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openssl/crypto/bn/old/bn_ka.c
Ulf Möller 6b691a5c85 Change functions to ANSI C.
1999-04-19 21:31:43 +00:00

568 lines
11 KiB
C
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#include <stdio.h>
#include <stdlib.h>
#include <strings.h>
#include "bn_lcl.h"
/* r is 2*n2 words in size,
* a and b are both n2 words in size.
* n2 must be a power of 2.
* We multiply and return the result.
* t must be 2*n2 words in size
* We calulate
* a[0]*b[0]
* a[0]*b[0]+a[1]*b[1]+(a[0]-a[1])*(b[1]-b[0])
* a[1]*b[1]
*/
void bn_mul_recursive(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, int n2,
BN_ULONG *t)
{
int n=n2/2;
int neg,zero,c1,c2;
BN_ULONG ln,lo,*p;
#ifdef BN_COUNT
printf(" bn_mul_recursive %d * %d\n",n2,n2);
#endif
if (n2 <= 8)
{
if (n2 == 8)
bn_mul_comba8(r,a,b);
else
bn_mul_normal(r,a,n2,b,n2);
return;
}
if (n2 < BN_MUL_RECURSIVE_SIZE_NORMAL)
{
/* This should not happen */
/*abort(); */
bn_mul_normal(r,a,n2,b,n2);
return;
}
/* r=(a[0]-a[1])*(b[1]-b[0]) */
c1=bn_cmp_words(a,&(a[n]),n);
c2=bn_cmp_words(&(b[n]),b,n);
zero=neg=0;
switch (c1*3+c2)
{
case -4:
bn_sub_words(t, &(a[n]),a, n); /* - */
bn_sub_words(&(t[n]),b, &(b[n]),n); /* - */
break;
case -3:
zero=1;
break;
case -2:
bn_sub_words(t, &(a[n]),a, n); /* - */
bn_sub_words(&(t[n]),&(b[n]),b, n); /* + */
neg=1;
break;
case -1:
case 0:
case 1:
zero=1;
break;
case 2:
bn_sub_words(t, a, &(a[n]),n); /* + */
bn_sub_words(&(t[n]),b, &(b[n]),n); /* - */
neg=1;
break;
case 3:
zero=1;
break;
case 4:
bn_sub_words(t, a, &(a[n]),n);
bn_sub_words(&(t[n]),&(b[n]),b, n);
break;
}
if (n == 8)
{
if (!zero)
bn_mul_comba8(&(t[n2]),t,&(t[n]));
else
memset(&(t[n2]),0,8*sizeof(BN_ULONG));
bn_mul_comba8(r,a,b);
bn_mul_comba8(&(r[n2]),&(a[n]),&(b[n]));
}
else
{
p= &(t[n2*2]);
if (!zero)
bn_mul_recursive(&(t[n2]),t,&(t[n]),n,p);
else
memset(&(t[n2]),0,n*sizeof(BN_ULONG));
bn_mul_recursive(r,a,b,n,p);
bn_mul_recursive(&(r[n2]),&(a[n]),&(b[n]),n,p);
}
/* t[32] holds (a[0]-a[1])*(b[1]-b[0]), c1 is the sign
* r[10] holds (a[0]*b[0])
* r[32] holds (b[1]*b[1])
*/
c1=bn_add_words(t,r,&(r[n2]),n2);
if (neg) /* if t[32] is negative */
{
c1-=bn_sub_words(&(t[n2]),t,&(t[n2]),n2);
}
else
{
/* Might have a carry */
c1+=bn_add_words(&(t[n2]),&(t[n2]),t,n2);
}
/* t[32] holds (a[0]-a[1])*(b[1]-b[0])+(a[0]*b[0])+(a[1]*b[1])
* r[10] holds (a[0]*b[0])
* r[32] holds (b[1]*b[1])
* c1 holds the carry bits
