void ecurve_init(_MIPD_ big a,big b,big p,int type)
{ /* Initialize the active ecurve *
* Asize indicate size of A *
* Bsize indicate size of B */
int as;
#ifndef MR_GENERIC_MT
miracl *mr_mip=get_mip();
#endif
if (mr_mip->ERNUM) return;
MR_IN(93)
prepare_monty(_MIPP_ p);
mr_mip->Asize=size(a);
if (mr_abs(mr_mip->Asize)==MR_TOOBIG)
{
if (mr_mip->Asize>=0)
{ /* big positive number - check it isn't minus something small */
copy(a,mr_mip->w1);
divide(_MIPP_ mr_mip->w1,p,p);
subtract(_MIPP_ p,mr_mip->w1,mr_mip->w1);
as=size(mr_mip->w1);
if (as<MR_TOOBIG) mr_mip->Asize=-as;
else
{
if (mr_mip->A==NULL) mr_mip->A=mirvar(_MIPP_ 0);
nres(_MIPP_ a,mr_mip->A);
}
}
else
{
if (mr_mip->A==NULL) mr_mip->A=mirvar(_MIPP_ 0);
nres(_MIPP_ a,mr_mip->A);
}
}
mr_mip->Bsize=size(b);
if (mr_abs(mr_mip->Bsize)==MR_TOOBIG)
{
if (mr_mip->B==NULL) mr_mip->B=mirvar(_MIPP_ 0);
nres(_MIPP_ b,mr_mip->B);
}
mr_mip->coord=type;
MR_OUT
return;
}
void sftbit(_MIPD_ big x,int n,big z)
{ /* shift x by n bits */
int m;
mr_small sm;
#ifdef MR_OS_THREADS
miracl *mr_mip=get_mip();
#endif
if (mr_mip->ERNUM) return;
copy(x,z);
if (n==0) return;
MR_IN(47)
m=mr_abs(n);
sm=mr_shiftbits((mr_small)1,m%mr_mip->lg2b);
if (n>0)
{ /* shift left */
#ifndef MR_ALWAYS_BINARY
if (mr_mip->base==mr_mip->base2)
{
#endif
mr_shift(_MIPP_ z,n/mr_mip->lg2b,z);
mr_pmul(_MIPP_ z,sm,z);
#ifndef MR_ALWAYS_BINARY
}
else
{
expb2(_MIPP_ m,mr_mip->w1);
multiply(_MIPP_ z,mr_mip->w1,z);
}
#endif
}
else
{ /* shift right */
#ifndef MR_ALWAYS_BINARY
if (mr_mip->base==mr_mip->base2)
{
#endif
mr_shift(_MIPP_ z,n/mr_mip->lg2b,z);
#ifdef MR_FP_ROUNDING
mr_sdiv(_MIPP_ z,sm,mr_invert(sm),z);
#else
mr_sdiv(_MIPP_ z,sm,z);
#endif
#ifndef MR_ALWAYS_BINARY
}
else
{
expb2(_MIPP_ m,mr_mip->w1);
divide(_MIPP_ z,mr_mip->w1,z);
}
#endif
}
MR_OUT
}
#ifdef MR_OS_THREADS
miracl *mr_mip=get_mip();
#endif
if (mr_mip->ERNUM) return;
MR_IN(32)
zero(w);
if (d==0.0)
{
MR_OUT
return;
}
mr_mip->D=d;
s=sign(mr_mip->D);
mr_mip->D=mr_abs(mr_mip->D);
build(_MIPP_ w,dquot);
insign(s,w);
MR_OUT
}
double fdsize(_MIPD_ flash w)
{ /* express flash number as double. */
int i,s,en,ed;
double n,d,b,BIGGEST;
#ifdef MR_OS_THREADS
miracl *mr_mip=get_mip();
#endif
if (mr_mip->ERNUM || size(w)==0) return (0.0);
int egcd(_MIPD_ big x,big y,big z)
{ /* greatest common divisor z=gcd(x,y) by Euclids *
* method using Lehmers algorithm for big numbers */
int q,r,a,b,c,d,n;
mr_small sr,m,sm;
mr_small u,v,lq,lr;
#ifdef MR_FP
mr_small dres;
#endif
big t;
#ifndef MR_GENERIC_MT
