Calculating 64-Bit Values

Calculating 64-Bit Values

[Jonas Appel]

I hope this is not a really stupid question, but Ive tried some ways
and I'm still not satisfied with my current solution. I have to 
calculate some 64 Bit values, like this:

typedef unsigned long long int64;

int64 val = 0x7c95674beb4000;

the only working way to perform calculation was this:

unsigned int timestamp[2];

timestamp[1] = (unsigned int)((int64)val+0x4324154));
timestamp[0] = (int64)((int64)val+0x4324154)) >> 32;

And printing the value works like this:

printf("Value: %8lx%8lx\n", timestamp[0], timestamp[1]);

Does anyone know a better way to get along with these 64Bit-values?

Thanks in advance,

Jonas

Re: Calculating 64-Bit Values

[Steven Smith]

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> typedef unsigned long long int64;
> 
> int64 val = 0x7c95674beb4000;
Try:

int64 val = 0x7c95674beb4000ll;

gcc won't generate a long long constant unless you explictly tell it
to; it tries to stuff the whole thing into 32 bits, which doesn't
really work.

Incidentally, you might want to pick a different name for your typedef
-- int64 is usually signed.

> And printing the value works like this:
> 
> printf("Value: %8lx%8lx\n", timestamp[0], timestamp[1]);
printf("Value: %llx", timestamp);

should work.  You may need %qx instead of %llx on some really old
systems, or conceivably %Lx.

Steven Smith.

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