*/
c1+=bn_add_words(&(r[n]),&(r[n]),&(t[n2]),n2);
if (c1)
{
p= &(r[n+n2]);
lo= *p;
ln=(lo+c1)&BN_MASK2;
*p=ln;
/* The overflow will stop before we over write
* words we should not overwrite */
if (ln < c1)
{
do {
p++;
lo= *p;
ln=(lo+1)&BN_MASK2;
*p=ln;
} while (ln == 0);
}
}
}
/* n+tn is the word length
* t needs to be n*4 is size, as does r */
void bn_mul_part_recursive(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, int tn,
int n, BN_ULONG *t)
{
int n2=n*2,i,j;
int c1;
BN_ULONG ln,lo,*p;
#ifdef BN_COUNT
printf(" bn_mul_part_recursive %d * %d\n",tn+n,tn+n);
#endif
if (n < 8)
{
i=tn+n;
bn_mul_normal(r,a,i,b,i);
return;
}
/* r=(a[0]-a[1])*(b[1]-b[0]) */
bn_sub_words(t, a, &(a[n]),n); /* + */
bn_sub_words(&(t[n]),b, &(b[n]),n); /* - */
if (n == 8)
{
bn_mul_comba8(&(t[n2]),t,&(t[n]));
bn_mul_comba8(r,a,b);
bn_mul_normal(&(r[n2]),&(a[n]),tn,&(b[n]),tn);
memset(&(r[n2+tn*2]),0,sizeof(BN_ULONG)*(n2-tn*2));
}
else
{
p= &(t[n2*2]);
bn_mul_recursive(&(t[n2]),t,&(t[n]),n,p);
bn_mul_recursive(r,a,b,n,p);
i=n/2;
/* If there is only a bottom half to the number,
* just do it */
j=tn-i;
if (j == 0)
{
bn_mul_recursive(&(r[n2]),&(a[n]),&(b[n]),i,p);
memset(&(r[n2+i*2]),0,sizeof(BN_ULONG)*(n2-i*2));
}
else if (j > 0) /* eg, n == 16, i == 8 and tn == 11 */
{
bn_mul_part_recursive(&(r[n2]),&(a[n]),&(b[n]),
j,i,p);
memset(&(r[n2+tn*2]),0,
sizeof(BN_ULONG)*(n2-tn*2));
}
else /* (j < 0) eg, n == 16, i == 8 and tn == 5 */
{
memset(&(r[n2]),0,sizeof(BN_ULONG)*(tn*2));
for (;;)
{
i/=2;
if (i < tn)
{
bn_mul_part_recursive(&(r[n2]),
&(a[n]),&(b[n]),
tn-i,i,p);
break;
}
else if (i == tn)
{
bn_mul_recursive(&(r[n2]),
&(a[n]),&(b[n]),
i,p);
break;
}
}
}
}
/* t[32] holds (a[0]-a[1])*(b[1]-b[0]), c1 is the sign
* r[10] holds (a[0]*b[0])
* r[32] holds (b[1]*b[1])
*/
c1=bn_add_words(t,r,&(r[n2]),n2);
c1-=bn_sub_words(&(t[n2]),t,&(t[n2]),n2);
/* t[32] holds (a[0]-a[1])*(b[1]-b[0])+(a[0]*b[0])+(a[1]*b[1])
* r[10] holds (a[0]*b[0])
* r[32] holds (b[1]*b[1])
* c1 holds the carry bits
*/
c1+=bn_add_words(&(r[n]),&(r[n]),&(t[n2]),n2);
if (c1)
{
p= &(r[n+n2]);
lo= *p;
ln=(lo+c1)&BN_MASK2;
*p=ln;
/* The overflow will stop before we over write
* words we should not overwrite */
if (ln < c1)
{
do {
p++;
lo= *p;
ln=(lo+1)&BN_MASK2;
*p=ln;
} while (ln == 0);
}
}
}
/* r is 2*n words in size,
* a and b are both n words in size.
* n must be a power of 2.
* We multiply and return the result.
