mark all block comments that need format preserving so that

[openssl.git] / crypto / bn / bn_sqr.c

diff --git a/crypto/bn/bn_sqr.c b/crypto/bn/bn_sqr.c
index 75f4f38392dcb686f005800652c23de64ea76efd..57da1e46ae5d3bfb5d5bdd592b4aa27a8179760b 100644 (file)
--- a/crypto/bn/bn_sqr.c
+++ b/crypto/bn/bn_sqr.c
@@ -56,39 +56,35 @@
  * [including the GNU Public Licence.]
  */
 
-#include <stdio.h>
 #include "cryptlib.h"
 #include "bn_lcl.h"
 
 /* r must not be a */
 /* I've just gone over this and it is now %20 faster on x86 - eay - 27 Jun 96 */
-int BN_sqr(BIGNUM *r, BIGNUM *a, BN_CTX *ctx)
+int BN_sqr(BIGNUM *r, const BIGNUM *a, BN_CTX *ctx)
        {
        int max,al;
        int ret = 0;
        BIGNUM *tmp,*rr;
 
-#ifdef BN_COUNT
-printf("BN_sqr %d * %d\n",a->top,a->top);
-#endif
        bn_check_top(a);
 
        al=a->top;
        if (al <= 0)
                {
                r->top=0;
-               return(1);
+               r->neg = 0;
+               return 1;
                }
 
        BN_CTX_start(ctx);
        rr=(a != r) ? r : BN_CTX_get(ctx);
        tmp=BN_CTX_get(ctx);
-       if (tmp == NULL) goto err;
+       if (!rr || !tmp) goto err;
 
-       max=(al+al);
-       if (bn_wexpand(rr,max+1) == NULL) goto err;
+       max = 2 * al; /* Non-zero (from above) */
+       if (bn_wexpand(rr,max) == NULL) goto err;
 
-       r->neg=0;
        if (al == 4)
                {
 #ifndef BN_SQR_COMBA
@@ -124,7 +120,6 @@ printf("BN_sqr %d * %d\n",a->top,a->top);
                        k=j+j;
                        if (al == j)
                                {
-                               if (bn_wexpand(a,k*2) == NULL) goto err;
                                if (bn_wexpand(tmp,k*2) == NULL) goto err;
                                bn_sqr_recursive(rr->d,a->d,al,tmp->d);
                                }
@@ -140,20 +135,28 @@ printf("BN_sqr %d * %d\n",a->top,a->top);
 #endif
                }
 
-       rr->top=max;
-       if ((max > 0) && (rr->d[max-1] == 0)) rr->top--;
+       rr->neg=0;
+       /* If the most-significant half of the top word of 'a' is zero, then
+        * the square of 'a' will max-1 words. */
+       if(a->d[al - 1] == (a->d[al - 1] & BN_MASK2l))
+               rr->top = max - 1;
+       else
+               rr->top = max;
        if (rr != r) BN_copy(r,rr);
        ret = 1;
  err:
+       bn_check_top(rr);
+       bn_check_top(tmp);
        BN_CTX_end(ctx);
        return(ret);
        }
 
 /* tmp must have 2*n words */
-void bn_sqr_normal(BN_ULONG *r, BN_ULONG *a, int n, BN_ULONG *tmp)
+void bn_sqr_normal(BN_ULONG *r, const BN_ULONG *a, int n, BN_ULONG *tmp)
        {
        int i,j,max;
-       BN_ULONG *ap,*rp;
+       const BN_ULONG *ap;
+       BN_ULONG *rp;
 
        max=n*2;
        ap=a;
@@ -187,7 +190,8 @@ void bn_sqr_normal(BN_ULONG *r, BN_ULONG *a, int n, BN_ULONG *tmp)
        }
 
 #ifdef BN_RECURSION
-/* r is 2*n words in size,
+/*-
+ * r is 2*n words in size,
  * a and b are both n words in size.    (There's not actually a 'b' here ...)
  * n must be a power of 2.
  * We multiply and return the result.
@@ -197,15 +201,12 @@ void bn_sqr_normal(BN_ULONG *r, BN_ULONG *a, int n, BN_ULONG *tmp)
  * a[0]*b[0]+a[1]*b[1]+(a[0]-a[1])*(b[1]-b[0])
  * a[1]*b[1]
  */
-void bn_sqr_recursive(BN_ULONG *r, BN_ULONG *a, int n2, BN_ULONG *t)
+void bn_sqr_recursive(BN_ULONG *r, const BN_ULONG *a, int n2, BN_ULONG *t)
        {
        int n=n2/2;
        int zero,c1;
        BN_ULONG ln,lo,*p;
 
-#ifdef BN_COUNT
-printf(" bn_sqr_recursive %d * %d\n",n2,n2);
-#endif
        if (n2 == 4)
                {
 #ifndef BN_SQR_COMBA
@@ -245,11 +246,12 @@ printf(" bn_sqr_recursive %d * %d\n",n2,n2);
        if (!zero)
                bn_sqr_recursive(&(t[n2]),t,n,p);
        else
-               memset(&(t[n2]),0,n*sizeof(BN_ULONG));
+               memset(&(t[n2]),0,n2*sizeof(BN_ULONG));
        bn_sqr_recursive(r,a,n,p);
        bn_sqr_recursive(&(r[n2]),&(a[n]),n,p);
 
-       /* t[32] holds (a[0]-a[1])*(a[1]-a[0]), it is negative or zero
+       /*-
+        * t[32] holds (a[0]-a[1])*(a[1]-a[0]), it is negative or zero
         * r[10] holds (a[0]*b[0])
         * r[32] holds (b[1]*b[1])
         */
@@ -259,7 +261,8 @@ printf(" bn_sqr_recursive %d * %d\n",n2,n2);
        /* t[32] is negative */
        c1-=(int)(bn_sub_words(&(t[n2]),t,&(t[n2]),n2));
 
-       /* t[32] holds (a[0]-a[1])*(a[1]-a[0])+(a[0]*a[0])+(a[1]*a[1])
+       /*-
+        * t[32] holds (a[0]-a[1])*(a[1]-a[0])+(a[0]*a[0])+(a[1]*a[1])
         * r[10] holds (a[0]*a[0])
         * r[32] holds (a[1]*a[1])
         * c1 holds the carry bits