div big

#include "stdint.h"
typedef  uint32_t BN_ULONG;
#  define BN_BITS         64
#  define BN_BYTES        4
#  define BN_BITS2        32
#  define BN_BITS4        16
#  define BN_MASK2        (0xffffffffL)
#  define BN_MASK2l       (0xffff)
#  define BN_MASK2h1      (0xffff8000L)
#  define BN_MASK2h       (0xffff0000L)
#  define BN_TBIT         (0x80000000L)
#  define BN_DEC_CONV     (1000000000L)


#define THIRTY_TWO_BIT 1

int BN_num_bits_word(BN_ULONG l)
{
    static const unsigned char bits[256] = {
        0, 1, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4,
        5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
        6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
        6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
        7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
        7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
        7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
        7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
        8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
        8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
        8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
        8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
        8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
        8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
        8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
        8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
    };

#if defined(SIXTY_FOUR_BIT_LONG)
    if (l & 0xffffffff00000000L) {
        if (l & 0xffff000000000000L) {
            if (l & 0xff00000000000000L) {
                return (bits[(int)(l >> 56)] + 56);
            } else
                return (bits[(int)(l >> 48)] + 48);
        } else {
            if (l & 0x0000ff0000000000L) {
                return (bits[(int)(l >> 40)] + 40);
            } else
                return (bits[(int)(l >> 32)] + 32);
        }
    } else
#else
# ifdef SIXTY_FOUR_BIT
    if (l & 0xffffffff00000000LL) {
        if (l & 0xffff000000000000LL) {
            if (l & 0xff00000000000000LL) {
                return (bits[(int)(l >> 56)] + 56);
            } else
                return (bits[(int)(l >> 48)] + 48);
        } else {
            if (l & 0x0000ff0000000000LL) {
                return (bits[(int)(l >> 40)] + 40);
            } else
                return (bits[(int)(l >> 32)] + 32);
        }
    } else
# endif
#endif
    {
#if defined(THIRTY_TWO_BIT) || defined(SIXTY_FOUR_BIT) || defined(SIXTY_FOUR_BIT_LONG)
        if (l & 0xffff0000L) {
            if (l & 0xff000000L)
                return (bits[(int)(l >> 24L)] + 24);
            else
                return (bits[(int)(l >> 16L)] + 16);
        } else
#endif
        {
#if defined(THIRTY_TWO_BIT) || defined(SIXTY_FOUR_BIT) || defined(SIXTY_FOUR_BIT_LONG)
            if (l & 0xff00L)
                return (bits[(int)(l >> 8)] + 8);
            else
#endif
                return (bits[(int)(l)]);
        }
    }
}

BN_ULONG bn_div_words(BN_ULONG h, BN_ULONG l, BN_ULONG d)
{
    BN_ULONG dh, dl, q, ret = 0, th, tl, t;
    int i, count = 2;

    if (d == 0)
        return (BN_MASK2);

    i = BN_num_bits_word(d);
   // assert((i == BN_BITS2) || (h <= (BN_ULONG)1 << i));

    i = BN_BITS2 - i;
    if (h >= d)
        h -= d;

    if (i) {
        d <<= i;
        h = (h << i) | (l >> (BN_BITS2 - i));
        l <<= i;
    }
    dh = (d & BN_MASK2h) >> BN_BITS4;
    dl = (d & BN_MASK2l);
    for (;;) {
        if ((h >> BN_BITS4) == dh)
            q = BN_MASK2l;
        else
            q = h / dh;

        th = q * dh;
        tl = dl * q;
        for (;;) {
            t = h - th;
            if ((t & BN_MASK2h) ||
                ((tl) <= ((t << BN_BITS4) | ((l & BN_MASK2h) >> BN_BITS4))))
                break;
            q--;
            th -= dh;
            tl -= dl;
        }
        t = (tl >> BN_BITS4);
        tl = (tl << BN_BITS4) & BN_MASK2h;
        th += t;

        if (l < tl)
            th++;
        l -= tl;
        if (h < th) {
            h += d;
            q--;
        }
        h -= th;

        if (--count == 0)
            break;

        ret = q << BN_BITS4;
        h = ((h << BN_BITS4) | (l >> BN_BITS4)) & BN_MASK2;
        l = (l & BN_MASK2l) << BN_BITS4;
    }
    ret |= q;
    return (ret);
}

int cmain(int argc, char *argv[])
{
    uint64_t a = 0xfff0000fffee9ull;
    uint32_t ah = a >> 32;
    uint32_t al = a;
    uint32_t b = 0x1033245full;

    auto r1 = bn_div_words(ah, al, b);
    auto r2 = a / b;

    return 0;
}

int main(int argc, char *argv[])
{
    uint64_t a = 0xf0000001ull << 1;
    uint32_t ah = a >> 32;
    uint32_t al = a;
    uint32_t b = 0xf0000001;
    auto r1 = bn_div_words(ah, al, b);
    return 0;
}