The result of a right shift of a negative-value signed integral type (§3.3.7)
Shifting a negative value to the right yields half the absolute value, rounded down. For example, –253 (binary 11111111 00000011) shifted right one bit produces –127 (binary 11111111 10000001). A positive 253 shifts right to produce +126.
Right shifts preserve the sign bit. When a signed integer shifts right, the most-significant bit remains set. When an unsigned integer shifts right, the most-significant bit is cleared. Thus, if 0xF000 is signed, a right shift produces 0xF800. If 0xF000 is unsigned, the result is 0x7800.
Shifting a positive number right sixteen times produces 0x0000. Shifting a negative number right sixteen times produces 0xFFFF.