diff --git a/sys/arch/sparc64/sparc64/in4_cksum.c b/sys/arch/sparc64/sparc64/in4_cksum.c
index aa69e9d3746a..31dbb637709d 100644
--- a/sys/arch/sparc64/sparc64/in4_cksum.c
+++ b/sys/arch/sparc64/sparc64/in4_cksum.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: in4_cksum.c,v 1.1 2001/08/10 20:53:11 eeh Exp $ */
+/*	$NetBSD: in4_cksum.c,v 1.2 2002/01/21 18:50:36 eeh Exp $ */
 
 /*
  * Copyright (c) 2001 Eduardo Horvath.
@@ -80,19 +80,38 @@ in4_cksum(m, nxt, off, len)
 		ipov.ih_dst = mtod(m, struct ip *)->ip_dst;
 		w = (u_char *)&ipov;
 		/* assumes sizeof(ipov) == 20 */
+#ifdef __arch64__
 		__asm __volatile(" lduw [%5 + 0], %1; "
 			" lduw [%5 + 4], %2; "
 			" lduw [%5 + 8], %3; add %0, %1, %0; "
 			" lduw [%5 + 12], %1; add %0, %2, %0; "
 			" lduw [%5 + 16], %2; add %0, %3, %0; "
-			" mov -1, %3; "
-			" add %0, %1, %0; "
-			" srl %3, 0, %3; "
-			" add %0, %2, %0; "
+			" mov -1, %3; add %0, %1, %0; "
+			" srl %3, 0, %3; add %0, %2, %0; "
 			" srlx %0, 32, %2; and %0, %3, %1; "
 			" add %0, %2, %0; "
 			: "=r" (sum), "=&r" (tmp1), "=&r" (tmp2), "=&r" (tmp3)
 			: "0" (sum), "r" (w));
+#else
+		/* 
+		 * Can't use upper 32-bits of the registers, so this needs to
+		 * be recoded.  So instead of accumulating the carry in the 
+		 * upper 32-bits of the registers, we use addxcc which cannot
+		 * be grouped with any other instructions.
+		 */
+		__asm __volatile(" lduw [%5 + 0], %1; "
+			" lduw [%5 + 4], %2; "
+			" lduw [%5 + 8], %3; addcc %0, %1, %0; "
+			" lduw [%5 + 12], %1; "
+			" addxcc %0, %2, %0; "
+			" lduw [%5 + 16], %2; "
+			" addxcc %0, %3, %0; "
+			" addxcc %0, %1, %0; "
+			" addxcc %0, %2, %0; "
+			" addxcc %0, 0, %0; "
+			: "=r" (sum), "=&r" (tmp1), "=&r" (tmp2), "=&r" (tmp3)
+			: "0" (sum), "r" (w));
+#endif
 	}
 
 	/* skip unnecessary part */
@@ -102,6 +121,5 @@ in4_cksum(m, nxt, off, len)
 		off -= m->m_len;
 		m = m->m_next;
 	}
-	
 	return (in_cksum_internal(m, len, off, sum));
 }
diff --git a/sys/arch/sparc64/sparc64/in_cksum.S b/sys/arch/sparc64/sparc64/in_cksum.S
index 93e68be7d520..3432eb38ec9b 100644
--- a/sys/arch/sparc64/sparc64/in_cksum.S
+++ b/sys/arch/sparc64/sparc64/in_cksum.S
@@ -1,4 +1,4 @@
-/*	$NetBSD: in_cksum.S,v 1.4 2002/01/16 18:49:22 eeh Exp $ */
+/*	$NetBSD: in_cksum.S,v 1.5 2002/01/21 18:50:37 eeh Exp $ */
 
 /*
  * Copyright (c) 2001 Eduardo Horvath
@@ -54,11 +54,13 @@
  */
 
 #define	IALIGN	.align	32
-	
+
+	IALIGN
 ENTRY(in_cksum)
 	clr	%o3		! sum = 0;
 	clr	%o2
 _ENTRY(_C_LABEL(in_cksum_internal))
+	srl	%o3, 0, %o3	! Make sure this is a 32-bit value going in
 	brz	%o0, Lfinish	! for (; m && len > 0; m->m_next) {
 	 clr	%g1		! swapped = 0;
 	brlez	%o1, Lfinish