LSL (immediate)

Logical shift left (immediate)

This instruction shifts a register value left by an immediate number of bits, shifting in zeros, and writes the result to the destination register.

Encoding: With zeros to left and right

31	30	29	28	27	26	25	24	23	22	21	20	19	18	17	16	15	14	13	12	11	10	9	8	7	6	5	4	3	2	1	0
	1	0	1	0	0	1	1	0
sf	opc								N	immr						imms						Rn					Rd

32-bit (sf == 0 && N == 0 && imms != 011111)

LSL <Wd>, <Wn>, #<shift>

Equivalent to: UBFM <Wd>, <Wn>, #(-<shift> MOD 32), #(31-<shift>)

64-bit (sf == 1 && N == 1 && imms != 111111)

LSL <Xd>, <Xn>, #<shift>

Equivalent to: UBFM <Xd>, <Xn>, #(-<shift> MOD 64), #(63-<shift>)

Explanations

<Wd>: Is the 32-bit name of the general-purpose destination register, encoded in the "Rd" field.
<Wn>: Is the 32-bit name of the general-purpose source register, encoded in the "Rn" field.
<shift>: For the "32-bit" variant: is the shift amount, in the range 0 to 31.
<shift>: For the "64-bit" variant: is the shift amount, in the range 0 to 63.
<Xd>: Is the 64-bit name of the general-purpose destination register, encoded in the "Rd" field.
<Xn>: Is the 64-bit name of the general-purpose source register, encoded in the "Rn" field.

Operational Notes

If PSTATE.DIT is 1:

• The execution time of this instruction is independent of:
  • The values of the data supplied in any of its registers.
  • The values of the NZCV flags.
• The response of this instruction to asynchronous exceptions does not vary based on:
  • The values of the data supplied in any of its registers.
  • The values of the NZCV flags.