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Arquivotheca.SunOS-4.1.4/usr.lib/libmp/pow.c
seta75D ff309bfe1c Init
2021-10-11 18:37:13 -03:00

67 lines
1.1 KiB
C

/*
* Copyright (c) 1980 Regents of the University of California.
* All rights reserved. The Berkeley software License Agreement
* specifies the terms and conditions for redistribution.
*/
#ifndef lint
static char sccsid[] = "@(#)pow.c 1.1 94/10/31 SMI"; /* from UCB 5.1 4/30/85 */
#endif
/* LINTLIBRARY */
#include <mp.h>
pow(a, b, c, d)
MINT *a, *b, *c, *d;
{
int i, j, n;
MINT x, y;
MINT a0, b0, c0;
a0.len = b0.len = c0.len = x.len = y.len = 0;
_mp_move(a, &a0);
_mp_move(b, &b0);
_mp_move(c, &c0);
xfree(d);
d->len = 1;
d->val = xalloc (1, "pow");
*d->val = 1;
for (j = 0; j < b0.len; j++) {
n = b0.val[b0.len - j - 1];
for (i = 0; i < 15; i++) {
mult(d, d, &x);
mdiv(&x, &c0, &y, d);
if ((n = n << 1) & 0100000) {
mult(&a0, d, &x);
mdiv(&x, &c0, &y, d);
}
}
}
xfree(&x);
xfree(&y);
xfree(&a0);
xfree(&b0);
xfree(&c0);
}
rpow (a, n, b)
MINT *a, *b;
{
MINT x, y;
int i;
x.len = 1;
x.val = xalloc(1, "rpow");
*x.val = n;
y.len = n * a->len + 4;
y.val = xalloc(y.len, "rpow2");
for (i = 0; i < y.len; i++)
y.val[i] = 0;
y.val[y.len - 1] = 010000;
pow(a, &x, &y, b);
xfree(&x);
xfree(&y);
}