initially checkin

1 files changed, 178 insertions, 0 deletions

diff --git a/mpi/mpi-mul.c b/mpi/mpi-mul.c
new file mode 100644
index 000000000..03f2b4b44
--- /dev/null
+++ b/mpi/mpi-mul.c
@@ -0,0 +1,178 @@
+/* mpi-mul.c  -  MPI functions
+ *	Copyright (c) 1997 by Werner Koch (dd9jn)
+ *
+ * This file is part of G10.
+ *
+ * G10 is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * G10 is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+ */
+
+#include <config.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include "mpi-internal.h"
+
+
+void
+mpi_mul_ui( MPI prod, MPI mult, unsigned long small_mult )
+{
+    mpi_size_t size, prod_size;
+    mpi_ptr_t  prod_ptr;
+    mpi_limb_t cy;
+    int sign;
+
+    size = mult->nlimbs;
+    sign = mult->sign;
+
+    if( !size || !small_mult ) {
+	prod->nlimbs = 0;
+	prod->sign = 0;
+	return;
+    }
+
+    prod_size = size + 1;
+    if( prod->alloced < prod_size )
+	mpi_resize( prod, prod_size );
+    prod_ptr = prod->d;
+
+    cy = mpihelp_mul_1( prod_ptr, mult->d, size, (mpi_limb_t)small_mult );
+    if( cy )
+	prod_ptr[size++] = cy;
+    prod->nlimbs = size;
+    prod->sign = sign;
+}
+
+
+void
+mpi_mul_2exp( MPI w, MPI u, unsigned long cnt)
+{
+    mpi_size_t usize, wsize, limb_cnt;
+    mpi_ptr_t wp;
+    mpi_limb_t wlimb;
+    int usign, wsign;
+
+    usize = u->nlimbs;
+    usign = u->sign;
+
+    if( !usize ) {
+	w->nlimbs = 0;
+	w->sign = 0;
+	return;
+    }
+
+    limb_cnt = cnt / BITS_PER_MPI_LIMB;
+    wsize = usize + limb_cnt + 1;
+    if( w->alloced < wsize )
+	mpi_resize(w, wsize );
+    wp = w->d;
+    wsize = usize + limb_cnt;
+    wsign = usign;
+
+    cnt %= BITS_PER_MPI_LIMB;
+    if( cnt ) {
+	wlimb = mpihelp_lshift( wp + limb_cnt, u->d, usize, cnt );
+	if( wlimb ) {
+	    wp[wsize] = wlimb;
+	    wsize++;
+	}
+    }
+    else {
+	MPN_COPY_DECR( wp + limb_cnt, u->d, usize );
+    }
+
+    /* Zero all whole limbs at low end.  Do it here and not before calling
+     * mpn_lshift, not to lose for U == W.  */
+    MPN_ZERO( wp, limb_cnt );
+
+    w->nlimbs = wsize;
+    w->sign = wsign;
+}
+
+
+
+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, 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;
+	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;
+
+    /* Ensure W has space enough to store the result.  */
+    wsize = usize + vsize;
+    if( w->alloced < wsize ) {
+	if( wp == up || wp == vp ) {
+	    wp = mpi_alloc_limb_space( wsize );
+	    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 );
+	    /* 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 );
+	    /* 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 )
+	mpi_assign_limb_space( w, wp, wsize );
+    w->nlimbs = wsize;
+    w->sign = sign_product;
+    if( tmp_limb )
+	mpi_free_limb_space( tmp_limb );
+}
+
+