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From:   Andreas Schwab <schwab@linux-m68k.org>
To:     linux-m68k@vger.kernel.org
Subject: [PATCH] m68k: fix strcmp inline
CC:     linux-kernel@vger.kernel.org
Date:   Fri, 16 Dec 2022 17:28:39 +0100
Message-ID: <87bko3ia88.fsf@igel.home>
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The return value of strcmp needs to be computed from the ordering of the
unsigned characters.

Signed-off-by: Andreas Schwab <schwab@linux-m68k.org>
---
 arch/m68k/include/asm/string.h | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/arch/m68k/include/asm/string.h b/arch/m68k/include/asm/string.h
index f759d944c449..cdafd67774e0 100644
--- a/arch/m68k/include/asm/string.h
+++ b/arch/m68k/include/asm/string.h
@@ -42,18 +42,19 @@ static inline char *strncpy(char *dest, const char *src, size_t n)
 #define __HAVE_ARCH_STRCMP
 static inline int strcmp(const char *cs, const char *ct)
 {
-	char res;
+	int res = 0, tmp = 0;
 
 	asm ("\n"
 		"1:	move.b	(%0)+,%2\n"	/* get *cs */
-		"	cmp.b	(%1)+,%2\n"	/* compare a byte */
+		"	move.b	(%1)+,%3\n"	/* get *ct */
+		"	cmp.b	%3,%2\n"	/* compare a byte */
 		"	jne	2f\n"		/* not equal, break out */
 		"	tst.b	%2\n"		/* at end of cs? */
 		"	jne	1b\n"		/* no, keep going */
 		"	jra	3f\n"		/* strings are equal */
-		"2:	sub.b	-(%1),%2\n"	/* *cs - *ct */
+		"2:	sub.l	%3,%2\n"	/* *cs - *ct */
 		"3:"
-		: "+a" (cs), "+a" (ct), "=d" (res));
+		: "+a" (cs), "+a" (ct), "+d" (res), "+d" (tmp));
 	return res;
 }
 #endif /* CONFIG_COLDFIRE */
-- 
2.39.0


-- 
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510  2552 DF73 E780 A9DA AEC1
"And now for something completely different."