Base Instructions | SIMD&FP Instructions | SVE Instructions | SME Instructions | Index by Encoding | Shared Pseudocode | Proprietary Notice

## FNEG (scalar)

Floating-point Negate (scalar). This instruction negates the value in the SIMD&FP source register and writes the result to the SIMD&FP destination register.

Depending on the settings in the CPACR_EL1, CPTR_EL2, and CPTR_EL3 registers, and the current Security state and Exception level, an attempt to execute the instruction might be trapped.

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
0 | 0 | 0 | 1 | 1 | 1 | 1 | 0 | ftype | 1 | 0 | 0 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | 0 | 0 | Rn | Rd
|  |  |  |  |  |  | opc |  |  |

#### Half-precision (ftype == 11)
(FEAT_FP16)

FNEG <Hd>, <Hn>

#### Single-precision (ftype == 00)

FNEG <Sd>, <Sn>

#### Double-precision (ftype == 01)

FNEG <Dd>, <Dn>

integer d = UInt(Rd); integer n = UInt(Rn); integer esize; case ftype of when '00' esize = 32; when '01' esize = 64; when '10' UNDEFINED; when '11' if HaveFP16Ext() then esize = 16; else UNDEFINED;

### Assembler Symbols

<Dd> | Is the 64-bit name of the SIMD&FP destination register, encoded in the "Rd" field.

<Dn> | Is the 64-bit name of the SIMD&FP source register, encoded in the "Rn" field.

<Hd> | Is the 16-bit name of the SIMD&FP destination register, encoded in the "Rd" field.

<Hn> | Is the 16-bit name of the SIMD&FP source register, encoded in the "Rn" field.

<Sd> | Is the 32-bit name of the SIMD&FP destination register, encoded in the "Rd" field.

<Sn> | Is the 32-bit name of the SIMD&FP source register, encoded in the "Rn" field.

### Operation

CheckFPEnabled64(); FPCRType fpcr = FPCR[]; boolean merge = IsMerging(fpcr); bits(128) result = if merge then V[d, 128] else 0<127:0>; bits(esize) operand = V[n, esize]; Elem[result, 0, esize] = FPNeg(operand); V[d, 128] = result;

Base Instructions | SIMD&FP Instructions | SVE Instructions | SME Instructions | Index by Encoding | Shared Pseudocode | Proprietary Notice

Internal version only: isa v33.64, AdvSIMD v29.12, pseudocode v2023-06_rel, sve v2023-06_rel ; Build timestamp: 2023-07-04T19:42

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