please sir suggest me how will i install os android in the arm cortex m3
There have been hobby level ports of Linux to the Cortex M3 but no Linaro support. I'd recommend any number of other RTOSs for the M3 before attempting such a heavy kernel. As Peter stated, current versions of Android will run on Cortex-A (ARMv7) and some older versions of Android will run on ARM11 and ARM9 (ARMv6 and ARMv5) cores.