/* -*-c-*-
*
- * $Id: gfreduce.c,v 1.5 2004/04/08 01:36:15 mdw Exp $
+ * $Id$
*
* Efficient reduction modulo sparse binary polynomials
*
unsigned long i;
gfreduce_instr *ip;
unsigned f = 0;
- size_t w, ww, wi, wl, ll;
+ size_t w, ww, wi, wl, ll, bb;
/* --- Sort out the easy stuff --- */
wi = DA_LEN(&iv);
f = 0;
ll = 0;
+ bb = MPW_BITS - dw;
for (i = 0, mp_scan(&sc, p); mp_step(&sc) && i < d; i++) {
if (!mp_bit(&sc))
continue;
w = ww;
wi = DA_LEN(&iv);
}
- INSTR(GFRI_LSL, (MPW_BITS + i - d)%MPW_BITS);
- if ((MPW_BITS + i - d)%MPW_BITS)
+ INSTR(GFRI_LSL, (bb + i)%MPW_BITS);
+ if ((bb + i)%MPW_BITS)
f |= f_lsr;
}
wl = DA_LEN(&iv);
y = gfreduce_do(r, t, t);
y = gf_add(y, y, x);
}
- rc = !MP_ISZERO(y);
+ rc = !MP_ZEROP(y);
mp_drop(spare);
mp_drop(y);
return (rc);
z = gf_add(z, z, t);
w = gf_add(w, w, rho);
}
- if (!MP_ISZERO(w))
+ if (!MP_ZEROP(w))
break;
MP_DROP(z);
MP_DROP(w);
mp *spare = (e->f & MP_BURN) ? MP_NEWSEC : MP_NEW;
MP_SHRINK(e);
- if (!MP_LEN(e))
+ MP_COPY(a);
+ if (MP_ZEROP(e))
;
- else if (MP_LEN(e) < EXP_THRESH)
- EXP_SIMPLE(x, a, e);
- else
- EXP_WINDOW(x, a, e);
+ else {
+ if (MP_NEGP(e))
+ a = gf_modinv(a, a, gr->p);
+ if (MP_LEN(e) < EXP_THRESH)
+ EXP_SIMPLE(x, a, e);
+ else
+ EXP_WINDOW(x, a, e);
+ }
mp_drop(d);
+ mp_drop(a);
mp_drop(spare);
return (x);
}