bn_lib.c
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- /* crypto/bn/bn_lib.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.]
- */
- #ifndef BN_DEBUG
- # undef NDEBUG /* avoid conflicting definitions */
- # define NDEBUG
- #endif
- #include <assert.h>
- #include <limits.h>
- #include <stdio.h>
- #include "cryptlib.h"
- #include "bn_lcl.h"
- const char *BN_version="Big Number" OPENSSL_VERSION_PTEXT;
- /* This stuff appears to be completely unused, so is deprecated */
- #ifndef OPENSSL_NO_DEPRECATED
- /* For a 32 bit machine
- * 2 - 4 == 128
- * 3 - 8 == 256
- * 4 - 16 == 512
- * 5 - 32 == 1024
- * 6 - 64 == 2048
- * 7 - 128 == 4096
- * 8 - 256 == 8192
- */
- static int bn_limit_bits=0;
- static int bn_limit_num=8; /* (1<<bn_limit_bits) */
- static int bn_limit_bits_low=0;
- static int bn_limit_num_low=8; /* (1<<bn_limit_bits_low) */
- static int bn_limit_bits_high=0;
- static int bn_limit_num_high=8; /* (1<<bn_limit_bits_high) */
- static int bn_limit_bits_mont=0;
- static int bn_limit_num_mont=8; /* (1<<bn_limit_bits_mont) */
- void BN_set_params(int mult, int high, int low, int mont)
- {
- if (mult >= 0)
- {
- if (mult > (int)(sizeof(int)*8)-1)
- mult=sizeof(int)*8-1;
- bn_limit_bits=mult;
- bn_limit_num=1<<mult;
- }
- if (high >= 0)
- {
- if (high > (int)(sizeof(int)*8)-1)
- high=sizeof(int)*8-1;
- bn_limit_bits_high=high;
- bn_limit_num_high=1<<high;
- }
- if (low >= 0)
- {
- if (low > (int)(sizeof(int)*8)-1)
- low=sizeof(int)*8-1;
- bn_limit_bits_low=low;
- bn_limit_num_low=1<<low;
- }
- if (mont >= 0)
- {
- if (mont > (int)(sizeof(int)*8)-1)
- mont=sizeof(int)*8-1;
- bn_limit_bits_mont=mont;
- bn_limit_num_mont=1<<mont;
- }
- }
- int BN_get_params(int which)
- {
- if (which == 0) return(bn_limit_bits);
- else if (which == 1) return(bn_limit_bits_high);
- else if (which == 2) return(bn_limit_bits_low);
- else if (which == 3) return(bn_limit_bits_mont);
- else return(0);
- }
- #endif
- const BIGNUM *BN_value_one(void)
- {
- static BN_ULONG data_one=1L;
- static BIGNUM const_one={&data_one,1,1,0,BN_FLG_STATIC_DATA};
- return(&const_one);
- }
- char *BN_options(void)
- {
- static int init=0;
- static char data[16];
- if (!init)
- {
- init++;
- #ifdef BN_LLONG
- BIO_snprintf(data,sizeof data,"bn(%d,%d)",
- (int)sizeof(BN_ULLONG)*8,(int)sizeof(BN_ULONG)*8);
- #else
- BIO_snprintf(data,sizeof data,"bn(%d,%d)",
- (int)sizeof(BN_ULONG)*8,(int)sizeof(BN_ULONG)*8);
- #endif
- }
- return(data);
- }
- int BN_num_bits_word(BN_ULONG l)
- {
- static const char bits[256]={
- 0,1,2,2,3,3,3,3,4,4,4,4,4,4,4,4,
- 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,
- 6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
- 6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
- 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
- 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
- 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
- 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
- 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
- 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
- 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
- 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
- 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
- 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
- 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
- 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
