Added an array bound checking procedure

lang/m2/libm2/LIST

@@ -33,6 +33,7 @@ blockmove.c
 stackprio.c
 ChkCards.e
 EM.e
+rcka.e
 rcku.e
 rcki.e
 rckul.e

lang/m2/libm2/rcka.e

@@ -0,0 +1,31 @@
+#
+;
+; (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
+; See the copyright notice in the ACK home directory, in the file "Copyright".
+;
+;
+; Module:	range checks for INTEGER, now for array indexing
+; Author:	Ceriel J.H. Jacobs
+; Version:	$Header$
+;
+#include <em_abs.h>
+
+ mes 2,EM_WSIZE,EM_PSIZE
+ exp $rcka
+ pro $rcka, 0
+
+ lol EM_PSIZE
+ zlt *1		; lower bound always 0
+ lol EM_PSIZE
+ lal 0
+ loi EM_PSIZE
+ adp EM_WSIZE
+ loi EM_WSIZE
+ cmi EM_WSIZE
+ zgt *1
+ ret 0
+1
+ loc EARRAY
+ trp
+ ret 0
+ end 0