit of hysteresis to decide whether the input is above or below 1000.5 mV. Use the comparator output to select one of two signals using a transmission gate or multiplexer. 


Signal 1 is the input potted down by 10:1
Signal 2 is the input potted down by 100:1 


Use very good precision resistors and don't expect it to be seamless if there is noise on the DC signal or the "so-called" DC voltage is an AC signal.