summaryrefslogtreecommitdiffstats
path: root/libtommath/bn_mp_toom_sqr.c
diff options
context:
space:
mode:
authorKevin B Kenny <kennykb@acm.org>2005-01-19 22:41:26 (GMT)
committerKevin B Kenny <kennykb@acm.org>2005-01-19 22:41:26 (GMT)
commitef78ca64ce6ba6a8786f083318fe536f2bd52925 (patch)
tree47f8ad0d7291237c7f9af988c5e05275ed9286ee /libtommath/bn_mp_toom_sqr.c
parentb23d942a1e86ddee18c2309afd7fa7e9afa79ef8 (diff)
downloadtcl-ef78ca64ce6ba6a8786f083318fe536f2bd52925.zip
tcl-ef78ca64ce6ba6a8786f083318fe536f2bd52925.tar.gz
tcl-ef78ca64ce6ba6a8786f083318fe536f2bd52925.tar.bz2
Import of libtommath 0.33
Diffstat (limited to 'libtommath/bn_mp_toom_sqr.c')
-rw-r--r--libtommath/bn_mp_toom_sqr.c222
1 files changed, 222 insertions, 0 deletions
diff --git a/libtommath/bn_mp_toom_sqr.c b/libtommath/bn_mp_toom_sqr.c
new file mode 100644
index 0000000..8c46fea
--- /dev/null
+++ b/libtommath/bn_mp_toom_sqr.c
@@ -0,0 +1,222 @@
+#include <tommath.h>
+#ifdef BN_MP_TOOM_SQR_C
+/* LibTomMath, multiple-precision integer library -- Tom St Denis
+ *
+ * LibTomMath is a library that provides multiple-precision
+ * integer arithmetic as well as number theoretic functionality.
+ *
+ * The library was designed directly after the MPI library by
+ * Michael Fromberger but has been written from scratch with
+ * additional optimizations in place.
+ *
+ * The library is free for all purposes without any express
+ * guarantee it works.
+ *
+ * Tom St Denis, tomstdenis@iahu.ca, http://math.libtomcrypt.org
+ */
+
+/* squaring using Toom-Cook 3-way algorithm */
+int
+mp_toom_sqr(mp_int *a, mp_int *b)
+{
+ mp_int w0, w1, w2, w3, w4, tmp1, a0, a1, a2;
+ int res, B;
+
+ /* init temps */
+ if ((res = mp_init_multi(&w0, &w1, &w2, &w3, &w4, &a0, &a1, &a2, &tmp1, NULL)) != MP_OKAY) {
+ return res;
+ }
+
+ /* B */
+ B = a->used / 3;
+
+ /* a = a2 * B**2 + a1 * B + a0 */
+ if ((res = mp_mod_2d(a, DIGIT_BIT * B, &a0)) != MP_OKAY) {
+ goto ERR;
+ }
+
+ if ((res = mp_copy(a, &a1)) != MP_OKAY) {
+ goto ERR;
+ }
+ mp_rshd(&a1, B);
+ mp_mod_2d(&a1, DIGIT_BIT * B, &a1);
+
+ if ((res = mp_copy(a, &a2)) != MP_OKAY) {
+ goto ERR;
+ }
+ mp_rshd(&a2, B*2);
+
+ /* w0 = a0*a0 */
+ if ((res = mp_sqr(&a0, &w0)) != MP_OKAY) {
+ goto ERR;
+ }
+
+ /* w4 = a2 * a2 */
+ if ((res = mp_sqr(&a2, &w4)) != MP_OKAY) {
+ goto ERR;
+ }
+
+ /* w1 = (a2 + 2(a1 + 2a0))**2 */
+ if ((res = mp_mul_2(&a0, &tmp1)) != MP_OKAY) {
+ goto ERR;
+ }
+ if ((res = mp_add(&tmp1, &a1, &tmp1)) != MP_OKAY) {
+ goto ERR;
+ }
+ if ((res = mp_mul_2(&tmp1, &tmp1)) != MP_OKAY) {
+ goto ERR;
+ }
+ if ((res = mp_add(&tmp1, &a2, &tmp1)) != MP_OKAY) {
+ goto ERR;
+ }
+
+ if ((res = mp_sqr(&tmp1, &w1)) != MP_OKAY) {
+ goto ERR;
+ }
+
+ /* w3 = (a0 + 2(a1 + 2a2))**2 */
+ if ((res = mp_mul_2(&a2, &tmp1)) != MP_OKAY) {
+ goto ERR;
+ }
+ if ((res = mp_add(&tmp1, &a1, &tmp1)) != MP_OKAY) {
+ goto ERR;
+ }
+ if ((res = mp_mul_2(&tmp1, &tmp1)) != MP_OKAY) {
+ goto ERR;
+ }
+ if ((res = mp_add(&tmp1, &a0, &tmp1)) != MP_OKAY) {
+ goto ERR;
+ }
+
+ if ((res = mp_sqr(&tmp1, &w3)) != MP_OKAY) {
+ goto ERR;
+ }
+
+
+ /* w2 = (a2 + a1 + a0)**2 */
+ if ((res = mp_add(&a2, &a1, &tmp1)) != MP_OKAY) {
+ goto ERR;
+ }
+ if ((res = mp_add(&tmp1, &a0, &tmp1)) != MP_OKAY) {
+ goto ERR;
+ }
+ if ((res = mp_sqr(&tmp1, &w2)) != MP_OKAY) {
+ goto ERR;
+ }
+
+ /* now solve the matrix
+
+ 0 0 0 0 1
+ 1 2 4 8 16
+ 1 1 1 1 1
+ 16 8 4 2 1
+ 1 0 0 0 0
+
+ using 12 subtractions, 4 shifts, 2 small divisions and 1 small multiplication.
