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Diffstat (limited to 'lib/libcrypto/bn/bn_div.c')
-rw-r--r--lib/libcrypto/bn/bn_div.c263
1 files changed, 134 insertions, 129 deletions
diff --git a/lib/libcrypto/bn/bn_div.c b/lib/libcrypto/bn/bn_div.c
index e3e06ac054b..04e4a241656 100644
--- a/lib/libcrypto/bn/bn_div.c
+++ b/lib/libcrypto/bn/bn_div.c
@@ -5,21 +5,21 @@
* This package is an SSL implementation written
* by Eric Young (eay@cryptsoft.com).
* The implementation was written so as to conform with Netscapes SSL.
- *
+ *
* This library is free for commercial and non-commercial use as long as
* the following conditions are aheared to. The following conditions
* apply to all code found in this distribution, be it the RC4, RSA,
* lhash, DES, etc., code; not just the SSL code. The SSL documentation
* included with this distribution is covered by the same copyright terms
* except that the holder is Tim Hudson (tjh@cryptsoft.com).
- *
+ *
* Copyright remains Eric Young's, and as such any Copyright notices in
* the code are not to be removed.
* If this package is used in a product, Eric Young should be given attribution
* as the author of the parts of the library used.
* This can be in the form of a textual message at program startup or
* in documentation (online or textual) provided with the package.
- *
+ *
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
@@ -34,10 +34,10 @@
* Eric Young (eay@cryptsoft.com)"
* The word 'cryptographic' can be left out if the rouines from the library
* being used are not cryptographic related :-).
- * 4. If you include any Windows specific code (or a derivative thereof) from
+ * 4. If you include any Windows specific code (or a derivative thereof) from
* the apps directory (application code) you must include an acknowledgement:
* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
- *
+ *
* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
@@ -49,7 +49,7 @@
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
- *
+ *
* The licence and distribution terms for any publically available version or
* derivative of this code cannot be changed. i.e. this code cannot simply be
* copied and put under another distribution licence
@@ -112,132 +112,134 @@
* rm->neg == num->neg (unless the remainder is zero)
* If 'dv' or 'rm' is NULL, the respective value is not returned.
*/
-int BN_div(BIGNUM *dv, BIGNUM *rm, const BIGNUM *num, const BIGNUM *divisor,
- BN_CTX *ctx)
- {
- int norm_shift,i,loop;
- BIGNUM *tmp,wnum,*snum,*sdiv,*res;
- BN_ULONG *resp,*wnump;
- BN_ULONG d0,d1;
- int num_n,div_n;
- int no_branch=0;
+int
+BN_div(BIGNUM *dv, BIGNUM *rm, const BIGNUM *num, const BIGNUM *divisor,
+ BN_CTX *ctx)
+{
+ int norm_shift, i, loop;
+ BIGNUM *tmp, wnum, *snum, *sdiv, *res;
+ BN_ULONG *resp, *wnump;
+ BN_ULONG d0, d1;
+ int num_n, div_n;
+ int no_branch = 0;
/* Invalid zero-padding would have particularly bad consequences
