#include "os.h"#include <mp.h>#include "dat.h" // convert an mpint into a big endian byte array (most significant byte first; left adjusted)//   return number of bytes converted//   if p == nil, allocate and result arrayintmptobe(mpint *b, uchar *p, uint n, uchar **pp){	int m; 	m = (mpsignif(b)+7)/8;	if(m == 0)		m++;	if(p == nil){		n = m;		p = malloc(n);		if(p == nil)			sysfatal("mptobe: %r");		setmalloctag(p, getcallerpc(&b));	} else {		if(n < m)			return -1;		if(n > m)			memset(p+m, 0, n-m);	}	if(pp != nil)		*pp = p;	mptober(b, p, m);	return m;}