- };
- #if defined(SIXTY_FOUR_BIT_LONG)
- if (l & 0xffffffff00000000L)
- {
- if (l & 0xffff000000000000L)
- {
- if (l & 0xff00000000000000L)
- {
- return(bits[(int)(l>>56)]+56);
- }
- else return(bits[(int)(l>>48)]+48);
- }
- else
- {
- if (l & 0x0000ff0000000000L)
- {
- return(bits[(int)(l>>40)]+40);
- }
- else return(bits[(int)(l>>32)]+32);
- }
- }
- else
- #else
- #ifdef SIXTY_FOUR_BIT
- if (l & 0xffffffff00000000LL)
- {
- if (l & 0xffff000000000000LL)
- {
- if (l & 0xff00000000000000LL)
- {
- return(bits[(int)(l>>56)]+56);
- }
- else return(bits[(int)(l>>48)]+48);
- }
- else
- {
- if (l & 0x0000ff0000000000LL)
- {
- return(bits[(int)(l>>40)]+40);
- }
- else return(bits[(int)(l>>32)]+32);
- }
- }
- else
- #endif
- #endif
- {
- #if defined(THIRTY_TWO_BIT) || defined(SIXTY_FOUR_BIT) || defined(SIXTY_FOUR_BIT_LONG)
- if (l & 0xffff0000L)
- {
- if (l & 0xff000000L)
- return(bits[(int)(l>>24L)]+24);
- else return(bits[(int)(l>>16L)]+16);
- }
- else
- #endif
- {
- #if defined(SIXTEEN_BIT) || defined(THIRTY_TWO_BIT) || defined(SIXTY_FOUR_BIT) || defined(SIXTY_FOUR_BIT_LONG)
- if (l & 0xff00L)
- return(bits[(int)(l>>8)]+8);
- else
- #endif
- return(bits[(int)(l )] );
- }
- }
- }
- int BN_num_bits(const BIGNUM *a)
- {
- int i = a->top - 1;
- bn_check_top(a);
- if (BN_is_zero(a)) return 0;
- return ((i*BN_BITS2) + BN_num_bits_word(a->d[i]));
- }
- void BN_clear_free(BIGNUM *a)
- {
- int i;
- if (a == NULL) return;
- bn_check_top(a);
- if (a->d != NULL)
- {
- OPENSSL_cleanse(a->d,a->dmax*sizeof(a->d[0]));
- if (!(BN_get_flags(a,BN_FLG_STATIC_DATA)))
- OPENSSL_free(a->d);
- }
- i=BN_get_flags(a,BN_FLG_MALLOCED);
- OPENSSL_cleanse(a,sizeof(BIGNUM));
- if (i)
- OPENSSL_free(a);
- }
- void BN_free(BIGNUM *a)
- {
- if (a == NULL) return;
- bn_check_top(a);
- if ((a->d != NULL) && !(BN_get_flags(a,BN_FLG_STATIC_DATA)))
- OPENSSL_free(a->d);
- if (a->flags & BN_FLG_MALLOCED)
- OPENSSL_free(a);
- else
- {
- #ifndef OPENSSL_NO_DEPRECATED
- a->flags|=BN_FLG_FREE;
- #endif
- a->d = NULL;
- }
- }
- void BN_init(BIGNUM *a)
- {
- memset(a,0,sizeof(BIGNUM));
- bn_check_top(a);
- }
- BIGNUM *BN_new(void)
- {
- BIGNUM *ret;
- if ((ret=(BIGNUM *)OPENSSL_malloc(sizeof(BIGNUM))) == NULL)
- {
- BNerr(BN_F_BN_NEW,ERR_R_MALLOC_FAILURE);
- return(NULL);
- }
- ret->flags=BN_FLG_MALLOCED;
- ret->top=0;
- ret->neg=0;
- ret->dmax=0;
- ret->d=NULL;
- bn_check_top(ret);
- return(ret);
- }
- /* This is used both by bn_expand2() and bn_dup_expand() */
- /* The caller MUST check that words > b->dmax before calling this */
- static BN_ULONG *bn_expand_internal(const BIGNUM *b, int words)
- {
- BN_ULONG *A,*a = NULL;
- const BN_ULONG *B;
- int i;
- bn_check_top(b);
- if (words > (INT_MAX/(4*BN_BITS2)))
- {
- BNerr(BN_F_BN_EXPAND_INTERNAL,BN_R_BIGNUM_TOO_LONG);
- return NULL;
- }
- if (BN_get_flags(b,BN_FLG_STATIC_DATA))
- {
- BNerr(BN_F_BN_EXPAND_INTERNAL,BN_R_EXPAND_ON_STATIC_BIGNUM_DATA);
- return(NULL);
- }
- a=A=(BN_ULONG *)OPENSSL_malloc(sizeof(BN_ULONG)*words);
- if (A == NULL)
- {
- BNerr(BN_F_BN_EXPAND_INTERNAL,ERR_R_MALLOC_FAILURE);
- return(NULL);
- }
- #if 1
- B=b->d;
- /* Check if the previous number needs to be copied */
- if (B != NULL)
- {
- for (i=b->top>>2; i>0; i--,A+=4,B+=4)
- {
- /*
- * The fact that the loop is unrolled
- * 4-wise is a tribute to Intel. It's
- * the one that doesn't have enough
- * registers to accomodate more data.