* in the case of 'num', so don't just rely on bn_check_top() for this one
* (bn_check_top() works only for BN_DEBUG builds) */
- if (num->top > 0 && num->d[num->top - 1] == 0)
- {
- BNerr(BN_F_BN_DIV,BN_R_NOT_INITIALIZED);
+ if (num->top > 0 && num->d[num->top - 1] == 0) {
+ BNerr(BN_F_BN_DIV, BN_R_NOT_INITIALIZED);
return 0;
- }
+ }
bn_check_top(num);
- if ((BN_get_flags(num, BN_FLG_CONSTTIME) != 0) || (BN_get_flags(divisor, BN_FLG_CONSTTIME) != 0))
- {
- no_branch=1;
- }
+ if ((BN_get_flags(num, BN_FLG_CONSTTIME) != 0) ||
+ (BN_get_flags(divisor, BN_FLG_CONSTTIME) != 0)) {
+ no_branch = 1;
+ }
bn_check_top(dv);
bn_check_top(rm);
/* bn_check_top(num); */ /* 'num' has been checked already */
bn_check_top(divisor);
- if (BN_is_zero(divisor))
- {
- BNerr(BN_F_BN_DIV,BN_R_DIV_BY_ZERO);
- return(0);
- }
+ if (BN_is_zero(divisor)) {
+ BNerr(BN_F_BN_DIV, BN_R_DIV_BY_ZERO);
+ return (0);
+ }
- if (!no_branch && BN_ucmp(num,divisor) < 0)
- {
- if (rm != NULL)
- { if (BN_copy(rm,num) == NULL) return(0); }
- if (dv != NULL) BN_zero(dv);
- return(1);
+ if (!no_branch && BN_ucmp(num, divisor) < 0) {
+ if (rm != NULL) {
+ if (BN_copy(rm, num) == NULL)
+ return (0);
}
+ if (dv != NULL)
+ BN_zero(dv);
+ return (1);
+ }
BN_CTX_start(ctx);
- tmp=BN_CTX_get(ctx);
- snum=BN_CTX_get(ctx);
- sdiv=BN_CTX_get(ctx);
+ tmp = BN_CTX_get(ctx);
+ snum = BN_CTX_get(ctx);
+ sdiv = BN_CTX_get(ctx);
if (dv == NULL)
- res=BN_CTX_get(ctx);
- else res=dv;
+ res = BN_CTX_get(ctx);
+ else
+ res = dv;
if (sdiv == NULL || res == NULL || tmp == NULL || snum == NULL)
goto err;
/* First we normalise the numbers */
- norm_shift=BN_BITS2-((BN_num_bits(divisor))%BN_BITS2);
- if (!(BN_lshift(sdiv,divisor,norm_shift))) goto err;
- sdiv->neg=0;
- norm_shift+=BN_BITS2;
- if (!(BN_lshift(snum,num,norm_shift))) goto err;
- snum->neg=0;
+ norm_shift = BN_BITS2 - ((BN_num_bits(divisor)) % BN_BITS2);
+ if (!(BN_lshift(sdiv, divisor, norm_shift)))
+ goto err;
+ sdiv->neg = 0;
+ norm_shift += BN_BITS2;
+ if (!(BN_lshift(snum, num, norm_shift)))
+ goto err;
+ snum->neg = 0;
- if (no_branch)
- {
+ if (no_branch) {
/* Since we don't know whether snum is larger than sdiv,
* we pad snum with enough zeroes without changing its
- * value.
+ * value.
*/
- if (snum->top <= sdiv->top+1)
- {
- if (bn_wexpand(snum, sdiv->top + 2) == NULL) goto err;
- for (i = snum->top; i < sdiv->top + 2; i++) snum->d[i] = 0;
+ if (snum->top <= sdiv->top + 1) {
+ if (bn_wexpand(snum, sdiv->top + 2) == NULL)
+ goto err;
+ for (i = snum->top; i < sdiv->top + 2; i++)
+ snum->d[i] = 0;
snum->top = sdiv->top + 2;
- }
- else
- {
- if (bn_wexpand(snum, snum->top + 1) == NULL) goto err;
+ } else {
+ if (bn_wexpand(snum, snum->top + 1) == NULL)
+ goto err;
snum->d[snum->top] = 0;
snum->top ++;
- }
}
+ }
- div_n=sdiv->top;
- num_n=snum->top;
- loop=num_n-div_n;
+ div_n = sdiv->top;
+ num_n = snum->top;
