void NR::mpdiv(Vec_O_UCHR &q, Vec_O_UCHR &r, Vec_I_UCHR &u, Vec_I_UCHR &v)
{
const int MACC=1;
int i,is,mm;
int n=u.size();
int m=v.size();
int p=r.size();
int n_min=MIN(m,p);
if (m > n) nrerror("Divisor longer than dividend in mpdiv");
mm=m+MACC;
Vec_UCHR s(mm),rr(mm),ss(mm+1),qq(n-m+1),t(n);
mpinv(s,v);
mpmul(rr,s,u);
mpsad(ss,rr,1);
mplsh(ss);
mplsh(ss);
mpmov(qq,ss);
mpmov(q,qq);
mpmul(t,qq,v);
mplsh(t);
mpsub(is,t,u,t);
if (is != 0) nrerror("MACC too small in mpdiv");
for (i=0;i<n_min;i++) r[i]=t[i+n-m];
if (p>m)
for (i=m;i<p;i++) r[i]=0;
}
void NR::mpmul(Vec_O_UCHR &w, Vec_I_UCHR &u, Vec_I_UCHR &v)
{
const DP RX=256.0;
int j,n_max,nn=1;
DP cy,t;
int n=u.size();
int m=v.size();
int p=w.size();
n_max=MAX(m,n);
while (nn < n_max) nn <<= 1;
nn <<= 1;
Vec_DP a(0.0,nn),b(0.0,nn);
for (j=0;j<n;j++) a[j]=u[j];
for (j=0;j<m;j++) b[j]=v[j];
realft(a,1);
realft(b,1);
b[0] *= a[0];
b[1] *= a[1];
for (j=2;j<nn;j+=2) {
b[j]=(t=b[j])*a[j]-b[j+1]*a[j+1];
b[j+1]=t*a[j+1]+b[j+1]*a[j];
}
realft(b,-1);
cy=0.0;
for (j=nn-1;j>=0;j--) {
t=b[j]/(nn >> 1)+cy+0.5;
cy=(unsigned long) (t/RX);
b[j]=t-cy*RX;
}
if (cy >= RX) nrerror("cannot happen in mpmul");
for (j=0;j<p;j++) w[j]=0;
w[0]=(unsigned char) cy;
for (j=1;j<MIN(n+m,p);j++)
w[j]=(unsigned char) b[j-1];
}
void NR::mpsqrt(Vec_O_UCHR &w, Vec_O_UCHR &u, Vec_I_UCHR &v)
{
const int MF=3;
const DP BI=1.0/256.0;
int i,ir,j,mm;
DP fu,fv;
int n=u.size();
int m=v.size();
Vec_UCHR r(2*n),x(n+m),s(2*n+m),t(3*n+m);
mm=MIN(m,MF);
fv=DP(v[mm-1]);
for (j=mm-2;j>=0;j--) {
fv *= BI;
fv += v[j];
}
fu=1.0/sqrt(fv);
for (j=0;j<n;j++) {
i=int(fu);
u[j]=(unsigned char) i;
fu=256.0*(fu-i);
}
for (;;) {
mpmul(r,u,u);
mplsh(r);
mpmul(s,r,v);
mplsh(s);
mpneg(s);
s[0] += (unsigned char) 3;
mpsdv(s,s,2,ir);
for (j=1;j<n-1;j++) {
if (s[j] != 0) {
mpmul(t,s,u);
mplsh(t);
mpmov(u,t);
break;
}
}
if (j<n-1) continue;
mpmul(x,u,v);
mplsh(x);
mpmov(w,x);
return;
}
}
