The result of converting an integer to a shorter signed integer, or the result of converting an unsigned integer to a signed integer of equal length, if the value cannot be represented (§3.2.1.2)
When a long integer is cast to a short, or a short is cast to a char, the least-significant bytes are retained.
For example, this line
short x = (short)0x12345678L;
assigns the value 0x5678 to x, and this line
char y = (char)0x1234;
assigns the value 0x34 to y.
When signed variables are converted to unsigned and vice versa, the bit patterns remain the same. For example, casting –2 (0xFE) to an unsigned value yields 254 (also 0xFE).