Пример #1
0
/* This should be made into an inline function in gmp.h.  */
void
mpihelp_mul_n( mpi_ptr_t prodp, mpi_ptr_t up, mpi_ptr_t vp, mpi_size_t size)
{
    int secure;

    if( up == vp ) {
	if( size < KARATSUBA_THRESHOLD )
	    mpih_sqr_n_basecase( prodp, up, size );
	else {
	    mpi_ptr_t tspace;
	    secure = m_is_secure( up );
	    tspace = mpi_alloc_limb_space( 2 * size, secure );
	    mpih_sqr_n( prodp, up, size, tspace );
	    mpi_free_limb_space( tspace );
	}
    }
    else {
	if( size < KARATSUBA_THRESHOLD )
	    mul_n_basecase( prodp, up, vp, size );
	else {
	    mpi_ptr_t tspace;
	    secure = m_is_secure( up ) || m_is_secure( vp );
	    tspace = mpi_alloc_limb_space( 2 * size, secure );
	    mul_n (prodp, up, vp, size, tspace);
	    mpi_free_limb_space( tspace );
	}
    }
}
Пример #2
0
void
mpihelp_mul_karatsuba_case( mpi_ptr_t prodp,
			    mpi_ptr_t up, mpi_size_t usize,
			    mpi_ptr_t vp, mpi_size_t vsize,
			    struct karatsuba_ctx *ctx )
{
    mpi_limb_t cy;

    if( !ctx->tspace || ctx->tspace_size < vsize ) {
	if( ctx->tspace )
	    mpi_free_limb_space( ctx->tspace );
	ctx->tspace = mpi_alloc_limb_space( 2 * vsize,
				       m_is_secure( up ) || m_is_secure( vp ) );
	ctx->tspace_size = vsize;
    }

    MPN_MUL_N_RECURSE( prodp, up, vp, vsize, ctx->tspace );

    prodp += vsize;
    up += vsize;
    usize -= vsize;
    if( usize >= vsize ) {
	if( !ctx->tp || ctx->tp_size < vsize ) {
	    if( ctx->tp )
		mpi_free_limb_space( ctx->tp );
	    ctx->tp = mpi_alloc_limb_space( 2 * vsize, m_is_secure( up )
						      || m_is_secure( vp ) );
	    ctx->tp_size = vsize;
	}

	do {
	    MPN_MUL_N_RECURSE( ctx->tp, up, vp, vsize, ctx->tspace );
	    cy = mpihelp_add_n( prodp, prodp, ctx->tp, vsize );
	    mpihelp_add_1( prodp + vsize, ctx->tp + vsize, vsize, cy );
	    prodp += vsize;
	    up += vsize;
	    usize -= vsize;
	} while( usize >= vsize );
    }

    if( usize ) {
	if( usize < KARATSUBA_THRESHOLD ) {
	    mpihelp_mul( ctx->tspace, vp, vsize, up, usize );
	}
	else {
	    if( !ctx->next ) {
		ctx->next = m_alloc_clear( sizeof *ctx );
	    }
	    mpihelp_mul_karatsuba_case( ctx->tspace,
					vp, vsize,
					up, usize,
					ctx->next );
	}

	cy = mpihelp_add_n( prodp, prodp, ctx->tspace, vsize);
	mpihelp_add_1( prodp + vsize, ctx->tspace + vsize, usize, cy );
    }
}
MPI
mpi_set_opaque( MPI a, void *p, unsigned int len )
{
    if( !a ) {
#ifdef M_DEBUG
	a = mpi_debug_alloc(0,"alloc_opaque");
#else
	a = mpi_alloc(0);
#endif
    }

    if( a->flags & 4 )
	xfree( a->d );
    else {
#ifdef M_DEBUG
	mpi_debug_free_limb_space(a->d, "alloc_opaque");
#else
	mpi_free_limb_space(a->d);
#endif
    }

    a->d = p;
    a->alloced = 0;
    a->nlimbs = 0;
    a->nbits = len;
    a->flags = 4;
    return a;
}
void
mpi_set_secure( MPI a )
{
    mpi_ptr_t ap, bp;

