 static void add_bytes_l2_c(uint8_t *dst, uint8_t *src1, uint8_t *src2, int w)
 {
     long i;
    for (i = 0; i <= w - (int)sizeof(long); i += sizeof(long)) {
         long a = *(long *)(src1 + i);
         long b = *(long *)(src2 + i);
         *(long *)(dst + i) = ((a & pb_7f) + (b & pb_7f)) ^ ((a ^ b) & pb_80);
    }
    for (; i < w; i++)
        dst[i] = src1[i] + src2[i];
}

This weakness involves numeric computation errors, such as integer overflows, underflows, or precision losses, which can lead to miscalculations and exploitable behaviors in software.