New functions BN_CTX_start(), BN_CTX_get(), BN_CTX_end() to access

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

diff --git a/crypto/bn/bn_div.c b/crypto/bn/bn_div.c
index 928773af1c9e1edc1a883b2b880e9f8d7749c4ec..3505221a9667c2f1200ecf61d4aba32c3b83ef62 100644 (file)
--- a/crypto/bn/bn_div.c
+++ b/crypto/bn/bn_div.c
@@ -62,10 +62,12 @@
 #include "bn_lcl.h"
 
 /* The old slow way */
-#if 0
-int BN_div(BIGNUM *dv, BIGNUM *rem, BIGNUM *m, BIGNUM *d, BN_CTX *ctx)
+#if 1
+int BN_div(BIGNUM *dv, BIGNUM *rem, const BIGNUM *m, const BIGNUM *d,
+          BN_CTX *ctx)
        {
        int i,nm,nd;
+       int ret = 0;
        BIGNUM *D;
 
        bn_check_top(m);
@@ -84,14 +86,17 @@ int BN_div(BIGNUM *dv, BIGNUM *rem, BIGNUM *m, BIGNUM *d, BN_CTX *ctx)
                return(1);
                }
 
-       D= &(ctx->bn[ctx->tos]);
-       if (dv == NULL) dv= &(ctx->bn[ctx->tos+1]);
-       if (rem == NULL) rem= &(ctx->bn[ctx->tos+2]);
+       BN_CTX_start(ctx);
+       D = BN_CTX_get(ctx);
+       if (dv == NULL) dv = BN_CTX_get(ctx);
+       if (rem == NULL) rem = BN_CTX_get(ctx);
+       if (D == NULL || dv == NULL || rem == NULL)
+               goto end;
 
        nd=BN_num_bits(d);
        nm=BN_num_bits(m);
-       if (BN_copy(D,d) == NULL) return(0);
-       if (BN_copy(rem,m) == NULL) return(0);
+       if (BN_copy(D,d) == NULL) goto end;
+       if (BN_copy(rem,m) == NULL) goto end;
 
        /* The next 2 are needed so we can do a dv->d[0]|=1 later
         * since BN_lshift1 will only work once there is a value :-) */
@@ -99,21 +104,24 @@ int BN_div(BIGNUM *dv, BIGNUM *rem, BIGNUM *m, BIGNUM *d, BN_CTX *ctx)
        bn_wexpand(dv,1);
        dv->top=1;
 
-       if (!BN_lshift(D,D,nm-nd)) return(0);
+       if (!BN_lshift(D,D,nm-nd)) goto end;
        for (i=nm-nd; i>=0; i--)
                {
-               if (!BN_lshift1(dv,dv)) return(0);
+               if (!BN_lshift1(dv,dv)) goto end;
                if (BN_ucmp(rem,D) >= 0)
                        {
                        dv->d[0]|=1;
-                       if (!BN_usub(rem,rem,D)) return(0);
+                       if (!BN_usub(rem,rem,D)) goto end;
                        }
 /* CAN IMPROVE (and have now :=) */
-               if (!BN_rshift1(D,D)) return(0);
+               if (!BN_rshift1(D,D)) goto end;
                }
        rem->neg=BN_is_zero(rem)?0:m->neg;
        dv->neg=m->neg^d->neg;
-       return(1);
+       ret = 1;
+ end:
+       BN_CTX_end(ctx);
+       return(ret);
        }
 
 #else
@@ -144,13 +152,15 @@ int BN_div(BIGNUM *dv, BIGNUM *rm, const BIGNUM *num, const BIGNUM *divisor,
                return(1);
                }
 
-       tmp= &(ctx->bn[ctx->tos]);
+       BN_CTX_start(ctx);
+       tmp=BN_CTX_get(ctx);
        tmp->neg=0;
-       snum= &(ctx->bn[ctx->tos+1]);
-       sdiv= &(ctx->bn[ctx->tos+2]);
+       snum=BN_CTX_get(ctx);
+       sdiv=BN_CTX_get(ctx);
        if (dv == NULL)
-               res= &(ctx->bn[ctx->tos+3]);
+               res=BN_CTX_get(ctx);
        else    res=dv;
+       if (res == NULL) goto err;
 
        /* First we normalise the numbers */
        norm_shift=BN_BITS2-((BN_num_bits(divisor))%BN_BITS2);
@@ -235,8 +245,13 @@ int BN_div(BIGNUM *dv, BIGNUM *rm, const BIGNUM *num, const BIGNUM *divisor,
                n0=wnump[0];
                n1=wnump[-1];
                if (n0 == d0)
+                       {
                        q=BN_MASK2;
-               else
+#ifdef REMAINDER_IS_ALREADY_CALCULATED /* in this case it isn't */
+                       rem=(n1-q*d0)&BN_MASK2;
+#endif
+                       }
+               else /* n0 < d0 */
 #if defined(BN_LLONG) && defined(BN_DIV2W) && !defined(bn_div_words)
                        q=(BN_ULONG)(((((BN_ULLONG)n0)<<BN_BITS2)|n1)/d0);
 #else
@@ -274,9 +289,14 @@ int BN_div(BIGNUM *dv, BIGNUM *rm, const BIGNUM *num, const BIGNUM *divisor,
                 */
                rem=(n1-q*d0)&BN_MASK2;
 #endif
+#ifdef BN_UMULT_HIGH
+               t2l = d1 * q;
+               t2h = BN_UMULT_HIGH(d1,q);
+#else
                t2l=LBITS(d1); t2h=HBITS(d1);
                ql =LBITS(q);  qh =HBITS(q);
                mul64(t2l,t2h,ql,qh); /* t2=(BN_ULLONG)d1*q; */
+#endif
 
                for (;;)
                        {
@@ -318,8 +338,10 @@ int BN_div(BIGNUM *dv, BIGNUM *rm, const BIGNUM *num, const BIGNUM *divisor,
                BN_rshift(rm,snum,norm_shift);
                rm->neg=num->neg;
                }
+       BN_CTX_end(ctx);
        return(1);
 err:
+       BN_CX_end(ctx);
        return(0);
        }
 
@@ -335,22 +357,27 @@ int BN_mod(BIGNUM *rem, const BIGNUM *m, const BIGNUM *d, BN_CTX *ctx)
        if (BN_ucmp(m,d) < 0)
                return((BN_copy(rem,m) == NULL)?0:1);
 
-       dv= &(ctx->bn[ctx->tos]);
+       BN_CTX_start(ctx);
+       dv=BN_CTX_get(ctx);
 
-       if (!BN_copy(rem,m)) return(0);
+       if (!BN_copy(rem,m)) goto err;
 
        nm=BN_num_bits(rem);
        nd=BN_num_bits(d);
-       if (!BN_lshift(dv,d,nm-nd)) return(0);
+       if (!BN_lshift(dv,d,nm-nd)) goto err;
        for (i=nm-nd; i>=0; i--)
                {
                if (BN_cmp(rem,dv) >= 0)
                        {
-                       if (!BN_sub(rem,rem,dv)) return(0);
+                       if (!BN_sub(rem,rem,dv)) goto err;
                        }
-               if (!BN_rshift1(dv,dv)) return(0);
+               if (!BN_rshift1(dv,dv)) goto err;
                }
+       BN_CTX_end(ctx);
        return(1);
+ err:
+       BN_CTX_end(ctx);
+       return(0);
 #else
        return(BN_div(NULL,rem,m,d,ctx));
 #endif