Hide soft menus?

[Software49g]

Hello,

by rearranging and further compression of the code I was able to squeeze the new functionality into the German version of the MLP - so I believe, that this is the last beta of the message library that allows hiding the soft menus
Please report any bugs that you might find.


  MessagesEnglish.hp (Size: 88.23 KB / Downloads: 6)


This library contains also many bug fixes and speed improvements.
Note that this version will run from any port - as a matter of fact it is designed to run from a covered port without speed penalties.
However, there is still the limitation of a max. of 12 display lines (Font6/MiniFont with Header0 and the menu activated) as I am really running out of space.


Also note, that the new ChooseBoxEngine has a severe bug that will crash your machine under low memory conditions.
The ChooseBoxEngine creates some of its routines into TempOb and then creates a program that calls this routine via a pointer and that pointer is in TempOb.

This is what the ChooseBoxEngine does when a key is pressed:

1. it creates a program in TempOb and the
PTR_[in TEMPOB]ProgramCreatedIn_KeyHandler
is on Level1 of the SYS-RPL DataStack
2. Now a piece of ML code wraps this pointer from Level1 into another secondary.
:: TakeOver GetMetaVStack DROP PTR_[in TEMPOB]ProgramCreatedIn_KeyHandler 11GETLAM SetMetaVStack ;

But it is not allowed to put a pointer [in TEMPOB] into a secondary as a garbage collection will not recognize it as a referenced pointer and therefore a garbage collection might delete or move the code the pointer it referring to. For that reason, ::N (or similar SYS-RPL commands) embeds the content of a pointer into the secondary so that it is part of the secondary to be created.
Now if a garbage collection might happen in GetMetaVStack due to low memory conditions, then the garbage collection might delete or move the code the pointer it referring to and the HP 50g will crash.
Note also that this is a worst case scenario for the garbage collection as in this case it must keep track of ~ 850 catalog entries (exact number depends on installed libraries), the SYS-RPL DataStack content, the SYS-RPL ReturnStack content, additional VStacks, LAMs and further internal pointers. So garbage collection may take up to ninety seconds on a real machine!

Bugs like this are hard to find, because it will work fine unless the garbage collection happens directly inside the program (created by the ML code of the ChooseBoxEngine) before the embedded pointer.
Note again, that it is strictly forbidden having pointer in secondaries that point into TempOb. However it is save to use, if this a pointer into a memory area that is not covered by the garbage collection, e.g. ROM or absolute RAM.

This has been fixed, where the MLP/OSE uses the new ChooseBoxEngine (help entries choose list, catalog of all commands), but the error still resides in the ROM for other choose boxes called by the O.S.!

HTH+BR,
Andreas