miracl *mr_mip=get_mip();
#endif
if (mr_mip->ERNUM) return 0;
MR_IN(12)
copy(x,mr_mip->w1);
copy(y,mr_mip->w2);
insign(PLUS,mr_mip->w1);
insign(PLUS,mr_mip->w2);
a=b=c=d=0;
while (size(mr_mip->w2)!=0)
{
if (b==0)
{ /* update w1 and w2 */
divide(_MIPP_ mr_mip->w1,mr_mip->w2,mr_mip->w2);
t=mr_mip->w1,mr_mip->w1=mr_mip->w2,mr_mip->w2=t; /* swap(w1,w2) */
}
else
{
premult(_MIPP_ mr_mip->w1,c,z);
premult(_MIPP_ mr_mip->w1,a,mr_mip->w1);
premult(_MIPP_ mr_mip->w2,b,mr_mip->w0);
premult(_MIPP_ mr_mip->w2,d,mr_mip->w2);
add(_MIPP_ mr_mip->w1,mr_mip->w0,mr_mip->w1);
add(_MIPP_ mr_mip->w2,z,mr_mip->w2);
}
if (mr_mip->ERNUM || size(mr_mip->w2)==0) break;
n=(int)mr_mip->w1->len;
if (mr_mip->w2->len==1)
{ /* special case if mr_mip->w2 is now small */
sm=mr_mip->w2->w[0];
#ifdef MR_FP_ROUNDING
sr=mr_sdiv(_MIPP_ mr_mip->w1,sm,mr_invert(sm),mr_mip->w1);
#else
sr=mr_sdiv(_MIPP_ mr_mip->w1,sm,mr_mip->w1);
#endif
if (sr==0)
{
copy(mr_mip->w2,mr_mip->w1);
break;
}
zero(mr_mip->w1);
mr_mip->w1->len=1;
mr_mip->w1->w[0]=sr;
while ((sr=MR_REMAIN(mr_mip->w2->w[0],mr_mip->w1->w[0]))!=0)
mr_mip->w2->w[0]=mr_mip->w1->w[0],mr_mip->w1->w[0]=sr;
break;
}
a=1;
b=0;
c=0;
d=1;
m=mr_mip->w1->w[n-1]+1;
if (mr_mip->base==0)
{
#ifndef MR_NOFULLWIDTH
if (m==0)
{
u=mr_mip->w1->w[n-1];
v=mr_mip->w2->w[n-1];
}
else
{
u=muldvm(mr_mip->w1->w[n-1],mr_mip->w1->w[n-2],m,&sr);
v=muldvm(mr_mip->w2->w[n-1],mr_mip->w2->w[n-2],m,&sr);
}
#endif
}
else
{
u=muldiv(mr_mip->w1->w[n-1],mr_mip->base,mr_mip->w1->w[n-2],m,&sr);
v=muldiv(mr_mip->w2->w[n-1],mr_mip->base,mr_mip->w2->w[n-2],m,&sr);
}
forever
{ /* work only with most significant piece */
if (((v+c)==0) || ((v+d)==0)) break;
lq=MR_DIV((u+a),(v+c));
if (lq!=MR_DIV((u+b),(v+d))) break;
if (lq>=(mr_small)(MR_TOOBIG/mr_abs(d))) break;
q=(int)lq;
r=a-q*c;
a=c;
c=r;
r=b-q*d;
b=d;
d=r;
lr=u-lq*v;
u=v;
v=lr;
}
}
copy(mr_mip->w1,z);
MR_OUT
return (size(mr_mip->w1));
}
static int euclid(_MIPD_ big x,int num)
{ /* outputs next c.f. quotient from gcd(w5,w6) */
mr_small sr,m;
#ifdef MR_FP
mr_small dres;
#endif
mr_small lr,lq;
big t;
#ifndef MR_GENERIC_MT
miracl *mr_mip=get_mip();
#endif
if (num==0)
{
mr_mip->oldn=(-1);
mr_mip->carryon=FALSE;
mr_mip->last=FALSE;
if (compare(mr_mip->w6,mr_mip->w5)>0)
{ /* ensure w5>w6 */
t=mr_mip->w5,mr_mip->w5=mr_mip->w6,mr_mip->w6=t;
return (mr_mip->q=0);
}
}
else if (num==mr_mip->oldn || mr_mip->q<0) return mr_mip->q;
mr_mip->oldn=num;
if (mr_mip->carryon) goto middle;
start:
if (size(mr_mip->w6)==0) return (mr_mip->q=(-1));
mr_mip->ndig=(int)mr_mip->w5->len;
