avg16()

LIB8STATIC_ALWAYS_INLINE uint16_t avg16	(	uint16_t	i,
		uint16_t	j )

Calculate an integer average of two unsigned 16-bit integer values (uint16_t), rounded down.

Fractional results are rounded down, e.g. avg16(20,41) = 30

Parameters

i	first value to average
j	second value to average

Returns

mean average of i and j, rounded down

Definition at line 225 of file math8.h.

                                                                {
#if AVG16_C == 1
    // return (uint32_t)((uint32_t)(i) + (uint32_t)(j)) >> 1;
    uint32_t tmp = i;
    tmp += j;
    return static_cast<uint16_t>(tmp >> 1);
#elif AVG16_AVRASM == 1
    asm volatile(
        /* First, add jLo (heh) to iLo, 9th bit overflows into C flag */
        "add %A[i], %A[j]    \n\t"
        /* Now, add C + jHi to iHi, 17th bit overflows into C flag */
        "adc %B[i], %B[j]    \n\t"
        /* Divide iHi by two, moving C flag into high 16th bit, old 9th bit now
           in
           C */
        "ror %B[i]        \n\t"
        /* Divide iLo by two, moving C flag into high 8th bit */
        "ror %A[i]        \n\t"
        : [i] "+r"(i)
        : [j] "r"(j));
    return i;
#else
#error "No implementation for avg16 available."
#endif
}

References LIB8STATIC_ALWAYS_INLINE.