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Code

fixed a bigint issue

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git-svn-id: svn://svn.code.sf.net/p/axtls/code/trunk@149 9a5d90b5-6617-0410-8a86-bb477d3ed2e3
This commit is contained in:
cameronrich 2008-03-05 08:47:05 +00:00
parent bf4238d4e7
commit d02abde904
2 changed files with 9 additions and 5 deletions
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10
crypto/bigint.c
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@ -517,7 +517,7 @@ static bigint *bi_int_divide(BI_CTX *ctx, bigint *biR, comp denom)
r = (r<<COMP_BIT_SIZE) + biR->comps[i]; r = (r<<COMP_BIT_SIZE) + biR->comps[i];
biR->comps[i] = (comp)(r / denom); biR->comps[i] = (comp)(r / denom);
r %= denom; r %= denom;
} while (--i != 0); } while (--i >= 0);
return trim(biR); return trim(biR);
} }
@ -947,6 +947,7 @@ static bigint *regular_square(BI_CTX *ctx, bigint *bi)
for (j = i+1; j < t; j++) for (j = i+1; j < t; j++)
{ {
long_comp xx = (long_comp)x[i]*x[j]; long_comp xx = (long_comp)x[i]*x[j];
long_comp xx2 = 2*xx;
long_comp blob = (long_comp)w[i+j]+carry; long_comp blob = (long_comp)w[i+j]+carry;
if (u) /* previous overflow */ if (u) /* previous overflow */
@ -954,13 +955,16 @@ static bigint *regular_square(BI_CTX *ctx, bigint *bi)
blob += COMP_RADIX; blob += COMP_RADIX;
} }
u = 0; u = 0;
if (xx & COMP_BIG_MSB) /* check for overflow */ tmp = xx2 + blob;
/* check for overflow */
if ((COMP_MAX-xx) < xx || (COMP_MAX-xx2) < blob)
{ {
u = 1; u = 1;
} }
tmp = 2*xx + blob;
w[i+j] = (comp)tmp; w[i+j] = (comp)tmp;
carry = (comp)(tmp >> COMP_BIT_SIZE); carry = (comp)(tmp >> COMP_BIT_SIZE);
} }

4
crypto/bigint_impl.h
View File

@ -44,10 +44,10 @@
/* Architecture specific functions for big ints */ /* Architecture specific functions for big ints */
#ifdef WIN32 #ifdef WIN32
#define COMP_RADIX 4294967296i64 #define COMP_RADIX 4294967296i64
#define COMP_BIG_MSB 0x8000000000000000i64 #define COMP_MAX 0xFFFFFFFFFFFFFFFFi64
#else #else
#define COMP_RADIX 4294967296ULL /**< Max component + 1 */ #define COMP_RADIX 4294967296ULL /**< Max component + 1 */
#define COMP_BIG_MSB 0x8000000000000000ULL /**< (Max dbl comp + 1)/ 2 */ #define COMP_MAX 0xFFFFFFFFFFFFFFFFULL/**< (Max dbl comp -1) */
#endif #endif
#define COMP_BIT_SIZE 32 /**< Number of bits in a component. */ #define COMP_BIT_SIZE 32 /**< Number of bits in a component. */
#define COMP_BYTE_SIZE 4 /**< Number of bytes in a component. */ #define COMP_BYTE_SIZE 4 /**< Number of bytes in a component. */