vneg

Vector Negate (Double)

VNEG<c>.F64 <Dd>, <Dm>

Negates double-precision register.

Details

Negates a double-precision floating-point value in the source register and stores the result in the destination register. This is a unary VFP operation that inverts the sign bit of the IEEE 754 double-precision number. No condition flags are affected. Requires VFP extension and executes only in A32 instruction set.

Pseudocode Operation

Dd ← -Dm
FPSCR.NZCV unchanged

Example

VNEG.F64 d0, d2

Encoding

Binary Layout
cond
11101
D
11
0
001
Vd
10
11
0
1
M
0
Vm
 
Format VFP Unary
Opcode 0x0EB10B40
Extension VFP (Float)

Operands

  • Dd
    Destination 64-bit SIMD/FP register
  • Dm
    Second source 64-bit SIMD/FP register

Reference (Arm AArch32 ISA)

Instruction Forms

Encoding Instruction ISA Bit pattern
0xF3B10380 VNEG{<c>}{<q>}.<dt> <Dd>, <Dm> A32 111100111 | D | 11 | size | 01 | Vd | 0 | F | 111 | 0 | M | 0 | Vm
0xF3B103C0 VNEG{<c>}{<q>}.<dt> <Qd>, <Qm> A32 111100111 | D | 11 | size | 01 | Vd | 0 | F | 111 | 1 | M | 0 | Vm
0x0EB10940 VNEG{<c>}{<q>}.F16 <Sd>, <Sm> A32 cond | 11101 | D | 11 | 0 | 001 | Vd | 10 | 01 | 0 | 1 | M | 0 | Vm
0x0EB10A40 VNEG{<c>}{<q>}.F32 <Sd>, <Sm> A32 cond | 11101 | D | 11 | 0 | 001 | Vd | 10 | 10 | 0 | 1 | M | 0 | Vm
0x0EB10B40 VNEG{<c>}{<q>}.F64 <Dd>, <Dm> A32 cond | 11101 | D | 11 | 0 | 001 | Vd | 10 | 11 | 0 | 1 | M | 0 | Vm
0xFFB10380 VNEG{<c>}{<q>}.<dt> <Dd>, <Dm> T32 111111111 | D | 11 | size | 01 | Vd | 0 | F | 111 | 0 | M | 0 | Vm
0xFFB103C0 VNEG{<c>}{<q>}.<dt> <Qd>, <Qm> T32 111111111 | D | 11 | size | 01 | Vd | 0 | F | 111 | 1 | M | 0 | Vm
0xEEB10940 VNEG{<c>}{<q>}.F16 <Sd>, <Sm> T32 111011101 | D | 11 | 0 | 001 | Vd | 10 | 01 | 0 | 1 | M | 0 | Vm
0xEEB10A40 VNEG{<c>}{<q>}.F32 <Sd>, <Sm> T32 111011101 | D | 11 | 0 | 001 | Vd | 10 | 10 | 0 | 1 | M | 0 | Vm
0xEEB10B40 VNEG{<c>}{<q>}.F64 <Dd>, <Dm> T32 111011101 | D | 11 | 0 | 001 | Vd | 10 | 11 | 0 | 1 | M | 0 | Vm

Description

Vector Negate negates each element in a vector, and places the results in a second vector. The floating-point version only inverts the sign bit. Depending on settings in the CPACR, NSACR, HCPTR, and FPEXC registers, and the Security state and PE mode in which the instruction is executed, an attempt to execute the instruction might be undefined, or trapped to Hyp mode. For more information see Enabling Advanced SIMD and floating-point support.

Operation

if ConditionPassed() then
    EncodingSpecificOperations();  CheckAdvSIMDOrVFPEnabled(TRUE, advsimd);
    if advsimd then  // Advanced SIMD instruction
        for r = 0 to regs-1
            for e = 0 to elements-1
                if floating_point then
                    Elem[D[d+r],e,esize] = FPNeg(Elem[D[m+r],e,esize]);
                else
                    result = -SInt(Elem[D[m+r],e,esize]);
                    Elem[D[d+r],e,esize] = result<esize-1:0>;
    else             // VFP instruction
        case esize of
            when 16 S[d] = Zeros(16) : FPNeg(S[m]<15:0>);
            when 32 S[d] = FPNeg(S[m]);
            when 64 D[d] = FPNeg(D[m]);