    if( (a->flags & 1) )
	return;
    a->flags |= 1;
    ap = a->d;
    if( !a->nlimbs ) {
	assert(!ap);
	return;
    }
#ifdef M_DEBUG
    bp = mpi_debug_alloc_limb_space( a->nlimbs, 1, "set_secure" );
#else
    bp = mpi_alloc_limb_space( a->nlimbs, 1 );
#endif
    MPN_COPY( bp, ap, a->nlimbs );
    a->d = bp;
#ifdef M_DEBUG
    mpi_debug_free_limb_space(ap, "set_secure");
#else
    mpi_free_limb_space(ap);
#endif
}
void
mpi_assign_limb_space( MPI a, mpi_ptr_t ap, unsigned nlimbs )
{
    mpi_free_limb_space(a->d);
    a->d = ap;
    a->alloced = nlimbs;
}
Пример #6
0
void
mpihelp_release_karatsuba_ctx( struct karatsuba_ctx *ctx )
{
    struct karatsuba_ctx *ctx2;

    if( ctx->tp )
	mpi_free_limb_space( ctx->tp );
    if( ctx->tspace )
	mpi_free_limb_space( ctx->tspace );
    for( ctx=ctx->next; ctx; ctx = ctx2 ) {
	ctx2 = ctx->next;
	if( ctx->tp )
	    mpi_free_limb_space( ctx->tp );
	if( ctx->tspace )
	    mpi_free_limb_space( ctx->tspace );
	m_free( ctx );
    }
}
Пример #7
0
void mpi_free(MPI a)
{
    if (!a)
        return;

    if (a->flags & 4)
        kzfree(a->d);
    else
        mpi_free_limb_space(a->d);

    if (a->flags & ~7)
        pr_info("invalid flag value in mpi\n");
    kfree(a);
}
Пример #8
0
void mpi_free(MPI a)
{
    if (!a)
        return;

    if (a->flags & 4)
        kfree(a->d);
    else {
        mpi_free_limb_space(a->d);
    }

    if (a->flags & ~7 )
        printk("invalid flag value in mpi\n");
    kfree(a);
}
mpi_free( MPI a )
#endif
{
    if( !a )
	return;
    if( DBG_MEMORY )
	log_debug("mpi_free\n" );
    if( a->flags & 4 )
	xfree( a->d );
    else {
#ifdef M_DEBUG
	mpi_debug_free_limb_space(a->d, info);
#else
	mpi_free_limb_space(a->d);
#endif
    }
    if( a->flags & ~7 )
	log_bug("invalid flag value in mpi\n");
    xfree(a);
}
Пример #10
0
void
mpi_mul( MPI w, MPI u, MPI v)
{
    mpi_size_t usize, vsize, wsize;
    mpi_ptr_t up, vp, wp;
    mpi_limb_t cy;
    int usign, vsign, usecure, vsecure, sign_product;
    int assign_wp=0;
    mpi_ptr_t tmp_limb=NULL;


    if( u->nlimbs < v->nlimbs ) { /* Swap U and V. */
	usize = v->nlimbs;
	usign = v->sign;
	usecure = mpi_is_secure(v);
	up    = v->d;
	vsize = u->nlimbs;
	vsign = u->sign;
	vsecure = mpi_is_secure(u);
	vp    = u->d;
    }
    else {
	usize = u->nlimbs;
	usign = u->sign;
	usecure = mpi_is_secure(u);
	up    = u->d;
	vsize = v->nlimbs;
	vsign = v->sign;
	vsecure = mpi_is_secure(v);
	vp    = v->d;
    }
    sign_product = usign ^ vsign;
    wp = w->d;

    /* Ensure W has space enough to store the result.  */
    wsize = usize + vsize;
    if ( !mpi_is_secure (w) && (mpi_is_secure (u) || mpi_is_secure (v)) ) {
        /* w is not allocated in secure space but u or v is.  To make sure
         * that no temporray results are stored in w, we temporary use 
         * a newly allocated limb space for w */
        wp = mpi_alloc_limb_space( wsize, 1 );
        assign_wp = 2; /* mark it as 2 so that we can later copy it back to
                        * mormal memory */
    }
    else if( w->alloced < wsize ) {
	if( wp == up || wp == vp ) {
	    wp = mpi_alloc_limb_space( wsize, mpi_is_secure(w) );
	    assign_wp = 1;
	}
	else {
	    mpi_resize(w, wsize );
	    wp = w->d;
	}
    }
    else { /* Make U and V not overlap with W.	*/
	if( wp == up ) {
	    /* W and U are identical.  Allocate temporary space for U.	*/
	    up = tmp_limb = mpi_alloc_limb_space( usize, usecure  );
	    /* Is V identical too?  Keep it identical with U.  */
	    if( wp == vp )
		vp = up;
	    /* Copy to the temporary space.  */
	    MPN_COPY( up, wp, usize );
	}
	else if( wp == vp ) {
	    /* W and V are identical.  Allocate temporary space for V.	*/
	    vp = tmp_limb = mpi_alloc_limb_space( vsize, vsecure );
	    /* Copy to the temporary space.  */
	    MPN_COPY( vp, wp, vsize );
	}
    }

