diff --git a/src/runtime/sys_linux_arm.s b/src/runtime/sys_linux_arm.s
index 65935de99f..ca443b699f 100644
--- a/src/runtime/sys_linux_arm.s
+++ b/src/runtime/sys_linux_arm.s
@@ -456,7 +456,7 @@ finish:
 	MOVW	$1000000000, R3
 	MULLU	R0, R3, (R1, R0)
 	ADD.S	R2, R0
-	ADC	R4, R1
+	ADC	$0, R1	// Add carry bit to upper half.
 
 	MOVW	R0, ret_lo+0(FP)
 	MOVW	R1, ret_hi+4(FP)