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diff --git a/sys/memio/coerce.x b/sys/memio/coerce.x
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+# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
+
+# COERCE -- Coerce a pointer from one datatype to another, choosing the
+# next larger element for t2 in the event that t1 is not aligned with t2.
+
+pointer procedure coerce (ptr, type1, type2)
+
+pointer	ptr				# input pointer
+int	type1, type2			# from, to data types
+int	n
+pointer	p
+include	<szdtype.inc>
+
+begin
+	p = ptr - 1
+	if (type1 == TY_CHAR)
+	    return (p / ty_size[type2] + 1)
+	else if (type2 == TY_CHAR)
+	    return (p * ty_size[type1] + 1)
+	else {
+	    p = p * ty_size[type1]				# ptr to char
+	    n = ty_size[type2]
+	    return (((p + n-1) / n) + 1)
+	}
+end