    if( !vsize )
	wsize = 0;
    else {
	cy = mpihelp_mul( wp, up, usize, vp, vsize );
	wsize -= cy? 0:1;
    }

    if( assign_wp ) {
        if (assign_wp == 2) {
            /* copy the temp wp from secure memory back to normal memory */
	    mpi_ptr_t tmp_wp = mpi_alloc_limb_space (wsize, 0);
	    MPN_COPY (tmp_wp, wp, wsize);
            mpi_free_limb_space (wp);
            wp = tmp_wp;
        }
	mpi_assign_limb_space( w, wp, wsize );
    }
    w->nlimbs = wsize;
    w->sign = sign_product;
    if( tmp_limb )
	mpi_free_limb_space( tmp_limb );
}
Пример #11
0
int mpi_powm(MPI res, MPI base, MPI exp, MPI mod)
{
	mpi_ptr_t mp_marker = NULL, bp_marker = NULL, ep_marker = NULL;
	mpi_ptr_t xp_marker = NULL;
	mpi_ptr_t tspace = NULL;
	mpi_ptr_t rp, ep, mp, bp;
	mpi_size_t esize, msize, bsize, rsize;
	int esign, msign, bsign, rsign;
	mpi_size_t size;
	int mod_shift_cnt;
	int negative_result;
	int assign_rp = 0;
	mpi_size_t tsize = 0;	
	
	int rc = -ENOMEM;

	esize = exp->nlimbs;
	msize = mod->nlimbs;
	size = 2 * msize;
	esign = exp->sign;
	msign = mod->sign;

	rp = res->d;
	ep = exp->d;

	if (!msize)
		return -EINVAL;

	if (!esize) {
		rp[0] = 1;
		res->nlimbs = (msize == 1 && mod->d[0] == 1) ? 0 : 1;
		res->sign = 0;
		goto leave;
	}

	mp = mp_marker = mpi_alloc_limb_space(msize);
	if (!mp)
		goto enomem;
	count_leading_zeros(mod_shift_cnt, mod->d[msize - 1]);
	if (mod_shift_cnt)
		mpihelp_lshift(mp, mod->d, msize, mod_shift_cnt);
	else
		MPN_COPY(mp, mod->d, msize);

	bsize = base->nlimbs;
	bsign = base->sign;
	if (bsize > msize) {	
		bp = bp_marker = mpi_alloc_limb_space(bsize + 1);
		if (!bp)
			goto enomem;
		MPN_COPY(bp, base->d, bsize);
		mpihelp_divrem(bp + msize, 0, bp, bsize, mp, msize);
		bsize = msize;
		MPN_NORMALIZE(bp, bsize);
	} else
		bp = base->d;

	if (!bsize) {
		res->nlimbs = 0;
		res->sign = 0;
		goto leave;
	}

	if (res->alloced < size) {
		if (rp == ep || rp == mp || rp == bp) {
			rp = mpi_alloc_limb_space(size);
			if (!rp)
				goto enomem;
			assign_rp = 1;
		} else {
			if (mpi_resize(res, size) < 0)
				goto enomem;
			rp = res->d;
		}
	} else {		
		if (rp == bp) {
			
			BUG_ON(bp_marker);
			bp = bp_marker = mpi_alloc_limb_space(bsize);
			if (!bp)
				goto enomem;
			MPN_COPY(bp, rp, bsize);
		}
		if (rp == ep) {
			
			ep = ep_marker = mpi_alloc_limb_space(esize);
			if (!ep)
				goto enomem;
			MPN_COPY(ep, rp, esize);
		}
		if (rp == mp) {
			
