--- /dev/null
+/* TomsFastMath, a fast ISO C bignum library.
+ *
+ * This project is meant to fill in where LibTomMath
+ * falls short. That is speed ;-)
+ *
+ * This project is public domain and free for all purposes.
+ *
+ * Tom St Denis, tomstdenis@gmail.com
+ */
+
+#define TFM_DEFINES
+#include "fp_sqr_comba.c"
+
+/* generic comba squarer */
+void fp_sqr_comba(fp_int *A, fp_int *B)
+{
+ int pa, ix, iz;
+ fp_digit c0, c1, c2;
+ fp_int tmp, *dst;
+#ifdef TFM_ISO
+ fp_word tt;
+#endif
+
+ /* get size of output and trim */
+ pa = A->used + A->used;
+ if (pa >= FP_SIZE) {
+ pa = FP_SIZE-1;
+ }
+
+ /* number of output digits to produce */
+ COMBA_START;
+ CLEAR_CARRY;
+
+ if (A == B) {
+ fp_zero(&tmp);
+ dst = &tmp;
+ } else {
+ fp_zero(B);
+ dst = B;
+ }
+
+ for (ix = 0; ix < pa; ix++) {
+ int tx, ty, iy;
+ fp_digit *tmpy, *tmpx;
+
+ /* get offsets into the two bignums */
+ ty = MIN(A->used-1, ix);
+ tx = ix - ty;
+
+ /* setup temp aliases */
+ tmpx = A->dp + tx;
+ tmpy = A->dp + ty;
+
+ /* this is the number of times the loop will iterrate,
+ while (tx++ < a->used && ty-- >= 0) { ... }
+ */
+ iy = MIN(A->used-tx, ty+1);
+
+ /* now for squaring tx can never equal ty
+ * we halve the distance since they approach
+ * at a rate of 2x and we have to round because
+ * odd cases need to be executed
+ */
+ iy = MIN(iy, (ty-tx+1)>>1);
+
+ /* forward carries */
+ CARRY_FORWARD;
+
+ /* execute loop */
+ for (iz = 0; iz < iy; iz++) {
+ fp_digit _tmpx = *tmpx++;
+ fp_digit _tmpy = *tmpy--;
+ SQRADD2(_tmpx, _tmpy);
+ }
+
+ /* even columns have the square term in them */
+ if ((ix&1) == 0) {
+ fp_digit _a_dp = A->dp[ix>>1];
+ SQRADD(_a_dp, A->dp[ix>>1]);
+ }
+
+ /* store it */
+ COMBA_STORE(dst->dp[ix]);
+ }
+
+ COMBA_FINI;
+
+ /* setup dest */
+ dst->used = pa;
+ fp_clamp (dst);
+ if (dst != B) {
+ fp_copy(dst, B);
+ }
+}
+
+/* $Source$ */
+/* $Revision$ */
+/* $Date$ */