adds

Add and Set Flags (Immediate)

ADDS <Wd>, <Wn|Wsp>, #<imm> {, lsl #<shift>}

Adds immediate and updates flags.

Pseudocode Operation

imm_val ← imm12 << (sh * 12)
result ← Wn + imm_val
Wd ← result
N ← result[31]
Z ← (result == 0)
C ← CarryOut(Wn, imm_val)
V ← OverflowFrom(Wn, imm_val)

Example

ADDS w0, Wn, #16

Encoding

Binary Layout

0

31

0

30

1

29

100010

28:23

sh

22

imm12

21:10

Rn

9:5

Rd

4:0

 

Format Data Processing (Immediate)

Opcode 0x31000000

Extension Base

Operands

• Wd
  Destination 32-bit integer register
• Wn
  First source / base 32-bit integer register
• imm
  Imm

Related

Other forms of adds

• adds Add and Set Flags (Extended Register)
• adds Add and Set Flags (Extended Register 64-bit)
• adds Add and Set Flags (Immediate 64-bit)
• adds Add and Set Flags (Shifted Register)
• adds Add and Set Flags (Shifted Register 64-bit)

More in Base

Reference

View in Arm A64 ISA Reference ↗ Arm A64 ISA

Instruction Forms

Encoding	Instruction		ISA		Bit pattern
0x2B200000	ADDS <Wd>, <Wn|WSP>, <Wm>{, <extend> {#<amount>}}		A64		0 | 0 | 1 | 01011 | 00 | 1 | Rm | option | imm3 | Rn | Rd
0xAB200000	ADDS <Xd>, <Xn|SP>, <R><m>{, <extend> {#<amount>}}		A64		1 | 0 | 1 | 01011 | 00 | 1 | Rm | option | imm3 | Rn | Rd
0x31000000	ADDS <Wd>, <Wn|WSP>, #<imm>{, <shift>}		A64		0 | 0 | 1 | 100010 | sh | imm12 | Rn | Rd
0xB1000000	ADDS <Xd>, <Xn|SP>, #<imm>{, <shift>}		A64		1 | 0 | 1 | 100010 | sh | imm12 | Rn | Rd
0x2B000000	ADDS <Wd>, <Wn>, <Wm>{, <shift> #<amount>}		A64		0 | 0 | 1 | 01011 | shift | 0 | Rm | imm6 | Rn | Rd
0xAB000000	ADDS <Xd>, <Xn>, <Xm>{, <shift> #<amount>}		A64		1 | 0 | 1 | 01011 | shift | 0 | Rm | imm6 | Rn | Rd

Description

Add (immediate), setting flags, adds a register value and an optionally-shifted immediate value, and writes the result to the destination register. It updates the condition flags based on the result.

Operation

bits(datasize) result;
bits(datasize) operand1 = if n == 31 then SP[]<datasize-1:0> else X[n, datasize];
bits(4) nzcv;


(result, nzcv) = AddWithCarry(operand1, imm, '0');

PSTATE.<N,Z,C,V> = nzcv;

X[d, datasize] = result;