			BUG_ON(mp_marker);
			mp = mp_marker = mpi_alloc_limb_space(msize);
			if (!mp)
				goto enomem;
			MPN_COPY(mp, rp, msize);
		}
	}

	MPN_COPY(rp, bp, bsize);
	rsize = bsize;
	rsign = bsign;

	{
		mpi_size_t i;
		mpi_ptr_t xp;
		int c;
		mpi_limb_t e;
		mpi_limb_t carry_limb;
		struct karatsuba_ctx karactx;

		xp = xp_marker = mpi_alloc_limb_space(2 * (msize + 1));
		if (!xp)
			goto enomem;

		memset(&karactx, 0, sizeof karactx);
		negative_result = (ep[0] & 1) && base->sign;

		i = esize - 1;
		e = ep[i];
		count_leading_zeros(c, e);
		e = (e << c) << 1;	
		c = BITS_PER_MPI_LIMB - 1 - c;


		for (;;) {
			while (c) {
				mpi_ptr_t tp;
				mpi_size_t xsize;

				
				if (rsize < KARATSUBA_THRESHOLD)
					mpih_sqr_n_basecase(xp, rp, rsize);
				else {
					if (!tspace) {
						tsize = 2 * rsize;
						tspace =
						    mpi_alloc_limb_space(tsize);
						if (!tspace)
							goto enomem;
					} else if (tsize < (2 * rsize)) {
						mpi_free_limb_space(tspace);
						tsize = 2 * rsize;
						tspace =
						    mpi_alloc_limb_space(tsize);
						if (!tspace)
							goto enomem;
					}
					mpih_sqr_n(xp, rp, rsize, tspace);
				}

				xsize = 2 * rsize;
				if (xsize > msize) {
					mpihelp_divrem(xp + msize, 0, xp, xsize,
						       mp, msize);
					xsize = msize;
				}

				tp = rp;
				rp = xp;
				xp = tp;
				rsize = xsize;

				if ((mpi_limb_signed_t) e < 0) {
					
					if (bsize < KARATSUBA_THRESHOLD) {
						mpi_limb_t tmp;
						if (mpihelp_mul
						    (xp, rp, rsize, bp, bsize,
						     &tmp) < 0)
							goto enomem;
					} else {
						if (mpihelp_mul_karatsuba_case
						    (xp, rp, rsize, bp, bsize,
						     &karactx) < 0)
							goto enomem;
					}

					xsize = rsize + bsize;
					if (xsize > msize) {
						mpihelp_divrem(xp + msize, 0,
							       xp, xsize, mp,
							       msize);
						xsize = msize;
					}

					tp = rp;
					rp = xp;
					xp = tp;
					rsize = xsize;
				}
				e <<= 1;
				c--;
			}

			i--;
			if (i < 0)
				break;
			e = ep[i];
			c = BITS_PER_MPI_LIMB;
		}

		if (mod_shift_cnt) {
			carry_limb =
			    mpihelp_lshift(res->d, rp, rsize, mod_shift_cnt);
			rp = res->d;
			if (carry_limb) {
				rp[rsize] = carry_limb;
				rsize++;
			}
		} else {
			MPN_COPY(res->d, rp, rsize);
			rp = res->d;
		}

		if (rsize >= msize) {
			mpihelp_divrem(rp + msize, 0, rp, rsize, mp, msize);
			rsize = msize;
		}

		
		if (mod_shift_cnt)
			mpihelp_rshift(rp, rp, rsize, mod_shift_cnt);
		MPN_NORMALIZE(rp, rsize);

		mpihelp_release_karatsuba_ctx(&karactx);
	}

	if (negative_result && rsize) {
		if (mod_shift_cnt)
			mpihelp_rshift(mp, mp, msize, mod_shift_cnt);
		mpihelp_sub(rp, mp, msize, rp, rsize);
		rsize = msize;
		rsign = msign;
		MPN_NORMALIZE(rp, rsize);
	}
	res->nlimbs = rsize;
	res->sign = rsign;