- * I'd unroll it 8-wise otherwise:-)
- *
- * <appro@fy.chalmers.se>
- */
- BN_ULONG a0,a1,a2,a3;
- a0=B[0]; a1=B[1]; a2=B[2]; a3=B[3];
- A[0]=a0; A[1]=a1; A[2]=a2; A[3]=a3;
- }
- switch (b->top&3)
- {
- case 3: A[2]=B[2];
- case 2: A[1]=B[1];
- case 1: A[0]=B[0];
- case 0: /* workaround for ultrix cc: without 'case 0', the optimizer does
- * the switch table by doing a=top&3; a--; goto jump_table[a];
- * which fails for top== 0 */
- ;
- }
- }
- #else
- memset(A,0,sizeof(BN_ULONG)*words);
- memcpy(A,b->d,sizeof(b->d[0])*b->top);
- #endif
-
- return(a);
- }
- /* This is an internal function that can be used instead of bn_expand2()
- * when there is a need to copy BIGNUMs instead of only expanding the
- * data part, while still expanding them.
- * Especially useful when needing to expand BIGNUMs that are declared
- * 'const' and should therefore not be changed.
- * The reason to use this instead of a BN_dup() followed by a bn_expand2()
- * is memory allocation overhead. A BN_dup() followed by a bn_expand2()
- * will allocate new memory for the BIGNUM data twice, and free it once,
- * while bn_dup_expand() makes sure allocation is made only once.
- */
- #ifndef OPENSSL_NO_DEPRECATED
- BIGNUM *bn_dup_expand(const BIGNUM *b, int words)
- {
- BIGNUM *r = NULL;
- bn_check_top(b);
- /* This function does not work if
- * words <= b->dmax && top < words
- * because BN_dup() does not preserve 'dmax'!
- * (But bn_dup_expand() is not used anywhere yet.)
- */
- if (words > b->dmax)
- {
- BN_ULONG *a = bn_expand_internal(b, words);
- if (a)
- {
- r = BN_new();
- if (r)
- {
- r->top = b->top;
- r->dmax = words;
- r->neg = b->neg;
- r->d = a;
- }
- else
- {
- /* r == NULL, BN_new failure */
- OPENSSL_free(a);
- }
- }
- /* If a == NULL, there was an error in allocation in
- bn_expand_internal(), and NULL should be returned */
- }
- else
- {
- r = BN_dup(b);
- }
- bn_check_top(r);
- return r;
- }
- #endif
- /* This is an internal function that should not be used in applications.
- * It ensures that 'b' has enough room for a 'words' word number
- * and initialises any unused part of b->d with leading zeros.
- * It is mostly used by the various BIGNUM routines. If there is an error,
- * NULL is returned. If not, 'b' is returned. */
- BIGNUM *bn_expand2(BIGNUM *b, int words)
- {
- bn_check_top(b);
- if (words > b->dmax)
- {
- BN_ULONG *a = bn_expand_internal(b, words);
- if(!a) return NULL;
- if(b->d) OPENSSL_free(b->d);
- b->d=a;
- b->dmax=words;
- }
- /* None of this should be necessary because of what b->top means! */
- #if 0
- /* NB: bn_wexpand() calls this only if the BIGNUM really has to grow */
- if (b->top < b->dmax)
- {
- int i;
- BN_ULONG *A = &(b->d[b->top]);
- for (i=(b->dmax - b->top)>>3; i>0; i--,A+=8)
- {
- A[0]=0; A[1]=0; A[2]=0; A[3]=0;
- A[4]=0; A[5]=0; A[6]=0; A[7]=0;
- }
- for (i=(b->dmax - b->top)&7; i>0; i--,A++)
- A[0]=0;
- assert(A == &(b->d[b->dmax]));
- }
- #endif
- bn_check_top(b);
- return b;
- }
- BIGNUM *BN_dup(const BIGNUM *a)
- {
- BIGNUM *t;
