CNEG | Jon's Arm Reference

CNEG

Conditional negate

This instruction returns, in the destination register, the negated value of the source register if the condition is TRUE, and otherwise returns the value of the source register.

This is an alias of CSNEG. This means:

The encodings in this description are named to match the encodings of CSNEG.

The description of CSNEG gives the operational pseudocode, any constrained unpredictable behavior, and any operational information for this instruction.

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
sf	1	0	1	1	0	1	0	1	0	0	Rm					!= 111x				0	1	Rn					Rd
	op	S														cond					o2

32-bit encoding

(sf == 0)

CNEG <Wd>, <Wn>, <invcond>

is equivalent to

CSNEG <Wd>, <Wn>, <Wm>, <cond>

and is the preferred disassembly when Rn == Rm.

64-bit encoding

(sf == 1)

CNEG <Xd>, <Xn>, <invcond>

is equivalent to

CSNEG <Xd>, <Xn>, <Xm>, <cond>

and is the preferred disassembly when Rn == Rm.

Assembler Symbols

<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" and "Rm" fields.

Is one of the standard conditions, excluding AL and NV, encoded with its least significant bit inverted, and encoded in cond:

cond	<invcond>	Description
0000	NE	Maps to <cond> EQ.
0001	EQ	Maps to <cond> NE.
0010	CC	Maps to <cond> CS.
0011	CS	Maps to <cond> CC.
0100	PL	Maps to <cond> MI.
0101	MI	Maps to <cond> PL.
0110	VC	Maps to <cond> VS.
0111	VS	Maps to <cond> VC.
1000	LS	Maps to <cond> HI.
1001	HI	Maps to <cond> LS.
1010	LT	Maps to <cond> GE.
1011	GE	Maps to <cond> LT.
1100	LE	Maps to <cond> GT.
1101	GT	Maps to <cond> LE.

<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" and "Rm" fields.

Operation

The description of CSNEG gives the operational pseudocode for this instruction.

Operational Information

The description of CSNEG gives the operational information for this instruction.

This site is provided as a community resource and is NOT affiliated with nor endorsed by Arm Limited.