leave:
	rc = 0;
enomem:
	if (assign_rp)
		mpi_assign_limb_space(res, rp, size);
	if (mp_marker)
		mpi_free_limb_space(mp_marker);
	if (bp_marker)
		mpi_free_limb_space(bp_marker);
	if (ep_marker)
		mpi_free_limb_space(ep_marker);
	if (xp_marker)
		mpi_free_limb_space(xp_marker);
	if (tspace)
		mpi_free_limb_space(tspace);
	return rc;
}
Пример #12
0
/****************
 * RES = BASE ^ EXP mod MOD
 */
int mpi_powm(MPI res, MPI base, MPI exp, MPI mod)
{
	mpi_ptr_t mp_marker = NULL, bp_marker = NULL, ep_marker = NULL;
	mpi_ptr_t xp_marker = NULL;
	mpi_ptr_t tspace = NULL;
	mpi_ptr_t rp, ep, mp, bp;
	mpi_size_t esize, msize, bsize, rsize;
	int esign, msign, bsign, rsign;
	mpi_size_t size;
	int mod_shift_cnt;
	int negative_result;
	int assign_rp = 0;
	mpi_size_t tsize = 0;	/* to avoid compiler warning */
	/* fixme: we should check that the warning is void */
	int rc = -ENOMEM;

	esize = exp->nlimbs;
	msize = mod->nlimbs;
	size = 2 * msize;
	esign = exp->sign;
	msign = mod->sign;

	rp = res->d;
	ep = exp->d;

	if (!msize)
		return -EINVAL;

	if (!esize) {
		/* Exponent is zero, result is 1 mod MOD, i.e., 1 or 0
		 * depending on if MOD equals 1.  */
		rp[0] = 1;
		res->nlimbs = (msize == 1 && mod->d[0] == 1) ? 0 : 1;
		res->sign = 0;
		goto leave;
	}

	/* Normalize MOD (i.e. make its most significant bit set) as required by
	 * mpn_divrem.  This will make the intermediate values in the calculation
	 * slightly larger, but the correct result is obtained after a final
	 * reduction using the original MOD value.  */
	mp = mp_marker = mpi_alloc_limb_space(msize);
	if (!mp)
		goto enomem;
	count_leading_zeros(mod_shift_cnt, mod->d[msize - 1]);
	if (mod_shift_cnt)
		mpihelp_lshift(mp, mod->d, msize, mod_shift_cnt);
	else
		MPN_COPY(mp, mod->d, msize);

	bsize = base->nlimbs;
	bsign = base->sign;
	if (bsize > msize) {	/* The base is larger than the module. Reduce it. */
		/* Allocate (BSIZE + 1) with space for remainder and quotient.
		 * (The quotient is (bsize - msize + 1) limbs.)  */
		bp = bp_marker = mpi_alloc_limb_space(bsize + 1);
		if (!bp)
			goto enomem;
		MPN_COPY(bp, base->d, bsize);
		/* We don't care about the quotient, store it above the remainder,
		 * at BP + MSIZE.  */
		mpihelp_divrem(bp + msize, 0, bp, bsize, mp, msize);
		bsize = msize;
		/* Canonicalize the base, since we are going to multiply with it
		 * quite a few times.  */
		MPN_NORMALIZE(bp, bsize);
	} else
		bp = base->d;

	if (!bsize) {
		res->nlimbs = 0;
		res->sign = 0;
		goto leave;
	}

	if (res->alloced < size) {
		/* We have to allocate more space for RES.  If any of the input
		 * parameters are identical to RES, defer deallocation of the old
		 * space.  */
		if (rp == ep || rp == mp || rp == bp) {
			rp = mpi_alloc_limb_space(size);
			if (!rp)
				goto enomem;
			assign_rp = 1;
		} else {
			if (mpi_resize(res, size) < 0)
				goto enomem;
			rp = res->d;
		}
	} else {		/* Make BASE, EXP and MOD not overlap with RES.  */
		if (rp == bp) {
			/* RES and BASE are identical.  Allocate temp. space for BASE.  */
			BUG_ON(bp_marker);
			bp = bp_marker = mpi_alloc_limb_space(bsize);
			if (!bp)
				goto enomem;
			MPN_COPY(bp, rp, bsize);
		}
		if (rp == ep) {
			/* RES and EXP are identical.  Allocate temp. space for EXP.  */
			ep = ep_marker = mpi_alloc_limb_space(esize);
			if (!ep)
				goto enomem;
			MPN_COPY(ep, rp, esize);
		}
		if (rp == mp) {
			/* RES and MOD are identical.  Allocate temporary space for MOD. */
			BUG_ON(mp_marker);
			mp = mp_marker = mpi_alloc_limb_space(msize);
			if (!mp)
				goto enomem;
			MPN_COPY(mp, rp, msize);
		}
	}

