diff options
| author | Ulf Möller <ulf@openssl.org> | 2000-02-27 02:05:39 +0000 |
|---|---|---|
| committer | Ulf Möller <ulf@openssl.org> | 2000-02-27 02:05:39 +0000 |
| commit | 688938fbb49731397b3afec65a6beb428c4cb6a7 (patch) | |
| tree | 872389259c99427c6f0b1b88d7450026b6800c5c /crypto/bn/bn_mul.c | |
| parent | 9b95f1df4b575daa8e59722454202fd6dc7027b2 (diff) | |
Bug fix!
Diffstat (limited to 'crypto/bn/bn_mul.c')
| -rw-r--r-- | crypto/bn/bn_mul.c | 54 |
1 files changed, 48 insertions, 6 deletions
diff --git a/crypto/bn/bn_mul.c b/crypto/bn/bn_mul.c index ce7c548150..eb007e19e9 100644 --- a/crypto/bn/bn_mul.c +++ b/crypto/bn/bn_mul.c @@ -221,7 +221,7 @@ void bn_mul_part_recursive(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, int tn, int n, BN_ULONG *t) { int i,j,n2=n*2; - unsigned int c1; + unsigned int c1,c2,neg,zero; BN_ULONG ln,lo,*p; # ifdef BN_COUNT @@ -235,9 +235,43 @@ void bn_mul_part_recursive(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, int tn, } /* r=(a[0]-a[1])*(b[1]-b[0]) */ - bn_sub_words(t, a, &(a[n]),n); /* + */ - bn_sub_words(&(t[n]),b, &(b[n]),n); /* - */ - + c1=bn_cmp_words(a,&(a[n]),n); + c2=bn_cmp_words(&(b[n]),b,n); + zero=neg=0; + switch (c1*3+c2) + { + case -4: + bn_sub_words(t, &(a[n]),a, n); /* - */ + bn_sub_words(&(t[n]),b, &(b[n]),n); /* - */ + break; + case -3: + zero=1; + /* break; */ + case -2: + bn_sub_words(t, &(a[n]),a, n); /* - */ + bn_sub_words(&(t[n]),&(b[n]),b, n); /* + */ + neg=1; + break; + case -1: + case 0: + case 1: + zero=1; + /* break; */ + case 2: + bn_sub_words(t, a, &(a[n]),n); /* + */ + bn_sub_words(&(t[n]),b, &(b[n]),n); /* - */ + neg=1; + break; + case 3: + zero=1; + /* break; */ + case 4: + bn_sub_words(t, a, &(a[n]),n); + bn_sub_words(&(t[n]),&(b[n]),b, n); + break; + } + /* The zero case isn't yet implemented here. The speedup + would probably be negligible. */ # if 0 if (n == 4) { @@ -313,7 +347,16 @@ void bn_mul_part_recursive(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, int tn, */ c1=(int)(bn_add_words(t,r,&(r[n2]),n2)); - c1-=(int)(bn_sub_words(&(t[n2]),t,&(t[n2]),n2)); + + if (neg) /* if t[32] is negative */ + { + c1-=(int)(bn_sub_words(&(t[n2]),t,&(t[n2]),n2)); + } + else + { + /* Might have a carry */ + c1+=(int)(bn_add_words(&(t[n2]),&(t[n2]),t,n2)); + } /* t[32] holds (a[0]-a[1])*(b[1]-b[0])+(a[0]*b[0])+(a[1]*b[1]) * r[10] holds (a[0]*b[0]) @@ -674,7 +717,6 @@ int BN_mul(BIGNUM *r, BIGNUM *a, BIGNUM *b, BN_CTX *ctx) } } #endif /* BN_RECURSION */ - if (bn_wexpand(rr,top) == NULL) goto err; rr->top=top; bn_mul_normal(rr->d,a->d,al,b->d,bl); |