Moved legacy code into archive, ready for a new rapid(?) prototype.

I may regret doing this!

archive/c/memory/conspage.h

@@ -0,0 +1,68 @@
+/*
+ * conspage.h
+ *
+ * Setup and tear down cons pages, and (FOR NOW) do primitive
+ * allocation/deallocation of cells.
+ * NOTE THAT before we go multi-threaded, these functions must be
+ * aggressively
+ * thread safe.
+ *
+ * (c) 2017 Simon Brooke <simon@journeyman.cc>
+ * Licensed under GPL version 2.0, or, at your option, any later version.
+ */
+#ifndef __psse_conspage_h
+#define __psse_conspage_h
+
+#include "memory/consspaceobject.h"
+
+/**
+ * the number of cons cells on a cons page. The maximum value this can
+ * be (and consequently, the size which, by version 1, it will default
+ * to) is the maximum value of an unsigned 32 bit integer, which is to
+ * say 4294967296. However, we'll start small.
+ */
+#define CONSPAGESIZE 1024
+
+/**
+ * the number of cons pages we will initially allow for. For
+ * convenience we'll set up an array of cons pages this big; however,
+ * later we will want a mechanism for this to be able to grow
+ * dynamically to the maximum we can currently allow, which is
+ * 4294967296.
+ *
+ * Note that this means the total number of addressable cons cells is
+ * 1.8e19, each of 20 bytes; or 3e20 bytes in total; and there are
+ * up to a maximum of 4e9 of heap space objects, each of potentially
+ * 4e9 bytes. So we're talking about a potential total of 8e100 bytes
+ * of addressable memory, which is only slightly more than the
+ * number of atoms in the universe.
+ */
+#define NCONSPAGES 64
+
+/**
+ * a cons page is essentially just an array of cons space objects. It
+ * might later have a local free list (i.e. list of free cells on this
+ * page) and a pointer to the next cons page, but my current view is
+ * that that's probably unneccessary.
+ */
+struct cons_page {
+    struct cons_space_object cell[CONSPAGESIZE];
+};
+
+extern struct cons_pointer privileged_string_memory_exhausted;
+
+extern struct cons_pointer freelist;
+
+extern struct cons_page *conspages[NCONSPAGES];
+
+void free_cell( struct cons_pointer pointer );
+
+struct cons_pointer allocate_cell( uint32_t tag );
+
+void initialise_cons_pages(  );
+
+void dump_pages( URL_FILE * output );
+
+void summarise_allocation(  );
+
+#endif