	MPN_COPY(rp, bp, bsize);
	rsize = bsize;
	rsign = bsign;

	{
		mpi_size_t i;
		mpi_ptr_t xp;
		int c;
		mpi_limb_t e;
		mpi_limb_t carry_limb;
		struct karatsuba_ctx karactx;

		xp = xp_marker = mpi_alloc_limb_space(2 * (msize + 1));
		if (!xp)
			goto enomem;

		memset(&karactx, 0, sizeof karactx);
		negative_result = (ep[0] & 1) && base->sign;

		i = esize - 1;
		e = ep[i];
		count_leading_zeros(c, e);
		e = (e << c) << 1;	/* shift the exp bits to the left, lose msb */
		c = BITS_PER_MPI_LIMB - 1 - c;

		/* Main loop.
		 *
		 * Make the result be pointed to alternately by XP and RP.  This
		 * helps us avoid block copying, which would otherwise be necessary
		 * with the overlap restrictions of mpihelp_divmod. With 50% probability
		 * the result after this loop will be in the area originally pointed
		 * by RP (==RES->d), and with 50% probability in the area originally
		 * pointed to by XP.
		 */

		for (;;) {
			while (c) {
				mpi_ptr_t tp;
				mpi_size_t xsize;

				/*if (mpihelp_mul_n(xp, rp, rp, rsize) < 0) goto enomem */
				if (rsize < KARATSUBA_THRESHOLD)
					mpih_sqr_n_basecase(xp, rp, rsize);
				else {
					if (!tspace) {
						tsize = 2 * rsize;
						tspace =
						    mpi_alloc_limb_space(tsize);
						if (!tspace)
							goto enomem;
					} else if (tsize < (2 * rsize)) {
						mpi_free_limb_space(tspace);
						tsize = 2 * rsize;
						tspace =
						    mpi_alloc_limb_space(tsize);
						if (!tspace)
							goto enomem;
					}
					mpih_sqr_n(xp, rp, rsize, tspace);
				}

				xsize = 2 * rsize;
				if (xsize > msize) {
					mpihelp_divrem(xp + msize, 0, xp, xsize,
						       mp, msize);
					xsize = msize;
				}

				tp = rp;
				rp = xp;
				xp = tp;
				rsize = xsize;

				if ((mpi_limb_signed_t) e < 0) {
					/*mpihelp_mul( xp, rp, rsize, bp, bsize ); */
					if (bsize < KARATSUBA_THRESHOLD) {
						mpi_limb_t tmp;
						if (mpihelp_mul
						    (xp, rp, rsize, bp, bsize,
						     &tmp) < 0)
							goto enomem;
					} else {
						if (mpihelp_mul_karatsuba_case
						    (xp, rp, rsize, bp, bsize,
						     &karactx) < 0)
							goto enomem;
					}

					xsize = rsize + bsize;
					if (xsize > msize) {
						mpihelp_divrem(xp + msize, 0,
							       xp, xsize, mp,
							       msize);
						xsize = msize;
					}

					tp = rp;
					rp = xp;
					xp = tp;
					rsize = xsize;
				}
				e <<= 1;
				c--;
			}

			i--;
			if (i < 0)
				break;
			e = ep[i];
			c = BITS_PER_MPI_LIMB;
		}

		/* We shifted MOD, the modulo reduction argument, left MOD_SHIFT_CNT
		 * steps.  Adjust the result by reducing it with the original MOD.
		 *
		 * Also make sure the result is put in RES->d (where it already
		 * might be, see above).
		 */
		if (mod_shift_cnt) {
			carry_limb =
			    mpihelp_lshift(res->d, rp, rsize, mod_shift_cnt);
			rp = res->d;
			if (carry_limb) {
				rp[rsize] = carry_limb;
				rsize++;
			}
		} else {
			MPN_COPY(res->d, rp, rsize);
			rp = res->d;
		}

		if (rsize >= msize) {
			mpihelp_divrem(rp + msize, 0, rp, rsize, mp, msize);
			rsize = msize;
		}

