tomsfastmath/src/generators/comba_sqr_smallgen.c

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2005-07-23 12:43:03 +02:00
/* 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
*/
/* Generates squaring comba code... it learns it knows our secrets! */
#include <stdio.h>
int main(int argc, char **argv)
{
int x, y, z, N, f;
printf(
"void fp_sqr_comba_small(fp_int *A, fp_int *B)\n"
"{\n"
" fp_digit *a, b[32], c0, c1, c2, sc0, sc1, sc2;\n"
);
printf(" switch (A->used) { \n");
for (N = 1; N <= 16; N++) {
printf(
" case %d:\n"
" a = A->dp;\n"
" COMBA_START; \n"
"\n"
" /* clear carries */\n"
" CLEAR_CARRY;\n"
"\n"
" /* output 0 */\n"
" SQRADD(a[0],a[0]);\n"
" COMBA_STORE(b[0]);\n", N);
for (x = 1; x < N+N-1; x++) {
printf(
"\n /* output %d */\n"
" CARRY_FORWARD;\n ", x);
for (f = y = 0; y < N; y++) {
for (z = 0; z < N; z++) {
if (z != y && z + y == x && y <= z) {
++f;
}
}
}
if (f <= 2) {
for (y = 0; y < N; y++) {
for (z = 0; z < N; z++) {
if (y<=z && (y+z)==x) {
if (y == z) {
printf(" SQRADD(a[%d], a[%d]); ", y, y);
} else {
printf(" SQRADD2(a[%d], a[%d]); ", y, z);
}
}
}
}
} else {
// new method
/* do evens first */
f = 0;
for (y = 0; y < N; y++) {
for (z = 0; z < N; z++) {
if (z != y && z + y == x && y <= z) {
if (f == 0) {
// first double
printf("SQRADDSC(a[%d], a[%d]); ", y, z);
f = 1;
} else {
printf("SQRADDAC(a[%d], a[%d]); ", y, z);
}
}
}
}
// forward the carry
printf("SQRADDDB; ");
if ((x&1) == 0) {
// add the square
printf("SQRADD(a[%d], a[%d]); ", x/2, x/2);
}
}
printf("\n COMBA_STORE(b[%d]);\n", x);
}
printf(" COMBA_STORE2(b[%d]);\n", N+N-1);
printf(
" COMBA_FINI;\n"
"\n"
" B->used = %d;\n"
" B->sign = FP_ZPOS;\n"
" memcpy(B->dp, b, %d * sizeof(fp_digit));\n"
" fp_clamp(B);\n"
" break;\n\n", N+N, N+N);
}
printf("}\n\n}\n");
return 0;
}
/* $Source$ */
/* $Revision$ */
/* $Date$ */