ccmn

Conditional Compare Negative (Immediate)

CCMN <Wn>, #<imm>, #<nzcv>, <cond>

Compares register with negative immediate if condition is true.

Pseudocode Operation

if ConditionHolds(cond) then temp ← Wn + imm5; N ← temp[31]; Z ← (temp == 0); C ← UnsignedOverflow(Wn, imm5); V ← SignedOverflow(Wn, imm5) else N ← nzcv[3]; Z ← nzcv[2]; C ← nzcv[1]; V ← nzcv[0]

Example

CCMN w1, #16, #nzcv, cond

Encoding

Binary Layout

0

31

0

30

1

29

11010010

28:21

imm5

20:16

cond

15:12

1

11

0

10

Rn

9:5

0

4

nzcv

3:0

 

Format Cond Comp

Opcode 0x3A400800

Extension Base

Operands

• Wn
  Reg
• imm
  Imm
• nzcv
  Flags
• cond
  Condition

Related

Other forms of ccmn

• ccmn Conditional Compare Negative (Immediate 64-bit)
• ccmn Conditional Compare Negative (Register)

More in Base

Reference

View in Arm A64 ISA Reference ↗ Arm A64 ISA

Instruction Forms

Encoding	Instruction		ISA		Bit pattern
0x3A400800	CCMN <Wn>, #<imm>, #<nzcv>, <cond>		A64		0 | 0 | 1 | 11010010 | imm5 | cond | 1 | 0 | Rn | 0 | nzcv
0xBA400800	CCMN <Xn>, #<imm>, #<nzcv>, <cond>		A64		1 | 0 | 1 | 11010010 | imm5 | cond | 1 | 0 | Rn | 0 | nzcv
0x3A400000	CCMN <Wn>, <Wm>, #<nzcv>, <cond>		A64		0 | 0 | 1 | 11010010 | Rm | cond | 0 | 0 | Rn | 0 | nzcv
0xBA400000	CCMN <Xn>, <Xm>, #<nzcv>, <cond>		A64		1 | 0 | 1 | 11010010 | Rm | cond | 0 | 0 | Rn | 0 | nzcv

Description

Conditional Compare Negative (immediate) sets the value of the condition flags to the result of the comparison of a register value and a negated immediate value if the condition is TRUE, and an immediate value otherwise.

Operation

if ConditionHolds(cond) then
    bits(datasize) operand1 = X[n, datasize];
    (-, flags) = AddWithCarry(operand1, imm, '0');
PSTATE.<N,Z,C,V> = flags;