		/* Remove any leading zero words from the result.  */
		if (mod_shift_cnt)
			mpihelp_rshift(rp, rp, rsize, mod_shift_cnt);
		MPN_NORMALIZE(rp, rsize);

		mpihelp_release_karatsuba_ctx(&karactx);
	}

	if (negative_result && rsize) {
		if (mod_shift_cnt)
			mpihelp_rshift(mp, mp, msize, mod_shift_cnt);
		mpihelp_sub(rp, mp, msize, rp, rsize);
		rsize = msize;
		rsign = msign;
		MPN_NORMALIZE(rp, rsize);
	}
	res->nlimbs = rsize;
	res->sign = rsign;

leave:
	rc = 0;
enomem:
	if (assign_rp)
		mpi_assign_limb_space(res, rp, size);
	if (mp_marker)
		mpi_free_limb_space(mp_marker);
	if (bp_marker)
		mpi_free_limb_space(bp_marker);
	if (ep_marker)
		mpi_free_limb_space(ep_marker);
	if (xp_marker)
		mpi_free_limb_space(xp_marker);
	if (tspace)
		mpi_free_limb_space(tspace);
	return rc;
}
Пример #13
0
int mpi_mul(MPI w, MPI u, MPI v)
{
	int rc = -ENOMEM;
	mpi_size_t usize, vsize, wsize;
	mpi_ptr_t up, vp, wp;
	mpi_limb_t cy;
	int usign, vsign, sign_product;
	int assign_wp = 0;
	mpi_ptr_t tmp_limb = NULL;

	if (u->nlimbs < v->nlimbs) {	/*               */
		usize = v->nlimbs;
		usign = v->sign;
		up = v->d;
		vsize = u->nlimbs;
		vsign = u->sign;
		vp = u->d;
	} else {
		usize = u->nlimbs;
		usign = u->sign;
		up = u->d;
		vsize = v->nlimbs;
		vsign = v->sign;
		vp = v->d;
	}
	sign_product = usign ^ vsign;
	wp = w->d;

	/*                                                 */
	wsize = usize + vsize;
	if (w->alloced < (size_t) wsize) {
		if (wp == up || wp == vp) {
			wp = mpi_alloc_limb_space(wsize);
			if (!wp)
				goto nomem;
			assign_wp = 1;
		} else {
			if (mpi_resize(w, wsize) < 0)
				goto nomem;
			wp = w->d;
		}
	} else {		/*                                       */
		if (wp == up) {
			/*                                                              */
			up = tmp_limb = mpi_alloc_limb_space(usize);
			if (!up)
				goto nomem;
			/*                                                 */
			if (wp == vp)
				vp = up;
			/*                               */
			MPN_COPY(up, wp, usize);
		} else if (wp == vp) {
			/*                                                              */
			vp = tmp_limb = mpi_alloc_limb_space(vsize);
			if (!vp)
				goto nomem;
			/*                               */
			MPN_COPY(vp, wp, vsize);
		}
	}

	if (!vsize)
		wsize = 0;
	else {
		if (mpihelp_mul(wp, up, usize, vp, vsize, &cy) < 0)
			goto nomem;
		wsize -= cy ? 0 : 1;
	}

	if (assign_wp)
		mpi_assign_limb_space(w, wp, wsize);

	w->nlimbs = wsize;
	w->sign = sign_product;
	rc = 0;
nomem:
	if (tmp_limb)
		mpi_free_limb_space(tmp_limb);
	return rc;
}
Пример #14
0
int
mpi_tdiv_qr( MPI quot, MPI rem, MPI num, MPI den)
{
	int rc = -ENOMEM;
	mpi_ptr_t np, dp;
	mpi_ptr_t qp, rp;
	mpi_size_t nsize = num->nlimbs;
	mpi_size_t dsize = den->nlimbs;
	mpi_size_t qsize, rsize;
	mpi_size_t sign_remainder = num->sign;
	mpi_size_t sign_quotient = num->sign ^ den->sign;
	unsigned normalization_steps;
	mpi_limb_t q_limb;
	mpi_ptr_t marker[5];
	int markidx=0;

	memset(marker,0,sizeof(marker));