+ loop = num_n - div_n;
/* Lets setup a 'window' into snum
* This is the part that corresponds to the current
* 'area' being divided */
- wnum.neg = 0;
- wnum.d = &(snum->d[loop]);
- wnum.top = div_n;
+ wnum.neg = 0;
+ wnum.d = &(snum->d[loop]);
+ wnum.top = div_n;
/* only needed when BN_ucmp messes up the values between top and max */
wnum.dmax = snum->dmax - loop; /* so we don't step out of bounds */
/* Get the top 2 words of sdiv */
/* div_n=sdiv->top; */
- d0=sdiv->d[div_n-1];
- d1=(div_n == 1)?0:sdiv->d[div_n-2];
+ d0 = sdiv->d[div_n - 1];
+ d1 = (div_n == 1) ? 0 : sdiv->d[div_n - 2];
/* pointer to the 'top' of snum */
- wnump= &(snum->d[num_n-1]);
+ wnump = &(snum->d[num_n - 1]);
/* Setup to 'res' */
- res->neg= (num->neg^divisor->neg);
- if (!bn_wexpand(res,(loop+1))) goto err;
- res->top=loop-no_branch;
- resp= &(res->d[loop-1]);
+ res->neg = (num->neg ^ divisor->neg);
+ if (!bn_wexpand(res, (loop + 1)))
+ goto err;
+ res->top = loop - no_branch;
+ resp = &(res->d[loop - 1]);
/* space for temp */
- if (!bn_wexpand(tmp,(div_n+1))) goto err;
+ if (!bn_wexpand(tmp, (div_n + 1)))
+ goto err;
- if (!no_branch)
- {
- if (BN_ucmp(&wnum,sdiv) >= 0)
- {
+ if (!no_branch) {
+ if (BN_ucmp(&wnum, sdiv) >= 0) {
/* If BN_DEBUG_RAND is defined BN_ucmp changes (via
* bn_pollute) the const bignum arguments =>
* clean the values between top and max again */
bn_clear_top2max(&wnum);
bn_sub_words(wnum.d, wnum.d, sdiv->d, div_n);
- *resp=1;
- }
- else
+ *resp = 1;
+ } else
res->top--;
- }
+ }
/* if res->top == 0 then clear the neg value otherwise decrease
* the resp pointer */
@@ -246,31 +248,30 @@ int BN_div(BIGNUM *dv, BIGNUM *rm, const BIGNUM *num, const BIGNUM *divisor,
else
resp--;
- for (i=0; i<loop-1; i++, wnump--, resp--)
- {
- BN_ULONG q,l0;
+ for (i = 0; i < loop - 1; i++, wnump--, resp--) {
+ BN_ULONG q, l0;
/* the first part of the loop uses the top two words of
* snum and sdiv to calculate a BN_ULONG q such that
* | wnum - sdiv * q | < sdiv */
#if defined(BN_DIV3W) && !defined(OPENSSL_NO_ASM)
- BN_ULONG bn_div_3_words(BN_ULONG*,BN_ULONG,BN_ULONG);
- q=bn_div_3_words(wnump,d1,d0);
+ BN_ULONG bn_div_3_words(BN_ULONG*, BN_ULONG, BN_ULONG);
+ q = bn_div_3_words(wnump, d1, d0);
#else
- BN_ULONG n0,n1,rem=0;
+ BN_ULONG n0, n1, rem = 0;
- n0=wnump[0];
- n1=wnump[-1];
+ n0 = wnump[0];
+ n1 = wnump[-1];
if (n0 == d0)
- q=BN_MASK2;
+ q = BN_MASK2;
else /* n0 < d0 */
- {
+ {
#ifdef BN_LLONG
BN_ULLONG t2;
#if defined(BN_DIV2W) && !defined(bn_div_words)
- q=(BN_ULONG)(((((BN_ULLONG)n0)<<BN_BITS2)|n1)/d0);
+ q = (BN_ULONG)(((((BN_ULLONG)n0) << BN_BITS2)|n1)/d0);
#else
- q=bn_div_words(n0,n1,d0);
+ q = bn_div_words(n0, n1, d0);
#endif
#ifndef REMAINDER_IS_ALREADY_CALCULATED
@@ -278,62 +279,65 @@ int BN_div(BIGNUM *dv, BIGNUM *rm, const BIGNUM *num, const BIGNUM *divisor,
* rem doesn't have to be BN_ULLONG. The least we
* know it's less that d0, isn't it?
