bn_add.c

RMI的处理器au1200系列所用的BOOTLOAD,包括SD卡启动USB启动硬盘启动网络启动,并初始化硬件的所有参数,支持内核调试.

/* crypto/bn/bn_add.c */
/* Copyright (C) 1995-1998 Eric Young ([e-mail])
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young ([e-mail]).
 * The implementation was written so as to conform with Netscapes SSL.
 * 
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson ([e-mail]).
 * 
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young ([e-mail])"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from 
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson ([e-mail])"
 * 
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * 
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.]
 */

#include <stdio.h>
#include "cryptlib.h"
#include "bn_lcl.h"

#include "workaround.h"

/* r can == a or b */
int BN_add(BIGNUM * r, const BIGNUM * a, const BIGNUM * b)
{
    const BIGNUM *tmp;

    bn_check_top(a);
    bn_check_top(b);

    /*  a +  b      a+b
     *  a + -b      a-b
     * -a +  b      b-a
     * -a + -b      -(a+b)
     */
    if (a->neg ^ b->neg) {
	/* only one is negative */
	if (a->neg) {
	    tmp = a;
	    a = b;
	    b = tmp;
	}

	/* we are now a - b */

	if (BN_ucmp(a, b) < 0) {
	    if (!BN_usub(r, b, a))
		return (0);
	    r->neg = 1;
	} else {
	    if (!BN_usub(r, a, b))
		return (0);
	    r->neg = 0;
	}
	return (1);
    }

    if (a->neg)			/* both are neg */
	r->neg = 1;
    else
	r->neg = 0;

    if (!BN_uadd(r, a, b))
	return (0);
    return (1);
}

/* unsigned add of b to a, r must be large enough */
int BN_uadd(BIGNUM * r, const BIGNUM * a, const BIGNUM * b)
{
    register int i;
    int max, min;
    BN_ULONG *ap, *bp, *rp, carry, t1;
    const BIGNUM *tmp;

    bn_check_top(a);
    bn_check_top(b);

    if (a->top < b->top) {
	tmp = a;
	a = b;
	b = tmp;
    }
    max = a->top;
    min = b->top;

    if (bn_wexpand(r, max + 1) == NULL)
	return (0);

    r->top = max;


    ap = a->d;
    bp = b->d;
    rp = r->d;
    carry = 0;

    carry = bn_add_words(rp, ap, bp, min);
    rp += min;
    ap += min;
    bp += min;
    i = min;

    if (carry) {
	while (i < max) {
	    i++;
	    t1 = *(ap++);
	    if ((*(rp++) = (t1 + 1) & BN_MASK2) >= t1) {
		carry = 0;
		break;
	    }
	}
	if ((i >= max) && carry) {
	    *(rp++) = 1;
	    r->top++;
	}
    }
    if (rp != ap) {
	for (; i < max; i++)
	    *(rp++) = *(ap++);
    }
    /* hss_memcpy(rp,ap,sizeof(*ap)*(max-i)); */
    return (1);
}

/* unsigned subtraction of b from a, a must be larger than b. */
int BN_usub(BIGNUM * r, const BIGNUM * a, const BIGNUM * b)
{
    int max, min;
    register BN_ULONG t1, t2, *ap, *bp, *rp;
    int i, carry;
#if defined(IRIX_CC_BUG) && !defined(LINT)
    int dummy;
#endif

    bn_check_top(a);
    bn_check_top(b);

    if (a->top < b->top) {	/* hmm... should not be happening */
	BNerr(BN_F_BN_USUB, BN_R_ARG2_LT_ARG3);
	return (0);
    }

    max = a->top;
    min = b->top;
    if (bn_wexpand(r, max) == NULL)
	return (0);

    ap = a->d;
    bp = b->d;
    rp = r->d;

#if 1
    carry = 0;
    for (i = 0; i < min; i++) {
	t1 = *(ap++);
	t2 = *(bp++);
	if (carry) {
	    carry = (t1 <= t2);
	    t1 = (t1 - t2 - 1) & BN_MASK2;
	} else {
	    carry = (t1 < t2);
	    t1 = (t1 - t2) & BN_MASK2;
	}
#if defined(IRIX_CC_BUG) && !defined(LINT)
	dummy = t1;
#endif
	*(rp++) = t1 & BN_MASK2;
    }
#else
    carry = bn_sub_words(rp, ap, bp, min);
    ap += min;
    bp += min;
    rp += min;
    i = min;
#endif
    if (carry) {		/* subtracted */
	while (i < max) {
	    i++;
	    t1 = *(ap++);
	    t2 = (t1 - 1) & BN_MASK2;
	    *(rp++) = t2;
	    if (t1 > t2)
		break;
	}
    }
#if 0
    hss_memcpy(rp, ap, sizeof(*rp) * (max - i));
#else
    if (rp != ap) {
	for (;;) {
	    if (i++ >= max)
		break;
	    rp[0] = ap[0];
	    if (i++ >= max)
		break;
	    rp[1] = ap[1];
	    if (i++ >= max)
		break;
	    rp[2] = ap[2];
	    if (i++ >= max)
		break;
	    rp[3] = ap[3];
	    rp += 4;
	    ap += 4;
	}
    }
#endif

    r->top = max;
    bn_fix_top(r);
    return (1);
}

int BN_sub(BIGNUM * r, const BIGNUM * a, const BIGNUM * b)
{
    int max;
    int add = 0, neg = 0;
    const BIGNUM *tmp;

    bn_check_top(a);
    bn_check_top(b);

    /*  a -  b      a-b
     *  a - -b      a+b
     * -a -  b      -(a+b)
     * -a - -b      b-a
     */
    if (a->neg) {
	if (b->neg) {
	    tmp = a;
	    a = b;
	    b = tmp;
	} else {
	    add = 1;
	    neg = 1;
	}
    } else {
	if (b->neg) {
	    add = 1;
	    neg = 0;
	}
    }

    if (add) {
	if (!BN_uadd(r, a, b))
	    return (0);
	r->neg = neg;
	return (1);
    }

    /* We are actually doing a - b :-) */

    max = (a->top > b->top) ? a->top : b->top;
    if (bn_wexpand(r, max) == NULL)
	return (0);
    if (BN_ucmp(a, b) < 0) {
	if (!BN_usub(r, b, a))
	    return (0);
	r->neg = 1;
    } else {
	if (!BN_usub(r, a, b))
	    return (0);
	r->neg = 0;
    }
    return (1);
}