	/* Ensure space is enough for quotient and remainder.
	 * We need space for an extra limb in the remainder, because it's
	 * up-shifted (normalized) below.  */
	rsize = nsize + 1;
	if (mpi_resize( rem, rsize) < 0) goto nomem;

	qsize = rsize - dsize;	  /* qsize cannot be bigger than this.	*/
	if( qsize <= 0 ) {
		if( num != rem ) {
			rem->nlimbs = num->nlimbs;
			rem->sign = num->sign;
			MPN_COPY(rem->d, num->d, nsize);
		}
		if( quot ) {
			/* This needs to follow the assignment to rem, in case the
			 * numerator and quotient are the same.  */
			quot->nlimbs = 0;
			quot->sign = 0;
		}
		return 0;
	}

	if( quot )
		if (mpi_resize( quot, qsize) < 0) goto nomem;

	/* Read pointers here, when reallocation is finished.  */
	np = num->d;
	dp = den->d;
	rp = rem->d;

	/* Optimize division by a single-limb divisor.  */
	if( dsize == 1 ) {
		mpi_limb_t rlimb;
		if( quot ) {
			qp = quot->d;
			rlimb = mpihelp_divmod_1( qp, np, nsize, dp[0] );
			qsize -= qp[qsize - 1] == 0;
			quot->nlimbs = qsize;
			quot->sign = sign_quotient;
		}
		else
			rlimb = mpihelp_mod_1( np, nsize, dp[0] );
		rp[0] = rlimb;
		rsize = rlimb != 0?1:0;
		rem->nlimbs = rsize;
		rem->sign = sign_remainder;
		return 0;
	}


	if( quot ) {
		qp = quot->d;
		/* Make sure QP and NP point to different objects.  Otherwise the
		 * numerator would be gradually overwritten by the quotient limbs.  */
		if(qp == np) { /* Copy NP object to temporary space.  */
			np = marker[markidx++] = mpi_alloc_limb_space(nsize);
			MPN_COPY(np, qp, nsize);
		}
	}
	else /* Put quotient at top of remainder. */
		qp = rp + dsize;

	count_leading_zeros( normalization_steps, dp[dsize - 1] );

	/* Normalize the denominator, i.e. make its most significant bit set by
	 * shifting it NORMALIZATION_STEPS bits to the left.  Also shift the
	 * numerator the same number of steps (to keep the quotient the same!).
	 */
	if( normalization_steps ) {
		mpi_ptr_t tp;
		mpi_limb_t nlimb;

		/* Shift up the denominator setting the most significant bit of
		 * the most significant word.  Use temporary storage not to clobber
		 * the original contents of the denominator.  */
		tp = marker[markidx++] = mpi_alloc_limb_space(dsize);
		if (!tp) goto nomem;
		mpihelp_lshift( tp, dp, dsize, normalization_steps );
		dp = tp;

		/* Shift up the numerator, possibly introducing a new most
		 * significant word.  Move the shifted numerator in the remainder
		 * meanwhile.  */
		nlimb = mpihelp_lshift(rp, np, nsize, normalization_steps);
		if( nlimb ) {
			rp[nsize] = nlimb;
			rsize = nsize + 1;
		}
		else
			rsize = nsize;
	}
	else {
		/* The denominator is already normalized, as required.	Copy it to
		 * temporary space if it overlaps with the quotient or remainder.  */
		if( dp == rp || (quot && (dp == qp))) {
			mpi_ptr_t tp;

			tp = marker[markidx++] = mpi_alloc_limb_space(dsize);
			if (!tp) goto nomem;
			MPN_COPY( tp, dp, dsize );
			dp = tp;
		}

		/* Move the numerator to the remainder.  */
		if( rp != np )
			MPN_COPY(rp, np, nsize);

		rsize = nsize;
	}

	q_limb = mpihelp_divrem( qp, 0, rp, rsize, dp, dsize );

	if( quot ) {
		qsize = rsize - dsize;
		if(q_limb) {
			qp[qsize] = q_limb;
			qsize += 1;
		}

		quot->nlimbs = qsize;
		quot->sign = sign_quotient;
	}

	rsize = dsize;
	MPN_NORMALIZE (rp, rsize);

	if( normalization_steps && rsize ) {
		mpihelp_rshift(rp, rp, rsize, normalization_steps);
		rsize -= rp[rsize - 1] == 0?1:0;
	}

	rem->nlimbs = rsize;
	rem->sign	= sign_remainder;

	rc = 0;
 nomem:
	while( markidx )
		mpi_free_limb_space(marker[--markidx]);
	return rc;
}