Stack uses only references and equation objects

programs/prog1.asm?inline=false

@@ -0,0 +1,31 @@
+//
+// prog1.asm -- an assembler example with global variables
+//
+
+// global Integer x;
+// global Integer y;
+// x = 2;
+// y = x + 3;
+// x = 7 * y + x;
+// writeInteger(x + -33);
+// writeCharacter('\n');
+
+	pushc	2
+	popg	0
+	pushg	0
+	pushc	3
+	add
+	popg	1
+	pushc	7
+	pushg	1
+	mul
+	pushg	0
+	add
+	popg	0
+	pushg	0
+	pushc	-33
+	add
+	wrint
+	pushc	'\n'
+	wrchr
+	halt