--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libtommath/bn_mp_toom_sqr.c	Sat Feb 03 08:20:34 2007 +0000
@@ -0,0 +1,226 @@
+#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, [email protected], http://math.libtomcrypt.com
+ */
+
+/* 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
+
+/* $Source: /cvs/libtom/libtommath/bn_mp_toom_sqr.c,v $ */
+/* $Revision: 1.3 $ */
+/* $Date: 2006/03/31 14:18:44 $ */