mr_mip->carryon=TRUE;
mr_mip->a=1;
mr_mip->b=0;
mr_mip->c=0;
mr_mip->d=1;
if (mr_mip->ndig==1)
{
mr_mip->last=TRUE;
mr_mip->u=mr_mip->w5->w[0];
mr_mip->v=mr_mip->w6->w[0];
}
else
{
m=mr_mip->w5->w[mr_mip->ndig-1]+1;
if (mr_mip->base==0)
{
#ifndef MR_NOFULLWIDTH
if (m==0)
{
mr_mip->u=mr_mip->w5->w[mr_mip->ndig-1];
mr_mip->v=mr_mip->w6->w[mr_mip->ndig-1];
}
else
{
mr_mip->u=muldvm(mr_mip->w5->w[mr_mip->ndig-1],mr_mip->w5->w[mr_mip->ndig-2],m,&sr);
mr_mip->v=muldvm(mr_mip->w6->w[mr_mip->ndig-1],mr_mip->w6->w[mr_mip->ndig-2],m,&sr);
}
#endif
}
else
{
mr_mip->u=muldiv(mr_mip->w5->w[mr_mip->ndig-1],mr_mip->base,mr_mip->w5->w[mr_mip->ndig-2],m,&sr);
mr_mip->v=muldiv(mr_mip->w6->w[mr_mip->ndig-1],mr_mip->base,mr_mip->w6->w[mr_mip->ndig-2],m,&sr);
}
}
mr_mip->ku=mr_mip->u;
mr_mip->kv=mr_mip->v;
middle:
forever
{ /* work only with most significant piece */
if (mr_mip->last)
{
if (mr_mip->v==0) return (mr_mip->q=(-1));
lq=MR_DIV(mr_mip->u,mr_mip->v);
}
else
{
if (((mr_mip->v+mr_mip->c)==0) || ((mr_mip->v+mr_mip->d)==0)) break;
lq=MR_DIV((mr_mip->u+mr_mip->a),(mr_mip->v+mr_mip->c));
if (lq!=MR_DIV((mr_mip->u+mr_mip->b),(mr_mip->v+mr_mip->d))) break;
}
if (lq>=(mr_small)(MR_TOOBIG/mr_abs(mr_mip->d))) break;
mr_mip->q=(int)lq;
mr_mip->r=mr_mip->a-mr_mip->q*mr_mip->c;
mr_mip->a=mr_mip->c;
mr_mip->c=mr_mip->r;
mr_mip->r=mr_mip->b-mr_mip->q*mr_mip->d;
mr_mip->b=mr_mip->d;
mr_mip->d=mr_mip->r;
lr=mr_mip->u-lq*mr_mip->v;
mr_mip->u=mr_mip->v;
mr_mip->v=lr;
return mr_mip->q;
}
mr_mip->carryon=FALSE;
if (mr_mip->b==0)
{ /* update w5 and w6 */
mr_mip->check=OFF;
divide(_MIPP_ mr_mip->w5,mr_mip->w6,mr_mip->w7);
mr_mip->check=ON;
if (mr_lent(mr_mip->w7)>mr_mip->nib) return (mr_mip->q=(-2));
t=mr_mip->w5,mr_mip->w5=mr_mip->w6,mr_mip->w6=t; /* swap(w5,w6) */
copy(mr_mip->w7,x);
return (mr_mip->q=size(x));
}
else
{
mr_mip->check=OFF;
premult(_MIPP_ mr_mip->w5,mr_mip->c,mr_mip->w7);
premult(_MIPP_ mr_mip->w5,mr_mip->a,mr_mip->w5);
premult(_MIPP_ mr_mip->w6,mr_mip->b,mr_mip->w0);
premult(_MIPP_ mr_mip->w6,mr_mip->d,mr_mip->w6);
add(_MIPP_ mr_mip->w5,mr_mip->w0,mr_mip->w5);
add(_MIPP_ mr_mip->w6,mr_mip->w7,mr_mip->w6);
mr_mip->check=ON;
}
goto start;
}
void build(_MIPD_ flash x,int (*gen)(_MIPT_ big,int))
{ /* Build x from its regular c.f. *
* generated by gen() */
mr_small ex1,ex2,ex,st,sr;
int a,b,c,d,rm,q,n,prc,lw2,lw4,lz;
BOOL finoff,last;
big t;
#ifdef MR_OS_THREADS
miracl *mr_mip=get_mip();
#endif
if (mr_mip->ERNUM) return;
MR_IN(48)
zero(mr_mip->w1);
convert(_MIPP_ 1,mr_mip->w2);
