# vpaddd_u64(v128)

> Add Pair of elements (scalar). This instruction adds two vector elements in the source SIMD&FP register and writes the scalar result into the destination SIMD&FP 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. Equivalent instruction: ADDP Dd,Vn.2D

## Definition

* **Type:** Method
* **Namespace:** [Unity.Burst.Intrinsics](/engine/6000.6/script-reference/unity/burst/intrinsics.md)
* **Assembly:** UnityEngine.BurstModule

```csharp
public static ulong vpaddd_u64(v128 a0)
```

### Parameters

**** (\[v128]\(/engine/6000.6/script-reference/unity/burst/intrinsics/v128)): 128-bit vector a0

### Returns

| Type                                                          | Description |
| ------------------------------------------------------------- | ----------- |
| [ulong](https://learn.microsoft.com/dotnet/api/system.uint64) | UInt64      |