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Microsoft Specific

The __m128 data type, for use with the Streaming SIMD Extensions and Streaming SIMD Extensions 2 instructions intrinsics, is defined as follows:

// data_types__m128.cpp
typedef struct __declspec(intrin_type) __declspec(align(16)) __m128 {
   float m128_f32[4];
} __m128;

int main()

You should not access the __m128 fields directly. You can, however, see these types in the debugger. A variable of type __m128 maps to the XMM[0-7] registers.

Variables of type _m128 are automatically aligned on 16-byte boundaries.

END Microsoft Specific

See Also

C++ Keywords | Fundamental Types | Data Type Ranges