From 79ba545c0928035adc2a1e99b807b5497008cc5d Mon Sep 17 00:00:00 2001 From: Andy Polyakov Date: Mon, 17 Oct 2011 17:20:48 +0000 Subject: [PATCH] bn_shift.c: minimize reallocations, which allows BN_FLG_STATIC_DATA to be shifted in specific cases. --- crypto/bn/bn_shift.c | 27 +++++++++++++++------------ 1 file changed, 15 insertions(+), 12 deletions(-) diff --git a/crypto/bn/bn_shift.c b/crypto/bn/bn_shift.c index c4d301afc4..a6fca2c424 100644 --- a/crypto/bn/bn_shift.c +++ b/crypto/bn/bn_shift.c @@ -99,7 +99,7 @@ int BN_lshift1(BIGNUM *r, const BIGNUM *a) int BN_rshift1(BIGNUM *r, const BIGNUM *a) { BN_ULONG *ap,*rp,t,c; - int i; + int i,j; bn_check_top(r); bn_check_top(a); @@ -109,22 +109,25 @@ int BN_rshift1(BIGNUM *r, const BIGNUM *a) BN_zero(r); return(1); } + i = a->top; + ap= a->d; + j = i-(ap[i-1]==1); if (a != r) { - if (bn_wexpand(r,a->top) == NULL) return(0); - r->top=a->top; + if (bn_wexpand(r,j) == NULL) return(0); r->neg=a->neg; } - ap=a->d; rp=r->d; - c=0; - for (i=a->top-1; i>=0; i--) + t=ap[--i]; + c=(t&1)?BN_TBIT:0; + if (t>>=1) rp[i]=t; + while (i>0) { - t=ap[i]; + t=ap[--i]; rp[i]=((t>>1)&BN_MASK2)|c; c=(t&1)?BN_TBIT:0; } - bn_correct_top(r); + r->top=j; bn_check_top(r); return(1); } @@ -182,10 +185,11 @@ int BN_rshift(BIGNUM *r, const BIGNUM *a, int n) BN_zero(r); return(1); } + i = (BN_num_bits(a)-n+(BN_BITS2-1))/BN_BITS2; if (r != a) { r->neg=a->neg; - if (bn_wexpand(r,a->top-nw+1) == NULL) return(0); + if (bn_wexpand(r,i) == NULL) return(0); } else { @@ -196,7 +200,7 @@ int BN_rshift(BIGNUM *r, const BIGNUM *a, int n) f= &(a->d[nw]); t=r->d; j=a->top-nw; - r->top=j; + r->top=i; if (rb == 0) { @@ -212,9 +216,8 @@ int BN_rshift(BIGNUM *r, const BIGNUM *a, int n) l= *(f++); *(t++) =(tmp|(l<>rb)&BN_MASK2; + if ((l = (l>>rb)&BN_MASK2)) *(t) = l; } - bn_correct_top(r); bn_check_top(r); return(1); } -- GitLab