- if (a == NULL) return NULL;
- bn_check_top(a);
- t = BN_new();
- if (t == NULL) return NULL;
- if(!BN_copy(t, a))
- {
- BN_free(t);
- return NULL;
- }
- bn_check_top(t);
- return t;
- }
- BIGNUM *BN_copy(BIGNUM *a, const BIGNUM *b)
- {
- int i;
- BN_ULONG *A;
- const BN_ULONG *B;
- bn_check_top(b);
- if (a == b) return(a);
- if (bn_wexpand(a,b->top) == NULL) return(NULL);
- #if 1
- A=a->d;
- B=b->d;
- for (i=b->top>>2; i>0; i--,A+=4,B+=4)
- {
- BN_ULONG a0,a1,a2,a3;
- a0=B[0]; a1=B[1]; a2=B[2]; a3=B[3];
- A[0]=a0; A[1]=a1; A[2]=a2; A[3]=a3;
- }
- switch (b->top&3)
- {
- case 3: A[2]=B[2];
- case 2: A[1]=B[1];
- case 1: A[0]=B[0];
- case 0: ; /* ultrix cc workaround, see comments in bn_expand_internal */
- }
- #else
- memcpy(a->d,b->d,sizeof(b->d[0])*b->top);
- #endif
- a->top=b->top;
- a->neg=b->neg;
- bn_check_top(a);
- return(a);
- }
- void BN_swap(BIGNUM *a, BIGNUM *b)
- {
- int flags_old_a, flags_old_b;
- BN_ULONG *tmp_d;
- int tmp_top, tmp_dmax, tmp_neg;
-
- bn_check_top(a);
- bn_check_top(b);
- flags_old_a = a->flags;
- flags_old_b = b->flags;
- tmp_d = a->d;
- tmp_top = a->top;
- tmp_dmax = a->dmax;
- tmp_neg = a->neg;
-
- a->d = b->d;
- a->top = b->top;
- a->dmax = b->dmax;
- a->neg = b->neg;
-
- b->d = tmp_d;
- b->top = tmp_top;
- b->dmax = tmp_dmax;
- b->neg = tmp_neg;
-
- a->flags = (flags_old_a & BN_FLG_MALLOCED) | (flags_old_b & BN_FLG_STATIC_DATA);
- b->flags = (flags_old_b & BN_FLG_MALLOCED) | (flags_old_a & BN_FLG_STATIC_DATA);
- bn_check_top(a);
- bn_check_top(b);
- }
- void BN_clear(BIGNUM *a)
- {
- bn_check_top(a);
- if (a->d != NULL)
- memset(a->d,0,a->dmax*sizeof(a->d[0]));
- a->top=0;
- a->neg=0;
- }
- BN_ULONG BN_get_word(const BIGNUM *a)
- {
- if (a->top > 1)
- return BN_MASK2;
- else if (a->top == 1)
- return a->d[0];
- /* a->top == 0 */
- return 0;
- }
- int BN_set_word(BIGNUM *a, BN_ULONG w)
- {
- bn_check_top(a);
- if (bn_expand(a,(int)sizeof(BN_ULONG)*8) == NULL) return(0);
- a->neg = 0;
- a->d[0] = w;
- a->top = (w ? 1 : 0);
- bn_check_top(a);
- return(1);
- }
- BIGNUM *BN_bin2bn(const unsigned char *s, int len, BIGNUM *ret)
- {
- unsigned int i,m;
- unsigned int n;
- BN_ULONG l;
- BIGNUM *bn = NULL;
- if (ret == NULL)
- ret = bn = BN_new();
- if (ret == NULL) return(NULL);
- bn_check_top(ret);
- l=0;
- n=len;
- if (n == 0)
- {
- ret->top=0;
- return(ret);
- }
- i=((n-1)/BN_BYTES)+1;
- m=((n-1)%(BN_BYTES));
- if (bn_wexpand(ret, (int)i) == NULL)
- {
- if (bn) BN_free(bn);
- return NULL;
- }
- ret->top=i;
- ret->neg=0;
- while (n--)
- {
- l=(l<<8L)| *(s++);
- if (m-- == 0)
- {
- ret->d[--i]=l;
- l=0;
- m=BN_BYTES-1;
- }
- }
- /* need to call this due to clear byte at top if avoiding
- * having the top bit set (-ve number) */
- bn_correct_top(ret);
- return(ret);
- }
- /* ignore negative */
- int BN_bn2bin(const BIGNUM *a, unsigned char *to)
- {
- int n,i;
- BN_ULONG l;
- bn_check_top(a);
- n=i=BN_num_bytes(a);
- while (i--)
- {
- l=a->d[i/BN_BYTES];
- *(to++)=(unsigned char)(l>>(8*(i%BN_BYTES)))&0xff;
- }
- return(n);
- }
- int BN_ucmp(const BIGNUM *a, const BIGNUM *b)
