transpose_4lane_inline()

void fl::transpose_4lane_inline ( const u8 *const lanes[4], u8 * output, size_t num_bytes )

inline

Low-level bit-interleaving primitive for 4 lanes (ISR-safe)

Transposes 4 input bytes into 4-way interleaved format with direct bit extraction. This function is ISR-safe: no allocations, no exceptions, minimal overhead. Inline functions are automatically placed where needed - no IRAM_ATTR required.

Parameters

lanes	Array of 4 lane byte pointers
output	Output buffer (must have space for num_bytes * 4 bytes)
num_bytes	Number of bytes to transpose per lane

Note

Inline function - inlined at call site (including ISR contexts)

Output size is num_bytes * 4

Examples

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

Definition at line 355 of file transposition.h.

              {
    for (size_t byte_idx = 0; byte_idx < num_bytes; byte_idx++) {
        u8 a = lanes[0][byte_idx];
        u8 b = lanes[1][byte_idx];
        u8 c = lanes[2][byte_idx];
        u8 d = lanes[3][byte_idx];
 
        u8* dest = &output[byte_idx * 4];
 
        dest[0] = ((a >> 7) & 0x01) << 0 | ((b >> 7) & 0x01) << 1 | ((c >> 7) & 0x01) << 2 | ((d >> 7) & 0x01) << 3 |
                  ((a >> 6) & 0x01) << 4 | ((b >> 6) & 0x01) << 5 | ((c >> 6) & 0x01) << 6 | ((d >> 6) & 0x01) << 7;
 
        dest[1] = ((a >> 5) & 0x01) << 0 | ((b >> 5) & 0x01) << 1 | ((c >> 5) & 0x01) << 2 | ((d >> 5) & 0x01) << 3 |
                  ((a >> 4) & 0x01) << 4 | ((b >> 4) & 0x01) << 5 | ((c >> 4) & 0x01) << 6 | ((d >> 4) & 0x01) << 7;
 
        dest[2] = ((a >> 3) & 0x01) << 0 | ((b >> 3) & 0x01) << 1 | ((c >> 3) & 0x01) << 2 | ((d >> 3) & 0x01) << 3 |
                  ((a >> 2) & 0x01) << 4 | ((b >> 2) & 0x01) << 5 | ((c >> 2) & 0x01) << 6 | ((d >> 2) & 0x01) << 7;
 
        dest[3] = ((a >> 1) & 0x01) << 0 | ((b >> 1) & 0x01) << 1 | ((c >> 1) & 0x01) << 2 | ((d >> 1) & 0x01) << 3 |
                  ((a >> 0) & 0x01) << 4 | ((b >> 0) & 0x01) << 5 | ((c >> 0) & 0x01) << 6 | ((d >> 0) & 0x01) << 7;
    }
}

References FL_NOEXCEPT.

Referenced by fl::SPITransposer::transpose4().

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