convert(_MIPP_ 1,mr_mip->w3);
zero(mr_mip->w4);
finoff=FALSE;
last=FALSE;
n=0;
q=(*gen)(_MIPP_ x,n); /* Note - first quotient may be zero */
ex=mr_mip->base-1;
if (mr_mip->nib==mr_mip->workprec) prc=mr_mip->nib;
else prc=mr_mip->workprec+1;
while (!mr_mip->ERNUM && q>=0)
{
if (q==MR_TOOBIG || n==0 || finoff)
{
if (q!=MR_TOOBIG) convert(_MIPP_ q,x);
else last=FALSE;
mr_mip->check=OFF;
multiply(_MIPP_ mr_mip->w2,x,mr_mip->w0);
subtract(_MIPP_ mr_mip->w1,mr_mip->w0,mr_mip->w7);
mr_mip->check=ON;
if ((int)(mr_mip->w7->len&MR_OBITS)>mr_mip->nib) break;
copy(mr_mip->w7,mr_mip->w1);
t=mr_mip->w1,mr_mip->w1=mr_mip->w2,mr_mip->w2=t; /* swap(w1,w2) */
mr_mip->check=OFF;
multiply(_MIPP_ mr_mip->w4,x,mr_mip->w0);
subtract(_MIPP_ mr_mip->w3,mr_mip->w0,mr_mip->w7);
mr_mip->check=ON;
if ((int)(mr_mip->w7->len&MR_OBITS)>mr_mip->nib)
{ /* oops! */
fpack(_MIPP_ mr_mip->w1,mr_mip->w4,x);
negify(x,x);
mr_mip->EXACT=FALSE;
MR_OUT
return;
}
copy(mr_mip->w7,mr_mip->w3);
t=mr_mip->w3,mr_mip->w3=mr_mip->w4,mr_mip->w4=t; /* swap(w3,w4) */
n++;
}
lw2=(int)(mr_mip->w2->len&MR_OBITS);
lw4=(int)(mr_mip->w4->len&MR_OBITS);
lz=lw2+lw4;
if (lz > prc) break; /* too big - exit */
if (last)
{
if (finoff) break;
finoff=TRUE;
q=(*gen)(_MIPP_ x,n);
continue;
}
if (lz>=prc-1)
{ /* nearly finished - so be careful not to overshoot */
if (mr_mip->base==0)
{
#ifndef MR_NOFULLWIDTH
st=mr_mip->w2->w[lw2-1]+1;
if (st==0) ex1=1;
else ex1=muldvm((mr_small)1,(mr_small)0,st,&sr);
st=mr_mip->w4->w[lw4-1]+1;
if (st==0) ex2=1;
else ex2=muldvm((mr_small)1,(mr_small)0,st,&sr);
#endif
}
else
{
ex1=mr_mip->base/(mr_mip->w2->w[lw2-1]+1);
ex2=mr_mip->base/(mr_mip->w4->w[lw4-1]+1);
}
if (ex2>ex1) ex=ex1,ex1=ex2,ex2=ex;
if (lz==prc) ex=ex2;
else ex=ex1;
last=TRUE;
}
a=1;
b=0;
c=0;
d=1;
forever
{
q=(*gen)(_MIPP_ x,n);
if (q<0 || q>=MR_TOOBIG/mr_abs(d))
{ /* there could be more.... *** V3.21 mod *** */
last=FALSE;
break;
}
rm=b-q*d;
b=d;
d=rm;
rm=a-q*c;
a=c;
c=rm;
n++;
if ((mr_small)(mr_abs(c-d))>ex) break;
}
premult(_MIPP_ mr_mip->w1,c,mr_mip->w7);
premult(_MIPP_ mr_mip->w1,a,mr_mip->w1);
premult(_MIPP_ mr_mip->w2,b,mr_mip->w0);
premult(_MIPP_ mr_mip->w2,d,mr_mip->w2);
add(_MIPP_ mr_mip->w1,mr_mip->w0,mr_mip->w1);
add(_MIPP_ mr_mip->w2,mr_mip->w7,mr_mip->w2);
premult(_MIPP_ mr_mip->w3,c,mr_mip->w7);
premult(_MIPP_ mr_mip->w3,a,mr_mip->w3);
premult(_MIPP_ mr_mip->w4,b,mr_mip->w0);
premult(_MIPP_ mr_mip->w4,d,mr_mip->w4);
add(_MIPP_ mr_mip->w3,mr_mip->w0,mr_mip->w3);
add(_MIPP_ mr_mip->w4,mr_mip->w7,mr_mip->w4);
}