* t must be 2*n words in size
* We calulate
* a[0]*b[0]
* 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)
{
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)
{
bn_sqr_comba4(r,a);
return;
}
else if (n2 == 8)
{
bn_sqr_comba8(r,a);
return;
}
if (n2 < BN_SQR_RECURSIVE_SIZE_NORMAL)
{
bn_sqr_normal(r,a,n2,t);
return;
abort();
}
/* r=(a[0]-a[1])*(a[1]-a[0]) */
c1=bn_cmp_words(a,&(a[n]),n);
zero=0;
if (c1 > 0)
bn_sub_words(t,a,&(a[n]),n);
else if (c1 < 0)
bn_sub_words(t,&(a[n]),a,n);
else
zero=1;
/* The result will always be negative unless it is zero */
if (n == 8)
{
if (!zero)
bn_sqr_comba8(&(t[n2]),t);
else
memset(&(t[n2]),0,8*sizeof(BN_ULONG));
bn_sqr_comba8(r,a);
bn_sqr_comba8(&(r[n2]),&(a[n]));
}
else
{
p= &(t[n2*2]);
if (!zero)
bn_sqr_recursive(&(t[n2]),t,n,p);
else
memset(&(t[n2]),0,n*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
* r[10] holds (a[0]*b[0])
* r[32] holds (b[1]*b[1])
*/
c1=bn_add_words(t,r,&(r[n2]),n2);
/* t[32] is negative */
c1-=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])
* r[10] holds (a[0]*a[0])
* r[32] holds (a[1]*a[1])
* c1 holds the carry bits
*/
c1+=bn_add_words(&(r[n]),&(r[n]),&(t[n2]),n2);
if (c1)
{
p= &(r[n+n2]);
lo= *p;
ln=(lo+c1)&BN_MASK2;
*p=ln;
/* The overflow will stop before we over write
* words we should not overwrite */
if (ln < c1)
{
do {
p++;
lo= *p;
ln=(lo+1)&BN_MASK2;
*p=ln;
} while (ln == 0);
}
}
}
#if 1
/* a and b must be the same size, which is n2.
* r needs to be n2 words and t needs to be n2*2
*/
void bn_mul_low_recursive(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, int n2,
BN_ULONG *t)
{
int n=n2/2;
#ifdef BN_COUNT
printf(" bn_mul_low_recursive %d * %d\n",n2,n2);
#endif
bn_mul_recursive(r,a,b,n,&(t[0]));
if (n > BN_MUL_LOW_RECURSIVE_SIZE_NORMAL)
{
bn_mul_low_recursive(&(t[0]),&(a[0]),&(b[n]),n,&(t[n2]));
bn_add_words(&(r[n]),&(r[n]),&(t[0]),n);
bn_mul_low_recursive(&(t[0]),&(a[n]),&(b[0]),n,&(t[n2]));
bn_add_words(&(r[n]),&(r[n]),&(t[0]),n);
}
else
{
bn_mul_low_normal(&(t[0]),&(a[0]),&(b[n]),n);
bn_mul_low_normal(&(t[n]),&(a[n]),&(b[0]),n);
bn_add_words(&(r[n]),&(r[n]),&(t[0]),n);
bn_add_words(&(r[n]),&(r[n]),&(t[n]),n);
}
}
/* a and b must be the same size, which is n2.
* r needs to be n2 words and t needs to be n2*2
* l is the low words of the output.
