Re: Bignum support still broken on powerpc (ping: Jerry James)

Thu, 6 Apr 2006 (10:08 -0600 UTC) Jerry James wrote: > Well, then, I don't understand those compiler warnings at all. They > appear to be claiming that mpz_get_ui() is somehow broken; i.e., that > the function can return without returning a value. If that is true, > then you are fundamentally screwed, because we use that function in > several places. In my version of the headers, the inline version of > that function is defined like this: > > #if defined (__GMP_EXTERN_INLINE) || defined (__GMP_FORCE_mpz_get_ui) > #if ! defined (__GMP_FORCE_mpz_get_ui) > __GMP_EXTERN_INLINE > #endif > unsigned long > mpz_get_ui (mpz_srcptr __gmp_z) __GMP_NOTHROW > { > mp_ptr __gmp_p = __gmp_z->_mp_d; > mp_size_t __gmp_n = __gmp_z->_mp_size; > mp_limb_t __gmp_l = __gmp_p[0]; > if (__GMP_ULONG_MAX <= GMP_NUMB_MASK) > return __gmp_l & (-(mp_limb_t) (__gmp_n != 0)); > #if GMP_NAIL_BITS != 0 /* redundant #if, shuts up compiler warnings */ > else /* happens for nails, but not if LONG_LONG_LIMB */ > { /* assume two limbs are enough to fill an ulong */ > __gmp_n = __GMP_ABS (__gmp_n); > if (__gmp_n <= 1) > return __gmp_l & (-(mp_limb_t) (__gmp_n != 0)); > else > return __gmp_l + (__gmp_p[1] << GMP_NUMB_BITS); > } > #endif > } > #endif > > Hmmmmmm.... If __GMP_ULONG_MAX > GMP_NUMB_MASK and GMP_NAIL_BITS == 0, > that function CAN fall off the end. The comment implies that that can't > happen, but even so, could you compile and run this please and tell me > the results? > > #include <stdio.h> > #include <gmp.h> > > int main() > { > printf ("__GMP_ULONG_MAX == %lu\n", __GMP_ULONG_MAX); > printf ("GMP_NUMB_MASK == %lu\n", GMP_NUMB_MASK); > printf ("GMP_NAIL_BITS == %d\n", GMP_NAIL_BITS); > return 0; > } % gcc -o /tmp/gmptest -I/opt/local/include -L/opt/local/lib ~/scratch/gmptest.c % /tmp/gmptest __GMP_ULONG_MAX == 4294967295 GMP_NUMB_MASK == 4294967295 GMP_NAIL_BITS == 0