*/
- rem=(n1-q*d0)&BN_MASK2;
+ rem = (n1 - q * d0) & BN_MASK2;
#endif
- t2=(BN_ULLONG)d1*q;
+ t2 = (BN_ULLONG)d1*q;
- for (;;)
- {
- if (t2 <= ((((BN_ULLONG)rem)<<BN_BITS2)|wnump[-2]))
+ for (;;) {
+ if (t2 <= ((((BN_ULLONG)rem) << BN_BITS2) |
+ wnump[-2]))
break;
q--;
rem += d0;
if (rem < d0) break; /* don't let rem overflow */
- t2 -= d1;
- }
+ t2 -= d1;
+ }
#else /* !BN_LLONG */
- BN_ULONG t2l,t2h;
+ BN_ULONG t2l, t2h;
- q=bn_div_words(n0,n1,d0);
+ q = bn_div_words(n0, n1, d0);
#ifndef REMAINDER_IS_ALREADY_CALCULATED
- rem=(n1-q*d0)&BN_MASK2;
+ rem = (n1 - q*d0)&BN_MASK2;
#endif
#if defined(BN_UMULT_LOHI)
- BN_UMULT_LOHI(t2l,t2h,d1,q);
+ BN_UMULT_LOHI(t2l, t2h, d1, q);
#elif defined(BN_UMULT_HIGH)
t2l = d1 * q;
- t2h = BN_UMULT_HIGH(d1,q);
+ t2h = BN_UMULT_HIGH(d1, q);
#else
{
- BN_ULONG ql, qh;
- t2l=LBITS(d1); t2h=HBITS(d1);
- ql =LBITS(q); qh =HBITS(q);
- mul64(t2l,t2h,ql,qh); /* t2=(BN_ULLONG)d1*q; */
+ BN_ULONG ql, qh;
+ t2l = LBITS(d1);
+ t2h = HBITS(d1);
+ ql = LBITS(q);
+ qh = HBITS(q);
+ mul64(t2l, t2h, ql, qh); /* t2=(BN_ULLONG)d1*q; */
}
#endif
- for (;;)
- {
+ for (;;) {
if ((t2h < rem) ||
- ((t2h == rem) && (t2l <= wnump[-2])))
+ ((t2h == rem) && (t2l <= wnump[-2])))
break;
q--;
rem += d0;
- if (rem < d0) break; /* don't let rem overflow */
- if (t2l < d1) t2h--; t2l -= d1;
- }
-#endif /* !BN_LLONG */
+ if (rem < d0)
+ break; /* don't let rem overflow */
+ if (t2l < d1)
+ t2h--;
+ t2l -= d1;
}
+#endif /* !BN_LLONG */
+ }
#endif /* !BN_DIV3W */
- l0=bn_mul_words(tmp->d,sdiv->d,div_n,q);
- tmp->d[div_n]=l0;
+ l0 = bn_mul_words(tmp->d, sdiv->d, div_n, q);
+ tmp->d[div_n] = l0;
wnum.d--;
- /* ingore top values of the bignums just sub the two
+ /* ingore top values of the bignums just sub the two
* BN_ULONG arrays with bn_sub_words */
- if (bn_sub_words(wnum.d, wnum.d, tmp->d, div_n+1))
- {
+ if (bn_sub_words(wnum.d, wnum.d, tmp->d, div_n + 1)) {
/* Note: As we have considered only the leading
* two BN_ULONGs in the calculation of q, sdiv * q
* might be greater than wnum (but then (q-1) * sdiv
@@ -345,27 +349,28 @@ int BN_div(BIGNUM *dv, BIGNUM *rm, const BIGNUM *num, const BIGNUM *divisor,
* that q != 0, but if q == 0 then tmp is
* zero anyway) */
(*wnump)++;
- }
+ }
/* store part of the result */
*resp = q;
- }
+ }
bn_correct_top(snum);
- if (rm != NULL)
- {
+ if (rm != NULL) {
/* Keep a copy of the neg flag in num because if rm==num
* BN_rshift() will overwrite it.
*/
int neg = num->neg;
- BN_rshift(rm,snum,norm_shift);
+ BN_rshift(rm, snum, norm_shift);
if (!BN_is_zero(rm))
rm->neg = neg;
bn_check_top(rm);
- }
- if (no_branch) bn_correct_top(res);
+ }
+ if (no_branch)
+ bn_correct_top(res);
BN_CTX_end(ctx);
- return(1);
+ return (1);
+
err:
bn_check_top(rm);
BN_CTX_end(ctx);
- return(0);
- }
+ return (0);
+}
generated by cgit v1.2.3 (git 2.25.1) at 2025-01-27 17:06:27 +0000