CNEG

Conditional Negate 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															cond					o2

32-bit (sf == 0)

CNEG <Wd>, <Wn>, <cond>

is equivalent to

CSNEG <Wd>, <Wn>, <Wn>, invert(<cond>)

and is the preferred disassembly when Rn == Rm.

64-bit (sf == 1)

CNEG <Xd>, <Xn>, <cond>

is equivalent to

CSNEG <Xd>, <Xn>, <Xn>, invert(<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.

<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.

<cond>

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

Operation

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

Operational information

If PSTATE.DIT is 1:

The execution time of this instruction is independent of:
- The values of the data supplied in any of its registers.
- The values of the NZCV flags.
The response of this instruction to asynchronous exceptions does not vary based on:
- The values of the data supplied in any of its registers.
- The values of the NZCV flags.