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LSLS (register)

Logical Shift Left, setting flags (register) shifts a register value left by a variable number of bits, shifting in zeros, writes the result to the destination register, and updates the condition flags based on the result. The variable number of bits is read from the bottom byte of a register.

This is an alias of MOV, MOVS (register-shifted register). This means:

It has encodings from the following instruction sets: A32 ( A1 ) and T32 ( T1 and T2 ) .

A1

313029282726252423222120191817161514131211109876543210
!= 111100011011(0)(0)(0)(0)RdRs0001Rm
condStype

Flag setting

LSLS{<c>}{<q>} {<Rd>,} <Rm>, <Rs>

is equivalent to

MOVS{<c>}{<q>} <Rd>, <Rm>, LSL <Rs>

and is always the preferred disassembly.

T1

1514131211109876543210
0100000010RsRdm
op

Logical shift left

LSLS{<q>} {<Rdm>,} <Rdm>, <Rs> // (Outside IT block)

is equivalent to

MOVS{<q>} <Rdm>, <Rdm>, LSL <Rs>

and is the preferred disassembly when !InITBlock().

T2

15141312111098765432101514131211109876543210
111110100001Rm1111Rd0000Rs
typeS

Flag setting

LSLS.W {<Rd>,} <Rm>, <Rs> // (Outside IT block, and <Rd>, <Rm>, <type>, <Rs> can be represented in T1)

LSLS{<c>}{<q>} {<Rd>,} <Rm>, <Rs>

is equivalent to

MOVS{<c>}{<q>} <Rd>, <Rm>, LSL <Rs>

and is always the preferred disassembly.

Assembler Symbols

<c>

See Standard assembler syntax fields.

<q>

See Standard assembler syntax fields.

<Rdm>

Is the first general-purpose source register and the destination register, encoded in the "Rdm" field.

<Rd>

Is the general-purpose destination register, encoded in the "Rd" field.

<Rm>

Is the first general-purpose source register, encoded in the "Rm" field.

<Rs>

Is the second general-purpose source register holding a shift amount in its bottom 8 bits, encoded in the "Rs" field.

Operation

The description of MOV, MOVS (register-shifted register) gives the operational pseudocode for this instruction.

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