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* in obtained storage location, and branch to it * copy instruction sequence SR Reg15,Reg15 Branch Reg14 to DATA1 USING DYNAREA,10 using for dynamic memory area STORAGE OBTAIN,LENGTH=(9),EXECUTABLE=NO,LOC=ANY LA 9,WALEN load memory length in Register 9 LARL 12,CONSTANTS load address relative long

IEABRCX DEFINE convert based to relative branchesīAKR 14,0 callers registers to linkage stack

Purebasic image memory allocation code#

SYSSTATE AMODE64=NO,ARCHLVL=3 gen z9+, z/OS 2.1+ bin code

Though not a requirement for this type of sample code it is a best practice in assembler coding.

Finally, the code is REENTRANT, meaning it could be loaded in a system module directory (LINKLIST, LPA), and executed simultaneously by multiple callers.

The code shows the use of the system supplied linkage stack to save caller's registers (BAKR) and restore them on return (PR), as opposed to STM/LM of the caller's register contents.

The code copies two instructions to the obtained storage and branches to it. If on a z14 or newer machine and EXECUTABLE=NO then the module will ABEND S0C4-4. The code below will execute successfully if EXECUTABLE=YES (or defaulted to), or if running on a pre z14 machine.

One of the many functions of STORAGE over GETMAIN/FREEMAIN is illustrated: EXECUTABLE=NO.

The STORAGE macro is used (PC call to the storage routine) instead of GETMAIN/FREEMAIN (SVC based.

The IEABRCX system macro will conveniently convert all based branch instructions to their relative equivalents. All modern day z/OS compilers generate baseless code, and so should the "raw assembler programmer". This is referred to as Relative addressing.

The code is "baseless", meaning no base register has been established for the entry point of the module.

PLIST EQU * 10-Byte GETMAIN/FREEMAIN Parameter ListĭC A(256) Number of Bytes Max=16777208 ((2**24)-8)ĭC X'0000' (Unconditional Request Subpool 0)Įxample below shows de facto modern day use of HLASM techniques: * DS A Address of Stg Area (Aquired or to be Freed)

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* Request to Free Storage Managed by "FREEMAIN" Supervisor Call (SVC 5) GOTSTG L Load Reg (any Reg) with Addr of Aquired Stg LA 1,PLIST Point Reg 1 to GETMAIN/FREEMAIN Parm List It’s clear that some limitations are present in the template but for most of the tasks this is a great addition to anyone’s code.* Request to Get Storage Managed by "GETMAIN" Supervisor Call (SVC 4) Because overloading doesn’t exist in PB, the constructor will be called twice (once by the template and once by yourself) if you want to define the members using said ctor, just make certain that any dynamic allocations are performed only once or you’ll have a nasty memory leak in your hands. We’re not trying to mimic any language here but rather provide a way of dealing with objects without having to write redundant code all the time. There are certain limitations that forced me to design the template as it is right now but the usage is very simple. Macros in this case are used as an aid to define templates (like you would in C++ for instance). If we decide to unregister a class, all of the objects will be freed and their respective destructors will be called. Once a class has been registered, we can create new objects and delete them at will. The usage is fairly simple: classes can be registered and unregistered. The purpose of EasyObject is mainly to encapsulate trivial and redundant code usually regarded to allocation, deallocation and keeping track of the objects. With EasyObject you can define constructors and destructors as well as iterators with ease. It allows you to register any structure as a “class”. Ok, now let’s describe this thing a little more and leave the marketing speech in the past.ĮasyObject is an object factory template for PureBasic.

Purebasic image memory allocation how to#

Third, you’re free to post any comments regarding on how to enhance it if you dear to!.

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If you open your eyes you’ll see that this is an obvious pattern but what isn’t so obvious is how do you implement a template that deals with it in an efficient and clean way within the current constraints of the language.įirst, download it. code every time you incorporate a new “class” into your project. Why should we?, let’s avoid it all together and focus our efforts in the task at hand rather than in the mundane stuff. However in essence, you end up writing pretty much the same allocate / deallocate, list, etc. Think about it, you encapsulate your structure-related code in such a way that it becomes clean, nice and tidy - in other words it makes it easy to understand what it does. Whenever you deal with structures and what have you it’s obvious that there has to be a better way of doing it.