Physical size of the registers for x86
Not really greatly researched, a quick search on x86 registers led me here, but yes:

The L in CL is for Lower, its the lower byte of the 16-bit counter register CX, which itself is the lower half of the 32-bit ECX register.

This logic applies to most registers in IA32 (not all).


  Are all the registers physically have the same size (say 32 bits)


no.