git: 9front

ref: 4999b2f75f14880c0d4e3b44a9e112a1ff861bdd
dir: /sys/src/libmp/port/mpnrand.c/

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#include "os.h"
#include <mp.h>
#include "dat.h"

/* return uniform random [0..n-1] */
mpint*
mpnrand(mpint *n, void (*gen)(uchar*, int), mpint *b)
{
	int bits;

	bits = mpsignif(n);
	if(bits == 0)
		abort();
	if(b == nil){
		b = mpnew(bits);
		setmalloctag(b, getcallerpc(&n));
	}
	do {
		mprand(bits, gen, b);
	} while(mpmagcmp(b, n) >= 0);

	return b;
}