64bit number to 16bit number

[DavidDobson]

Hi Everyone

I have a 64bit mac address that I want to convert to a 16bit short address (by taking the last 4 numbers from the end of the mac:

MAC: 0xAAAAAAAAAAAAABCD

SHORT: ABCD

I have tried the obvious with:

int main()
{
    uint64_t macAddress = 0xABCDEF0123456789;
    uint16_t shortAddress = 0x0000;
    shortAddress = macAddress;
    printf("Short address is: %02X \n", shortAddress);
    return 0;
}

Which works, but I get a compiler warning:

Integer constant is to large for long type

Can anyone suggest another way of doing it that will result in no compiler warnings?

Many thanks

David

[matsp]

Seems to me that your uint64_t is not defined correctly, or you need to postfix the number with LL as "long long".

You probably also should have a cast on the shortAddress = macAddress; line, so that the compiler realizes that you are willingly loosing precision.

--
Mats

[DavidDobson]

ah! that did it! - Thanks

int main()
{
    uint64_t macAddress = 0xABCDEF0123456789LL;
    uint16_t shortAddress = 0x0000;
    shortAddress = (uint16_t)macAddress;
    printf("SHort address is: %02X \n", shortAddress);
    return 0;
}