So, I got my old source to build and boot under grub. I now have my old hello world style Ada kernel. I had to remove the "pragma Restrictions(No_Elaboration_Code);" lines from all the source files that I had and also the "pragma Suppress_Initialization" lines I had in there (I honestly can't even remember why I had that in there at all). I included the following in a new gnat.adc file: -- Basic stuff. pragma Restrictions(No_Obsolescent_Features); pragma Restrictions(No_Exceptions); pragma Restrictions(No_Recursion); -- Memory management. pragma Restrictions(No_Allocators); pragma Restrictions(No_Local_Allocators); pragma Restrictions(No_Unchecked_Deallocation); --pragma Restrictions(No_); -- Make sure we don't have tasking or any of it's features enabled. pragma Restrictions(Max_Tasks => 0); pragma Restrictions(No_Protected_Types); pragma Restrictions(No_Delay); pragma Restrictions(No_Task_Hierarchy); pragma Restrictions(No_Abort_Statements); pragma Restrictions(No_Implicit_Heap_Allocations); pragma Restrictions(No_Asynchronous_Control); I'm sure there are more restrictions I can use here. So far the kernel is around 4-5KB in size when stripped, I definitely think there's more stuff to get rid of from the linker script and the gnat.adc file. My kernel will require some basic console/serial IO but I haven't decided whether to port across the IO or add in No_IO as well. I still have a number of questions regarding this feat: 1) If I use the Max_Tasks = 0, does this imply that all other tasking restrictions are also set or do I have to do this manually? i.e. I have "No_Protected_Types" enabled up there, is this done for me when Max_Tasks = 0? 2) Can anybody think of any further restrictions I can use to make sure that my kernel builds with the minimum of RT? 3) On bare hardware can I reasonably assume that System.Address = access type or do I still require the use of System.Address_To_Access_Conversions? 4) Can I reasonably use tagged types for this project? Will it require any RT packages? If so, which ones? 5) Is elaboration order still an issue for a kernel? Should my entry point be the "main" that gnatbind creates for me? But, won't that include arg[cv] (which I don't need for a kernel)? Thanks, Luke.
