Reading integer internals

[Uros Miletic]

Hi

im having one problem that i couldnt overcome for some time. I need to 
implement some functions that will test integer numbers, and i need to do it 
as effective as possible.
For examle, one of the functions is testing the 1024th bit of an integer 
number. I could use the standard gmp bit functions, but why not simply read 
the 32nd limb (bits per limb are equal to 32 on my system) and then get its 
msb.
I would be gratefull if somebody can explain to me how to access the _mp_d 
field of a standard mpz_t and read individual limbs.

Thanks

Uros