transpose8x1_MSB()

FASTLED_FORCE_INLINE void fl::transpose8x1_MSB	(	unsigned char *	A,
		unsigned char *	B )

Simplified 8x1 bit transpose with MSB-first output.

Based on: https://web.archive.org/web/20190108225554/http://www.hackersdelight.org/hdcodetxt/transpose8.c.txt

Parameters

A	Input array (8 bytes)
B	Output array (8 bytes, transposed MSB-first)

Examples

/home/runner/work/FastLED/FastLED/src/fl/math/transposition.h.

Definition at line 146 of file transposition.h.

                                                                                           {
    fl::u32 x, y, t;
 
    // Load the array and pack it into x and y.
    y = *(fl::u32*)(A);
    x = *(fl::u32*)(A+4);
 
    // pre-transform x
    t = (x ^ (x >> 7)) & 0x00AA00AA;  x = x ^ t ^ (t << 7);
    t = (x ^ (x >>14)) & 0x0000CCCC;  x = x ^ t ^ (t <<14);
 
    // pre-transform y
    t = (y ^ (y >> 7)) & 0x00AA00AA;  y = y ^ t ^ (t << 7);
    t = (y ^ (y >>14)) & 0x0000CCCC;  y = y ^ t ^ (t <<14);
 
    // final transform
    t = (x & 0xF0F0F0F0) | ((y >> 4) & 0x0F0F0F0F);
    y = ((x << 4) & 0xF0F0F0F0) | (y & 0x0F0F0F0F);
    x = t;
 
    B[7] = y; y >>= 8;
    B[6] = y; y >>= 8;
    B[5] = y; y >>= 8;
    B[4] = y;
 
    B[3] = x; x >>= 8;
    B[2] = x; x >>= 8;
    B[1] = x; x >>= 8;
    B[0] = x;
}

References B, FASTLED_FORCE_INLINE, FL_NOEXCEPT, t, x, and y.

Referenced by transpose_8strips().

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