# DWORD Multiply Intrinsics

These Intel® Streaming SIMD Extensions (Intel® SSE4) DWORD multiply intrinsics are designed to aid vectorization. They enable four simultaneous 32-bit by 32-bit multiplies. The prototypes for these intrinsics are in the smmintrin.h file.

To use these intrinsics, include the immintrin.h file as follows:

    #include <immintrin.h>

Intrinsic Syntax | Operation | Corresponding Intel® SSE4 Instruction
--- | --- | ---
__m128i _mm_mul_epi32( __m128i a, __m128i b) | Packed integer 32-bit multiplication of two low pairs of operands producing two 64-bit results | `PMULDQ`
__m128i _mm_mullo_epi32( __m128i a, __m128i b) | Packed integer 32-bit multiplication with truncation of upper halves of results | `PMULLD`

Parent topic: Vectorizing Compiler and Media Accelerators