The ARM architecture provides some shift and rotation operations:

mnemonic	operation	action
`LSL #n`	Logical Shift Left by `n` bits.	Signed or unsigned multiplication by $2^{n}$ .
`LSR #n`	Logical Shift Right by `n` bits.	Unsigned division by $2^{n}$ .
`ASR #n`	Arithmetic Shift Right by `n` bits.	Signed division by $2^{n}$ .
`ROR #n`	Rotate Right by `n` bits.	Rotate bits around, and set Carry to LSB.
`RRX #n`	Rotate Right Extended by `n` bits.	Rotate bits around through Carry.

Using Shift and Rotation Operations

One of the inputs of any instruction can be shifted or rotated. For example:

MOV R0, R0, LSL #1 ; R0 <= R0 * 2

This can be used to make some operations more efficient. For example, consider the following two approaches to multiplication by 5:

MOV R1, #5 ; literals cannot be used with MUL
MUL R0, R1

ADD R0, R0, LSL #2

CS Notes