0100nnnn00100101
t ← ZeroExtend1(T);
op1 ← ZeroExtend32(Rn);
oldt ← t;
t ← op1< 0 FOR 1 >;
op1 ← (op1 >> 1) ∨ (oldt << 31);
Rn ← Register(op1);
T ← Bit(t);