* t needs to be n2*3
*/
void bn_mul_high(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, BN_ULONG *l, int n2,
BN_ULONG *t)
{
int j,i,n,c1,c2;
int neg,oneg,zero;
BN_ULONG ll,lc,*lp,*mp;
#ifdef BN_COUNT
printf(" bn_mul_high %d * %d\n",n2,n2);
#endif
n=(n2+1)/2;
/* Calculate (al-ah)*(bh-bl) */
neg=zero=0;
c1=bn_cmp_words(&(a[0]),&(a[n]),n);
c2=bn_cmp_words(&(b[n]),&(b[0]),n);
switch (c1*3+c2)
{
case -4:
bn_sub_words(&(r[0]),&(a[n]),&(a[0]),n);
bn_sub_words(&(r[n]),&(b[0]),&(b[n]),n);
break;
case -3:
zero=1;
break;
case -2:
bn_sub_words(&(r[0]),&(a[n]),&(a[0]),n);
bn_sub_words(&(r[n]),&(b[n]),&(b[0]),n);
neg=1;
break;
case -1:
case 0:
case 1:
zero=1;
break;
case 2:
bn_sub_words(&(r[0]),&(a[0]),&(a[n]),n);
bn_sub_words(&(r[n]),&(b[0]),&(b[n]),n);
neg=1;
break;
case 3:
zero=1;
break;
case 4:
bn_sub_words(&(r[0]),&(a[0]),&(a[n]),n);
bn_sub_words(&(r[n]),&(b[n]),&(b[0]),n);
break;
}
oneg=neg;
/* t[10] = (a[0]-a[1])*(b[1]-b[0]) */
bn_mul_recursive(&(t[0]),&(r[0]),&(r[n]),n,&(t[n2]));
/* r[10] = (a[1]*b[1]) */
bn_mul_recursive(r,&(a[n]),&(b[n]),n,&(t[n2]));
/* s0 == low(al*bl)
* s1 == low(ah*bh)+low((al-ah)*(bh-bl))+low(al*bl)+high(al*bl)
* We know s0 and s1 so the only unknown is high(al*bl)
* high(al*bl) == s1 - low(ah*bh+s0+(al-ah)*(bh-bl))
* high(al*bl) == s1 - (r[0]+l[0]+t[0])
*/
if (l != NULL)
{
lp= &(t[n2+n]);
c1=bn_add_words(lp,&(r[0]),&(l[0]),n);
}
else
{
c1=0;
lp= &(r[0]);
}
if (neg)
neg=bn_sub_words(&(t[n2]),lp,&(t[0]),n);
else
{
bn_add_words(&(t[n2]),lp,&(t[0]),n);
neg=0;
}
if (l != NULL)
{
bn_sub_words(&(t[n2+n]),&(l[n]),&(t[n2]),n);
}
else
{
lp= &(t[n2+n]);
mp= &(t[n2]);
for (i=0; i<n; i++)
lp[i]=((~mp[i])+1)&BN_MASK2;
}
/* s[0] = low(al*bl)
* t[3] = high(al*bl)
* t[10] = (a[0]-a[1])*(b[1]-b[0]) neg is the sign
* r[10] = (a[1]*b[1])
*/
/* R[10] = al*bl
* R[21] = al*bl + ah*bh + (a[0]-a[1])*(b[1]-b[0])
* R[32] = ah*bh
*/
/* R[1]=t[3]+l[0]+r[0](+-)t[0] (have carry/borrow)
* R[2]=r[0]+t[3]+r[1](+-)t[1] (have carry/borrow)
* R[3]=r[1]+(carry/borrow)
*/
if (l != NULL)
{
lp= &(t[n2]);
c1= bn_add_words(lp,&(t[n2+n]),&(l[0]),n);
}
else
{
lp= &(t[n2+n]);
c1=0;
}
c1+=bn_add_words(&(t[n2]),lp, &(r[0]),n);
if (oneg)
c1-=bn_sub_words(&(t[n2]),&(t[n2]),&(t[0]),n);
else
c1+=bn_add_words(&(t[n2]),&(t[n2]),&(t[0]),n);
c2 =bn_add_words(&(r[0]),&(r[0]),&(t[n2+n]),n);
c2+=bn_add_words(&(r[0]),&(r[0]),&(r[n]),n);
if (oneg)
c2-=bn_sub_words(&(r[0]),&(r[0]),&(t[n]),n);
else
c2+=bn_add_words(&(r[0]),&(r[0]),&(t[n]),n);
if (c1 != 0) /* Add starting at r[0], could be +ve or -ve */
{
i=0;
if (c1 > 0)
{
lc=c1;
do {
ll=(r[i]+lc)&BN_MASK2;
r[i++]=ll;
lc=(lc > ll);
} while (lc);
}
else
{
lc= -c1;
do {
ll=r[i];
r[i++]=(ll-lc)&BN_MASK2;
lc=(lc > ll);
} while (lc);
}
}
if (c2 != 0) /* Add starting at r[1] */
{
i=n;
if (c2 > 0)
{
lc=c2;
do {
ll=(r[i]+lc)&BN_MASK2;
r[i++]=ll;
lc=(lc > ll);
} while (lc);
}
else
{
lc= -c2;
do {
ll=r[i];
r[i++]=(ll-lc)&BN_MASK2;
lc=(lc > ll);
} while (lc);
}
}
}
#endif
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