A while back, I reverse-engineered a checksum algorithm from an mmo used to check the validity of an item that's linked to chat (similar to WoW). The idea is if the checksum is invalid then the game client would ignore the link when clicked. Otherwise clicking on the item link in in-game chat would display the stat and attrib for that item.

Here's the function I wrote to reproduce the checksum in question. Are there any code smells or readability issues in this code segment? Can any part(s) of it be improved?

ushort16 CreateChecksum(const string &itemlink)
{
    stringstream parseitemlink(itemlink);
    uint32 hexform[ITEMLINKGROUPCOUNT] = {0};
    uint32 hexsum = 0;

    //Parse itemLink string into hexform array
    for (int i = 0; i < ITEMLINKGROUPCOUNT; ++i)
        parseitemlink >> hex >> hexform[i];

    //sum all the itemlink group together
    for (int i = 0; i < ITEMLINKGROUPCOUNT; ++i)
        hexsum += hexform[i];

    for (int i = 0; i < ITEMLINKGROUPCOUNT; ++i)
    {
        uint32 ebx = hexform[i], edi = ebx * i;

        //if loop iteration is odd store MSB 2-bytes.
        //Otherwise, store working hexgroup as is untouched
        if (i & 0x01)
            ebx = hexform[i] >> 16; // aka same as dividing hexform[i] by 65,536

        // (hexform[i] / 65,536) + (hexform[i] * i) + hexsum -- for odd groups
        //  hexform[i] + (hexform[i] * i) + hexsum           -- for even groups
        ebx += edi + hexsum;
        hexsum = ebx ^ hexform[i];
    }

    for (int i = 0; i < ITEMLINKGROUPCOUNT; ++i)
    {
        // the more familiar high-level form would be
        // hexform[i]^2 + hexform[i] * hexsum
        uint32 ecx = (hexform[i] + 1) * hexsum,
               eax = ecx * hexform[i];

        eax >>= 16;
        eax += ecx;
        hexsum = eax ^ hexform[i];
    }

    //return the lower 2-bytes of hexsum
    //as the final checksum
    return hexsum & 0xFFFF;
}//CreateChecksum

Edit: forgot to mention, the format of the itemlink is comprised of a group of hexadecimal separated with a space in string format. It's pass into main() as an argument when the program is run. Here's what a itemlink hex string might look like:

const string EXAMPLELINK = "36c6a 0 3f000a54 d0f1 0 0 0 0 0 0 20d0";