What is required of a resident application?

[Leffmann]

Obviously it has to be reentrant, but are there any other restrictions as far as hunk types, BSS space etc. go?

Also, do Kick 1.2 and 1.3 have the resident feature or is it for 2.0+ only? And how did Commodore intend for developers to mark their applications as pure? The pure-flag is not available when you show icon information in the Workbench, and I can't recall seeing any compiler or linker that can set the flag on its output.

[meega]

Try the CLI (Protect +/- hsparwed).

Ed: oh, don't mark it Pure if it isn't, it won't help.

Ed2: Pure code is pure code - no data. You can make things resident even if they aren't pure by using the FORCE keyword (there may be alternatives) which will strip the executable from any data hunks, and allows some things to be resident when they ordinarily wouldn't be. Someone else who really knows about this stuff should correct or continue here.

Ed3: if you want to know if it's in wb1.3, look in the C: drawer. If Resident is present, then you should be able to use it.

Ed4: I think DICE could create Pure executables, with the bit set, but I'm a little hazy on that.

[Toni Wilen]

BSS space in re-entrant application does not make sense because it can't be used for storing data if you want to keep it re-entrant

[Leffmann]

Ed2: Pure code is pure code - no data.

So separate hunks for constant data is not allowed, and thus reloc entries are not allowed as well? Even if they are within that same, single code hunk?

BSS space in re-entrant application does not make sense because it can't be used for storing data if you want to keep it re-entrant

Technically you could make use it for one-time initialization of data.

Anyway, is there any exhausting document on this? Maybe I've been looking in the wrong place, but the reason I posted here is because I haven't been able to find anything about this anywhere.

Thanks

[Toni Wilen]

Relocation is fine, program is loaded only once but program's hunk contents (whatever the type of hunk) must not be modified.

All data space must be allocated dynamically, usually single memory block is allocated with AllocMem() and stored to A4 or A5 and all data accesses are relative to A4/A5.

Technically you could make use it for one-time initialization of data.

Remember to disable multitasking during initialization or bad things can happen if someone runs your program again while previous one is still running one-time initialization

[meega]

Offtopic: There are other uses for the protection bits than just the recomended ones. I used to mark text files as pure (protect blah:file.whatever +p) to show that I'd printed them.

[matthey]

Originally Posted by meega

Offtopic: There are other uses for the protection bits than just the recomended ones. I used to mark text files as pure (protect blah:file.whatever +p) to show that I'd printed them.

Some are not so well known. For example, the h bit doesn't stand for hidden but for hold. A pure program with the h bit set will stay resident in memory when executed. Set the hold bits and remove lines like this...

Resident >NIL: Assign PURE

This will speed up the startup-sequence and make scripts faster if you have the memory to spare.

One note on making resident programs. It is ok to have data sections or data in your code sections but it can only be read and not written. The stack is commonly used for temporary storage as well as functions that allocate storage. Each program instance gets a new stack.

Relocs are fine. All the relocations take place before any programs use the code. The relocs and the code locations do not change after loadseg.