Ciao, Il Sab, 15 Febbraio 2014 4:55 pm, Torbjorn Granlund ha scritto: > I traced it to a nn=0 call to the underlying pi1 call. Dunno if that's > problematic.
Yes, that's the problem. When n=1. Code says: if (d & GMP_NUMB_HIGHBIT) { /* Normalized case */ uh = up[--n]; /* Here n goes to 0 */ ... if (BELOW_THRESHOLD (n, DIV_QR_1_NORM_THRESHOLD)) { while (n > 0) udiv_qrnnd (...); return uh; } return mpn_div_qr_1n_pi1 (qp, up, n, uh, d, dinv); } The error arises when DIV_QR_1_NORM_THRESHOLD is zero, and the BELOW_THRESHOLD is unconditionally false, so that the code doesn't simply return uh, but calls mpn_div_qr_1n_pi1 with n = 0... I disallowed zero DIV_QR_1_NORM_THRESHOLD with this patch: https://gmplib.org/repo/gmp/rev/83258bea6f8f and the GMP_CHECK_RANDOMIZE=3526906869 test passes. I believe that we should, for the same reasons, disallow zero DIV_QR_1_UNNORM_THRESHOLD in the /* Unnormalized case */ branch. Regards, m -- http://bodrato.it/papers/ _______________________________________________ gmp-devel mailing list gmp-devel@gmplib.org https://gmplib.org/mailman/listinfo/gmp-devel