diff options
Diffstat (limited to 'crypto/bn/bn_mont.c')
| -rw-r--r-- | crypto/bn/bn_mont.c | 68 |
1 files changed, 47 insertions, 21 deletions
diff --git a/crypto/bn/bn_mont.c b/crypto/bn/bn_mont.c index 932d10b736..e435df61f8 100644 --- a/crypto/bn/bn_mont.c +++ b/crypto/bn/bn_mont.c @@ -1,5 +1,5 @@ /* crypto/bn/bn_mont.c */ -/* Copyright (C) 1995-1997 Eric Young (eay@cryptsoft.com) +/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) * All rights reserved. * * This package is an SSL implementation written @@ -95,8 +95,8 @@ BN_MONT_CTX *mont; BN_CTX *ctx; { BIGNUM *n,*t1,*r; - BN_ULONG *ap,*np,*rp,k,n0,v,v2; - int al,nl,max,i,x; + BN_ULONG *ap,*np,*rp,n0,v; + int al,nl,max,i,x,ri; int retn=0; t1=ctx->bn[ctx->tos]; @@ -105,50 +105,76 @@ BN_CTX *ctx; if (!BN_copy(r,a)) goto err; n=mont->N; - if (!BN_copy(t1,a)) goto err; - BN_mask_bits(t1,mont->ri); - - a=t1; + ap=a->d; + /* mont->ri is the size of mont->N in bits/words */ + al=ri=mont->ri/BN_BITS2; - al=a->top; nl=n->top; if ((al == 0) || (nl == 0)) { r->top=0; return(1); } max=(nl+al+1); /* allow for overflow (no?) XXX */ - if (bn_expand(r,(max)*BN_BITS2) == NULL) goto err; + if (bn_wexpand(r,max) == NULL) goto err; + if (bn_wexpand(ret,max) == NULL) goto err; r->neg=a->neg^n->neg; - ap=a->d; np=n->d; rp=r->d; - /* clear the top bytes of T */ + /* clear the top words of T */ +#if 1 for (i=r->top; i<max; i++) /* memset? XXX */ r->d[i]=0; -/* memset(&(r->d[r->top]),0,(max-r->top)*sizeof(BN_ULONG)); */ +#else + memset(&(r->d[r->top]),0,(max-r->top)*sizeof(BN_ULONG)); +#endif r->top=max; n0=mont->n0; for (i=0; i<nl; i++) { - /* This is were part words probably goes wrong */ - k=(rp[0]*n0)&BN_MASK2; - v=bn_mul_add_word(rp,np,nl,k); - - for (x=nl; v; x++) +#if 0 + int x1,x2; + + if (i+4 > nl) + { + x2=nl; + x1=0; + } + else { - v2=rp[x]; - v2+=v; - rp[x]=v2; - v=((v2&BN_MASK2) < v)?1:0; /* ever true? XXX */ + x2=i+4; + x1=nl-x2; + } + v=bn_mul_add_words(&(rp[x1]),&(np[x1]),x2,(rp[x1]*n0)&BN_MASK2); +#else + v=bn_mul_add_words(rp,np,nl,(rp[0]*n0)&BN_MASK2); +#endif + + if (((rp[nl]+=v)&BN_MASK2) < v) + { + for (x=(nl+1); (((++rp[x])&BN_MASK2) == 0); x++) + ; } rp++; } while (r->d[r->top-1] == 0) r->top--; + /* mont->ri will be a multiple of the word size */ +#if 0 BN_rshift(ret,r,mont->ri); +#else + ap=r->d; + rp=ret->d; + x=ri; + al=r->top-x; + for (i=0; i<al; i++) + { + rp[i]=ap[i+x]; + } + ret->top=al; +#endif if (BN_ucmp(ret,mont->N) >= 0) { |