transpose_2lane_inline()

void fl::transpose_2lane_inline ( const u8 * lane0_byte, const u8 * lane1_byte, u8 * output, size_t num_bytes )

inline

Low-level bit-interleaving primitive for 2 lanes (ISR-safe)

Transposes 2 input bytes into 2-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

lane0_byte	Pointer to lane 0 byte
lane1_byte	Pointer to lane 1 byte
output	Output buffer (must have space for 2 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 * 2

Examples

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

Definition at line 329 of file transposition.h.

              {
    for (size_t byte_idx = 0; byte_idx < num_bytes; byte_idx++) {
        u8 a = lane0_byte[byte_idx];
        u8 b = lane1_byte[byte_idx];
 
        // dest[0] contains bit pairs for positions 7,6,5,4 (MSB first)
        output[byte_idx * 2 + 0] =
            ((a >> 7) & 0x01) << 0 | ((b >> 7) & 0x01) << 1 |
            ((a >> 6) & 0x01) << 2 | ((b >> 6) & 0x01) << 3 |
            ((a >> 5) & 0x01) << 4 | ((b >> 5) & 0x01) << 5 |
            ((a >> 4) & 0x01) << 6 | ((b >> 4) & 0x01) << 7;
 
        // dest[1] contains bit pairs for positions 3,2,1,0 (LSB)
        output[byte_idx * 2 + 1] =
            ((a >> 3) & 0x01) << 0 | ((b >> 3) & 0x01) << 1 |
            ((a >> 2) & 0x01) << 2 | ((b >> 2) & 0x01) << 3 |
            ((a >> 1) & 0x01) << 4 | ((b >> 1) & 0x01) << 5 |
            ((a >> 0) & 0x01) << 6 | ((b >> 0) & 0x01) << 7;
    }
}

References FL_NOEXCEPT.

Referenced by fl::SPITransposer::transpose2().

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