/* crypto/bn/bn_word.c */ /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) * All rights reserved. * * This package is an SSL implementation written * by Eric Young (eay@cryptsoft.com). * 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 (tjh@cryptsoft.com). * * 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 (eay@cryptsoft.com)" * 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 (tjh@cryptsoft.com)" * * 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 #include "cryptlib.h" #include "bn_lcl.h" BN_ULONG BN_mod_word(const BIGNUM *a, BN_ULONG w) { #ifndef BN_LLONG BN_ULONG ret=0; #else BN_ULLONG ret=0; #endif int i; w&=BN_MASK2; for (i=a->top-1; i>=0; i--) { #ifndef BN_LLONG ret=((ret<d[i]>>BN_BITS4)&BN_MASK2l))%w; ret=((ret<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); } BN_ULONG BN_div_word(BIGNUM *a, BN_ULONG w) { BN_ULONG ret; int i; if (a->top == 0) return(0); ret=0; 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); } int BN_add_word(BIGNUM *a, BN_ULONG w) { BN_ULONG l; int i; if ((w & BN_MASK2) == 0) return(1); if (a->neg) { a->neg=0; i=BN_sub_word(a,w); if (!BN_is_zero(a)) a->neg=!(a->neg); return(i); } w&=BN_MASK2; if (bn_wexpand(a,a->top+1) == NULL) return(0); i=0; for (;;) { if (i >= a->top) l=w; else 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); } int BN_sub_word(BIGNUM *a, BN_ULONG w) { int i; if ((w & BN_MASK2) == 0) return(1); if (BN_is_zero(a) || a->neg) { a->neg=0; i=BN_add_word(a,w); a->neg=1; return(i); } w&=BN_MASK2; if ((a->top == 1) && (a->d[0] < w)) { a->d[0]=w-a->d[0]; a->neg=1; 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); } int BN_mul_word(BIGNUM *a, BN_ULONG w) { BN_ULONG ll; w&=BN_MASK2; if (a->top) { if (w == 0) BN_zero(a); else { 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); }