commit 626a594

Describe that one of the non-standard extensions only tells the number of writable pages of expanded memory, which in some circumstances is less than the total number of pages if it is running on an emulator which accesses some of the expanded memory pages from disk due to insufficient RAM to store them.

 1@@ -237,7 +237,11 @@ emulator to the program), ? for parameters that may be input and/or output,
 2 
 3 02 >pages*
 4   Tells number of expanded memory pages. (This is the maximum valid value
 5-  for src_page and dst_page in expanded memory operations.)
 6+  for src_page and dst_page in expanded memory operations.) (If some of the
 7+  pages are read-only, then this is only the number of writable pages. The
 8+  number of writable pages might be less than the tital number of pages on
 9+  systems with insufficient memory but that is able to emulate larger
10+  memory by reading from the program file instead.)
11 
12 03 device_id uuid% >version ?extra%
13   Loads a nonstandard device, or a nonstandard command for an existing