inline void FFTInterleaved()

in XDSP/XDSP.h [711:776]
61 lines of code
13 McCabe index (conditional complexity)

    inline void FFTInterleaved(
        _Inout_updates_(((1 << uLog2Length) * uChannelCount) / 4) XMVECTOR* __restrict pReal,
        _Out_writes_(((1 << uLog2Length) * uChannelCount) / 4) XMVECTOR* __restrict pImaginary,
        _In_reads_(1 << uLog2Length) const XMVECTOR* __restrict pUnityTable,
        _In_ const size_t uChannelCount,
        _In_ const size_t uLog2Length) noexcept
    {
        assert(pReal);
        assert(pImaginary);
        assert(pUnityTable);
        assert(reinterpret_cast<uintptr_t>(pReal) % 16 == 0);
        assert(reinterpret_cast<uintptr_t>(pImaginary) % 16 == 0);
        assert(reinterpret_cast<uintptr_t>(pUnityTable) % 16 == 0);
        assert(uChannelCount > 0 && uChannelCount <= 6);
        assert(uLog2Length >= 2 && uLog2Length <= 9);

        XMVECTOR vRealTemp[768];
        XMVECTOR vImaginaryTemp[768];
        const size_t uLength = size_t(1) << uLog2Length;

        if (uChannelCount > 1)
        {
            Deinterleave(vRealTemp, pReal, uChannelCount, uLength);
        }
        else
        {
            memcpy_s(vRealTemp, sizeof(vRealTemp), pReal, (uLength >> 2) * sizeof(XMVECTOR));
        }

        memset(vImaginaryTemp, 0, (uChannelCount * (uLength >> 2)) * sizeof(XMVECTOR));

        if (uLength > 16)
        {
            for (size_t uChannel = 0; uChannel < uChannelCount; ++uChannel)
            {
                FFT(&vRealTemp[uChannel * (uLength >> 2)], &vImaginaryTemp[uChannel * (uLength >> 2)], pUnityTable, uLength);
            }
        }
        else if (uLength == 16)
        {
            for (size_t uChannel = 0; uChannel < uChannelCount; ++uChannel)
            {
                FFT16(&vRealTemp[uChannel * (uLength >> 2)], &vImaginaryTemp[uChannel * (uLength >> 2)]);
            }
        }
        else if (uLength == 8)
        {
            for (size_t uChannel = 0; uChannel < uChannelCount; ++uChannel)
            {
                FFT8(&vRealTemp[uChannel * (uLength >> 2)], &vImaginaryTemp[uChannel * (uLength >> 2)]);
            }
        }
        else if (uLength == 4)
        {
            for (size_t uChannel = 0; uChannel < uChannelCount; ++uChannel)
            {
                FFT4(&vRealTemp[uChannel * (uLength >> 2)], &vImaginaryTemp[uChannel * (uLength >> 2)]);
            }
        }

        for (size_t uChannel = 0; uChannel < uChannelCount; ++uChannel)
        {
            FFTUnswizzle(&pReal[uChannel * (uLength >> 2)], &vRealTemp[uChannel * (uLength >> 2)], uLog2Length);
            FFTUnswizzle(&pImaginary[uChannel * (uLength >> 2)], &vImaginaryTemp[uChannel * (uLength >> 2)], uLog2Length);
        }
    }