I am learning assembly on a MC68HC12.

Can someone explain to me why the overflow flag, V=1, using the asr instruction on following binary number:

%1111 0100

the asr shift would be;

%1111 1010

V=1

another example

%0000 0001

the asr shift would be;

%0000 0000

why does V=1

I think I understand how overflow works with addition and subtraction but haven't been able to find a good explanation for its implementation with the shift instructions. Any recommended reading?

thanks