- {
- int i;
- BN_ULONG t1,t2,*ap,*bp;
- bn_check_top(a);
- bn_check_top(b);
- i=a->top-b->top;
- if (i != 0) return(i);
- ap=a->d;
- bp=b->d;
- for (i=a->top-1; i>=0; i--)
- {
- t1= ap[i];
- t2= bp[i];
- if (t1 != t2)
- return((t1 > t2) ? 1 : -1);
- }
- return(0);
- }
- int BN_cmp(const BIGNUM *a, const BIGNUM *b)
- {
- int i;
- int gt,lt;
- BN_ULONG t1,t2;
- if ((a == NULL) || (b == NULL))
- {
- if (a != NULL)
- return(-1);
- else if (b != NULL)
- return(1);
- else
- return(0);
- }
- bn_check_top(a);
- bn_check_top(b);
- if (a->neg != b->neg)
- {
- if (a->neg)
- return(-1);
- else return(1);
- }
- if (a->neg == 0)
- { gt=1; lt= -1; }
- else { gt= -1; lt=1; }
- if (a->top > b->top) return(gt);
- if (a->top < b->top) return(lt);
- for (i=a->top-1; i>=0; i--)
- {
- t1=a->d[i];
- t2=b->d[i];
- if (t1 > t2) return(gt);
- if (t1 < t2) return(lt);
- }
- return(0);
- }
- int BN_set_bit(BIGNUM *a, int n)
- {
- int i,j,k;
- if (n < 0)
- return 0;
- i=n/BN_BITS2;
- j=n%BN_BITS2;
- if (a->top <= i)
- {
- if (bn_wexpand(a,i+1) == NULL) return(0);
- for(k=a->top; k<i+1; k++)
- a->d[k]=0;
- a->top=i+1;
- }
- a->d[i]|=(((BN_ULONG)1)<<j);
- bn_check_top(a);
- return(1);
- }
- int BN_clear_bit(BIGNUM *a, int n)
- {
- int i,j;
- bn_check_top(a);
- if (n < 0) return 0;
- i=n/BN_BITS2;
- j=n%BN_BITS2;
- if (a->top <= i) return(0);
- a->d[i]&=(~(((BN_ULONG)1)<<j));
- bn_correct_top(a);
- return(1);
- }
- int BN_is_bit_set(const BIGNUM *a, int n)
- {
- int i,j;
- bn_check_top(a);
- if (n < 0) return 0;
- i=n/BN_BITS2;
- j=n%BN_BITS2;
- if (a->top <= i) return 0;
- return((a->d[i]&(((BN_ULONG)1)<<j))?1:0);
- }
- int BN_mask_bits(BIGNUM *a, int n)
- {
- int b,w;
- bn_check_top(a);
- if (n < 0) return 0;
- w=n/BN_BITS2;
- b=n%BN_BITS2;
- if (w >= a->top) return 0;
- if (b == 0)
- a->top=w;
- else
- {
- a->top=w+1;
- a->d[w]&= ~(BN_MASK2<<b);
- }
- bn_correct_top(a);
- return(1);
- }
- void BN_set_negative(BIGNUM *a, int b)
- {
- if (b && !BN_is_zero(a))
- a->neg = 1;
- else
- a->neg = 0;
- }
- int bn_cmp_words(const BN_ULONG *a, const BN_ULONG *b, int n)
- {
- int i;
- BN_ULONG aa,bb;
- aa=a[n-1];
- bb=b[n-1];
- if (aa != bb) return((aa > bb)?1:-1);
- for (i=n-2; i>=0; i--)
- {
- aa=a[i];
- bb=b[i];
- if (aa != bb) return((aa > bb)?1:-1);
- }
- return(0);
- }
- /* Here follows a specialised variants of bn_cmp_words(). It has the
- property of performing the operation on arrays of different sizes.
- The sizes of those arrays is expressed through cl, which is the
- common length ( basicall, min(len(a),len(b)) ), and dl, which is the
- delta between the two lengths, calculated as len(a)-len(b).
- All lengths are the number of BN_ULONGs... */
- int bn_cmp_part_words(const BN_ULONG *a, const BN_ULONG *b,
- int cl, int dl)
- {
- int n,i;
- n = cl-1;
- if (dl < 0)
- {
- for (i=dl; i<0; i++)
- {
- if (b[n-i] != 0)
- return -1; /* a < b */
- }
- }
- if (dl > 0)
- {
- for (i=dl; i>0; i--)
- {
- if (a[n+i] != 0)
- return 1; /* a > b */
- }
- }
- return bn_cmp_words(a,b,cl);
- }