+ */
+
+ /* r1 - r4 */
+ if ((res = mp_sub(&w1, &w4, &w1)) != MP_OKAY) {
+ goto ERR;
+ }
+ /* r3 - r0 */
+ if ((res = mp_sub(&w3, &w0, &w3)) != MP_OKAY) {
+ goto ERR;
+ }
+ /* r1/2 */
+ if ((res = mp_div_2(&w1, &w1)) != MP_OKAY) {
+ goto ERR;
+ }
+ /* r3/2 */
+ if ((res = mp_div_2(&w3, &w3)) != MP_OKAY) {
+ goto ERR;
+ }
+ /* r2 - r0 - r4 */
+ if ((res = mp_sub(&w2, &w0, &w2)) != MP_OKAY) {
+ goto ERR;
+ }
+ if ((res = mp_sub(&w2, &w4, &w2)) != MP_OKAY) {
+ goto ERR;
+ }
+ /* r1 - r2 */
+ if ((res = mp_sub(&w1, &w2, &w1)) != MP_OKAY) {
+ goto ERR;
+ }
+ /* r3 - r2 */
+ if ((res = mp_sub(&w3, &w2, &w3)) != MP_OKAY) {
+ goto ERR;
+ }
+ /* r1 - 8r0 */
+ if ((res = mp_mul_2d(&w0, 3, &tmp1)) != MP_OKAY) {
+ goto ERR;
+ }
+ if ((res = mp_sub(&w1, &tmp1, &w1)) != MP_OKAY) {
+ goto ERR;
+ }
+ /* r3 - 8r4 */
+ if ((res = mp_mul_2d(&w4, 3, &tmp1)) != MP_OKAY) {
+ goto ERR;
+ }
+ if ((res = mp_sub(&w3, &tmp1, &w3)) != MP_OKAY) {
+ goto ERR;
+ }
+ /* 3r2 - r1 - r3 */
+ if ((res = mp_mul_d(&w2, 3, &w2)) != MP_OKAY) {
+ goto ERR;
+ }
+ if ((res = mp_sub(&w2, &w1, &w2)) != MP_OKAY) {
+ goto ERR;
+ }
+ if ((res = mp_sub(&w2, &w3, &w2)) != MP_OKAY) {
+ goto ERR;
+ }
+ /* r1 - r2 */
+ if ((res = mp_sub(&w1, &w2, &w1)) != MP_OKAY) {
+ goto ERR;
+ }
+ /* r3 - r2 */
+ if ((res = mp_sub(&w3, &w2, &w3)) != MP_OKAY) {
+ goto ERR;
+ }
+ /* r1/3 */
+ if ((res = mp_div_3(&w1, &w1, NULL)) != MP_OKAY) {
+ goto ERR;
+ }
+ /* r3/3 */
+ if ((res = mp_div_3(&w3, &w3, NULL)) != MP_OKAY) {
+ goto ERR;
+ }
+
+ /* at this point shift W[n] by B*n */
+ if ((res = mp_lshd(&w1, 1*B)) != MP_OKAY) {
+ goto ERR;
+ }
+ if ((res = mp_lshd(&w2, 2*B)) != MP_OKAY) {
+ goto ERR;
+ }
+ if ((res = mp_lshd(&w3, 3*B)) != MP_OKAY) {
+ goto ERR;
+ }
+ if ((res = mp_lshd(&w4, 4*B)) != MP_OKAY) {
+ goto ERR;
+ }
+
+ if ((res = mp_add(&w0, &w1, b)) != MP_OKAY) {
+ goto ERR;
+ }
+ if ((res = mp_add(&w2, &w3, &tmp1)) != MP_OKAY) {
+ goto ERR;
+ }
+ if ((res = mp_add(&w4, &tmp1, &tmp1)) != MP_OKAY) {
+ goto ERR;
+ }
+ if ((res = mp_add(&tmp1, b, b)) != MP_OKAY) {
+ goto ERR;
+ }
+
+ERR:
+ mp_clear_multi(&w0, &w1, &w2, &w3, &w4, &a0, &a1, &a2, &tmp1, NULL);
+ return res;
+}
+
+#endif