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From: ado@elsie.UUCP
Newsgroups: net.bugs.4bsd
Subject: asin a la "-lnm" clobbers registers (with fix)
Message-ID: <925@elsie.UUCP>
Date: Mon, 21-May-84 16:45:49 EDT
Article-I.D.: elsie.925
Posted: Mon May 21 16:45:49 1984
Date-Received: Fri, 25-May-84 00:48:09 EDT
Organization: NIH-LEC, Bethesda, MD
Lines: 35

The version of "asin" in the "new math library" clobbers registers 8 and 9.

To see the problem, compile the program below with the "-lnm" option:

	main()
	{
		register	i, j, k, l, m, n;
		extern double	asin();

		i = j = k = l = m = n = 0;
		(void) printf("BEFORE: %2d %2d %13d %13d %2d %2d\n",
			i, j, k, l, m, n);
		(void) asin(0.5);
		(void) printf("AFTER:  %2d %2d %13d %13d %2d %2d\n",
			i, j, k, l, m, n);
	}

The output (on our system) is:
	BEFORE:  0  0             0             0  0  0
	AFTER:   0  0    -333275642   -1197620649  0  0

To fix the problem, redo /usr/lib/libnm.a after replacing the line in
"/usr/src/lib/libnm/asin.s" that reads
		.word	0x0c0
with the following eight lines:
	#
	# Since we may branch to satan,
	# we get to save registers that IT clobbers
	# as well as registers that we clobber.
	# So we change the old
	#	.word	0x0c0
	# to
		.word	0x03c0
--
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