/* --- First trick: find %$v$% --- */
+retry:
pf.step = 2;
x = mprand(x, pl - ql - 1, r, 1);
x = pgen("v", x, x, ev, ec,
dp->p = sp[1].u.x;
if (!dp->q)
goto fail_1;
+ if (mp_bits(dp->q) != ql || mp_bits(dp->p) != pl) {
+ if (steps) goto fail_1;
+ MP_DROP(dp->p);
+ MP_DROP(dp->q);
+ goto retry;
+ }
/* --- Third trick: find a generator --- */