Path: utzoo!attcan!uunet!iconsys!ohs!stay
From: stay@ohs.UUCP (Steve Taylor)
Newsgroups: comp.sys.mac.programmer
Subject: string initialization in assembly from Think C
Message-ID: <569@ohs.UUCP>
Date: 17 Jul 90 22:02:09 GMT
Organization: Orem High School, Orem, Utah
Lines: 60

I'm using Think C 4.01 on an SE 30.  I was getting an address error
(On a Mac Plus) so I checked out the assembled code in macsbug and
here's what I found:

C Code:

CompareP(p1, p2)
char *p1, *p2;
{
	int 		i, ok = true;
	long		secs;
	DateTimeRec	theDate;
	char		backp[4][16] = {
	"\x39\x0c\x1d\x1a\x05\x00\x00\x37\x00\x0c\x43\x3b\x0a\x01\x09\x0e",
	"\x39\x0c\x1d\x1a\x05\x00\x00\x37\x00\x0c\x43\x3b\x0a\x01\x09\x0e",
	"\x39\x0c\x1d\x1a\x05\x00\x00\x37\x00\x0c\x43\x3b\x0a\x01\x09\x0e",
	"\x39\x0c\x1d\x1a\x05\x00\x00\x37\x00\x0c\x43\x3b\x0a\x01\x09\x0e",
	};

     /* ...Actual function code... */
}

	Compiled by Think C, disassembled by macsbug:

COMPAREP

+0000	LINK	a6, #$FFAA
	MOVEQ	#$01, D0
	MOVE.W	D0, -$004(a6)
	LEA	-$0056(A6), A0
+000E	LEA	-$2D97(A5), A1
	MOVEQ	#$0F, D0
+0014	MOVE.L	(A1)+, (A0)+
	DBF	D0, COMPAREP+0014
	...

Now, since at the time of execution A5 is 0021638E, it's obvious that
the odd address put into A1 on line 000E and accessed (by a long
operation) on line 0014 is the problem.  What I want to know is (1) how
did my my string constants get put at an odd offset from A5),
and (2) if Think C put them there, shouldn't it have known
it couldn't MOVE.L them?  And, (3) how am I supposed to initialize
my array of strings so that this doesn't happen?  (I changed it to
a BlockMove, Thus performing my own initialization, and it worked fine.)
Am I making ridiculous assumptions about what all of this means?

Notes:
	The address error occured on a Mac Plus and SE, but not an SE 30
		or II or IIcx, naturally.
	Go ahead.  Laugh at my initialization technique.
	No, they aren't all the same character sequence.  I got sick
		of typing them.
	Yes, I have "Separate STRS" checked.

Thanks.
-- 
Steven H. Taylor  stay@ohs.uucp  trACE(tm) Development, Alpine School District.
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