ccmp

Conditional Compare (Immediate)

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

Compares register with immediate if condition is true.

Pseudocode Operation

if ConditionHolds(cond) then temp ← Wn - imm5; N ← temp[31]; Z ← (temp == 0); C ← NOT(BorrowFrom(Wn, imm5)); V ← SignedOverflow(Wn, -imm5) else N ← nzcv[3]; Z ← nzcv[2]; C ← nzcv[1]; V ← nzcv[0]

Example

CCMP w1, #16, #nzcv, cond

Encoding

Binary Layout

0

31

1

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 0x7A400800

Extension Base

Operands

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

Related

Other forms of ccmp

• ccmp Conditional Compare (Register)

More in Base

Reference

View in Arm A64 ISA Reference ↗ Arm A64 ISA

Instruction Forms

Encoding	Instruction		ISA		Bit pattern
0x7A400800	CCMP <Wn>, #<imm>, #<nzcv>, <cond>		A64		0 | 1 | 1 | 11010010 | imm5 | cond | 1 | 0 | Rn | 0 | nzcv
0xFA400800	CCMP <Xn>, #<imm>, #<nzcv>, <cond>		A64		1 | 1 | 1 | 11010010 | imm5 | cond | 1 | 0 | Rn | 0 | nzcv
0x7A400000	CCMP <Wn>, <Wm>, #<nzcv>, <cond>		A64		0 | 1 | 1 | 11010010 | Rm | cond | 0 | 0 | Rn | 0 | nzcv
0xFA400000	CCMP <Xn>, <Xm>, #<nzcv>, <cond>		A64		1 | 1 | 1 | 11010010 | Rm | cond | 0 | 0 | Rn | 0 | nzcv

Description

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

Operation

if ConditionHolds(cond) then
    bits(datasize) operand1 = X[n, datasize];
    bits(datasize) operand2;
    operand2 = NOT(imm);
    (-, flags) = AddWithCarry(operand1, operand2, '1');
PSTATE.<N,Z,C,V> = flags;