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From: emigh@ncsugn.ncsu.edu (Ted H. Emigh)
Newsgroups: comp.bugs.sys5,comp.lang.c,comp.sys.att
Subject: Possible Bug in fpcc Release 1.0
Message-ID: <471@ncsugn.ncsu.edu>
Date: Mon, 22-Jun-87 16:19:06 EDT
Article-I.D.: ncsugn.471
Posted: Mon Jun 22 16:19:06 1987
Date-Received: Tue, 23-Jun-87 05:24:36 EDT
Reply-To: emigh@ncsugn.UUCP (Ted H. Emigh)
Distribution: world
Organization: Genetics, North Carolina State University, Raleigh, NC
Lines: 64
Xref: mnetor comp.bugs.sys5:132 comp.lang.c:2601 comp.sys.att:599

I am trying to get the following segment of code to compile under
fpcc Release 1.0 (12/2/85 -- as far as I can tell, the current release)
on an AT&T 3B2/400 with SVR3.0.  This code comes from a larger package
and I have pared it down somewhat.  For the comp.lang.c folks -- is this
valid C code?  (The person I got this from assures me that it has compiled
under a variety of compilers, systems, etc.).  Of course, I have sent it
through lint and it "passes", and I have been able to compile it on the
unix-pc (SVR1+) Version 3.5 (we don't have cc on the 3B2).  The error
messages I receive follow the program:
---------------------------Start of program---------------------------------
#include <stdio.h>

main ()
{
	printf("Random number is: %i\n",randbin(10,1,2));
	}

/* FUNCTION randbin: return a random binomial number */
/* N is the number of trials; The probability of success is p = p1/p2 */
int
randbin (N, p1, p2)
register
int 	N;         /* Number of trials */
int 	p1, p2;    /* p = p1/p2 */
{
	double p = (double) p1 / (double) p2;
	int r = 0;                /* number of successes */
	double chk;

	while (N-- > 0)
	{
		chk = rand () / (double) 32767.0;
		if (chk < p)
			r++;
		printf("%i  %g  %g   %i \n",N,p,chk,r);
		}
	return (r);
	}

-------------------------------------End of program-------------------------

Now for the errors:
If I compile it without optimization (fpcc -o test test.c) it compiles
and runs perfectly.  If I compile it with optimization (fpcc -O -o test test.c)
I get the following error message:

Assembler: work.c
	aline 37	: operand type mismatch
		... operand #2 of "mmovwd": "%r7"
	aline 39	: operand type mismatch
		... operand #1 of "mfdivd3": "%r7"

As far as I can tell, it is choking on
	double p = (double) p1 / (double) p2;

Is this a bug in fpcc?  Is there any way around it? I hate to use unoptimized
code as this function can be called often during some calculation intensive
situations.

--Ted--
-- 
Ted H. Emigh, Systems NonAdministrator,Genetics, NCSU, Raleigh, NC
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