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From: shallit@ascutney.dartmouth.edu
Newsgroups: comp.lang.c
Subject: bug in mp?
Message-ID: <13612@dartvax.Dartmouth.EDU>
Date: 23 May 89 19:14:20 GMT
Sender: news@dartvax.Dartmouth.EDU
Reply-To: shallit@ascutney.dartmouth.edu ()
Organization: Dartmouth College
Lines: 38

I would like to hear from users of mp whether the following represents
a bug or just a misunderstanding as to how mp works.

When I try to compute (-10) - (-20), I get -10 instead of 10.
Here's the code:
------------------------------------------------------------------------------

#include <mp.h>

/* compile with cc test.c -lmp   */

main()
{
	MINT *a, *b, *c, *d, *e, *f;

	a = itom(-10);   
	b = itom(-20);
	c = itom(0);   

	msub(a,b,c);   

	d = itom(10);
	e = itom(20);
	f = itom(0);

	msub(d,e,f);

	printf("c = ");
	mout (c);
	printf("\n f = ");
	mout (f);
}

-------------------------------------------------------------------------

Jeff Shallit
Dartmouth College
shallit@dartmouth.edu