TwlIPL/build/libraries_sysmenu/acsign/ARM9/src/bn_word.c

/*---------------------------------------------------------------------------*
  Project:  TwlIPL
  File:     

  Copyright 2007 Nintendo.  All rights reserved.

  These coded instructions, statements, and computer programs contain
  proprietary information of Nintendo of America Inc. and/or Nintendo
  Company Ltd., and are protected by Federal copyright law.  They may
  not be disclosed to third parties or copied or duplicated in any form,
  in whole or in part, without the prior written consent of Nintendo.

  $Date::            $
  $Rev$
  $Author$
 *---------------------------------------------------------------------------*/

/*
 * Copyright (C) 1998-2002 RSA Security Inc. All rights reserved.
 *
 * This work contains proprietary information of RSA Security.
 * Distribution is limited to authorized licensees of RSA
 * Security. Any unauthorized reproduction, distribution or
 * modification of this work is strictly prohibited.
 *
 */

#include "bn_lcl.h"

#if !(defined(NO_SPLIT) && defined(SPLIT_FILE))
 
#ifdef NO_SPLIT
#define SPLIT_BN_MOD_WORD
#define SPLIT_BN_DIV_WORD
#define SPLIT_BN_ADD_WORD
#define SPLIT_BN_SUB_WORD
#define SPLIT_BN_MUL_WORD
#endif /* NO_SPLIT */

#ifdef SPLIT_BN_MOD_WORD
BN_ULONG BN_mod_word(a, w)
BIGNUM *a;
BN_ULONG w;
    {
#ifndef BN_LLONG
    BN_ULONG ret=0;
#else
    BN_ULLONG ret=0;
#endif
    int i;

    w=w&BN_MASK2;//w&=BN_MASK2;
    for (i=a->top-1; i>=0; i--)
        {
#ifndef BN_LLONG
        ret=((ret<<BN_BITS4)|((a->d[i]>>BN_BITS4)&BN_MASK2l))%w;
        ret=((ret<<BN_BITS4)|(a->d[i]&BN_MASK2l))%w;
#else
        ret=(BN_ULLONG)(((ret<<(BN_ULLONG)BN_BITS2)|a->d[i])%
            (BN_ULLONG)w);
#endif
        }
    return((BN_ULONG)ret);
    }
#endif

#ifdef SPLIT_BN_DIV_WORD
BN_ULONG BN_div_word(a, w)
BIGNUM *a;
BN_ULONG w;
    {
    BN_ULONG ret;
    int i;

    if (a->top == 0) return(0);
    ret=0;
    w=w&BN_MASK2;//w&=BN_MASK2;
    for (i=a->top-1; i>=0; i--)
        {
        BN_ULONG l,d;
        
        l=a->d[i];
        d=bn_div_words(ret,l,w);
        ret=(l-((d*w)&BN_MASK2))&BN_MASK2;
        a->d[i]=d;
        }
    if ((a->top > 0) && (a->d[a->top-1] == 0))
        a->top--;
    return(ret);
    }
#endif

#ifdef SPLIT_BN_ADD_WORD
int BN_add_word(a, w)
BIGNUM *a;
BN_ULONG w;
    {
    BN_ULONG l;
    int i;

    if (w == 0) return(1);
    bn_check_top(a);

    w=w&BN_MASK2;//w&=BN_MASK2;
    if (a->neg)
        {
        if(a->top > 1)
            {
            a->neg=0;
            i=BN_sub_word(a,w);
            a->neg=1;
            return(i);
            }
        else
            { /* a->top == 1, it cannot be 0 */
            l=a->d[0];
            if (l > w)
                a->d[0]=l-w;
            else if (l < w)
                {
                a->neg=0;
                a->d[0]=w-l;
                }
            else
                {
                a->neg=0;
                a->top=0;
                }
            return(1);
            }
        }
    w=w&BN_MASK2;//w&=BN_MASK2;
    if (bn_wexpand(a,a->top+1) == NULL) return(0);
    a->d[a->top]=0;
    i=0;
    for (;;)
        {
        l=(a->d[i]+(BN_ULONG)w)&BN_MASK2;
        a->d[i]=l;
        if (w > l)
            w=1;
        else
            break;
        i++;
        }
    if (i >= a->top)
        a->top++;
    return(1);
    }
#endif

#ifdef SPLIT_BN_SUB_WORD
int BN_sub_word(a, w)
BIGNUM *a;
BN_ULONG w;
    {
    int i;

    bn_check_top(a);
    if (w == 0) return(1);

    w=w&BN_MASK2;//w&=BN_MASK2;
    if (a->neg)
        {
        a->neg=0;
        i=BN_add_word(a,w);
        a->neg=1;
        return(i);
        }

    w=w&BN_MASK2;//w&=BN_MASK2;
    if (a->top <= 1)
        {
        BN_ULONG l;

        if (a->top == 0)
            {
            if (bn_wexpand(a,1) == NULL) return(0);
            a->d[0]=w;
            a->neg = 1;
            a->top = 1;
            return(1);
            }
        l=a->d[0];
        if (l == w)
            a->top=0;
        else if (l > w)
            a->d[0]=l-w;
        else
            {
            a->neg=1;
            a->d[0]=w-l;
            }
        return(1);
        }
    i=0;
    for (;;)
        {
        if (a->d[i] >= w)
            {
            a->d[i]-=w;
            break;
            }
        else
            {
            a->d[i]=(a->d[i]-w)&BN_MASK2;
            i++;
            w=1;
            }
        }
    if ((a->d[i] == 0) && (i == (a->top-1)))
        a->top--;
    return(1);
    }
#endif

#ifdef SPLIT_BN_MUL_WORD
int BN_mul_word(a,w)
BIGNUM *a;
BN_ULONG w;
    {
    BN_ULONG ll;

    w=w&BN_MASK2;//w&=BN_MASK2;
    if (a->top)
        {
        ll=bn_mul_words(a->d,a->d,a->top,w);
        if (ll)
            {
            if (bn_wexpand(a,a->top+1) == NULL) return(0);
            a->d[a->top++]=ll;
            }
        }
    return(1);
    }
#endif

#endif