微软xna数学库里的实现

XMFINLINE XMVECTOR XMVector2Cross
(
    FXMVECTOR V1,
    FXMVECTOR V2
)
{
#if defined(_XM_NO_INTRINSICS_)
    FLOAT fCross = (V1.vector4_f32[0] * V2.vector4_f32[1]) - (V1.vector4_f32[1] * V2.vector4_f32[0]);
    XMVECTOR vResult = {
        fCross,
        fCross,
        fCross,
        fCross
    };
    return vResult;
#elif defined(_XM_SSE_INTRINSICS_)
    // Swap x and y
    XMVECTOR vResult = _mm_shuffle_ps(V2,V2,_MM_SHUFFLE(0,1,0,1));
    // Perform the muls
    vResult = _mm_mul_ps(vResult,V1);
    // Splat y
    XMVECTOR vTemp = _mm_shuffle_ps(vResult,vResult,_MM_SHUFFLE(1,1,1,1));
    // Sub the values
    vResult = _mm_sub_ss(vResult,vTemp);
    // Splat the cross product
    vResult = _mm_shuffle_ps(vResult,vResult,_MM_SHUFFLE(0,0,0,0));
        return vResult;
#else // _XM_VMX128_INTRINSICS_
#endif // _XM_VMX128_INTRINSICS_
}

【 在 xibaomo (xibaomo) 的大作中提到: 】
: 有个非常简单的函数，都是float，
: float cross(Complex& a, Complex& b) {
:         float tmp= a.re*b.im - a.im*b.re;
: ...................
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