WHDLoad
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WHDLoad is a software package for the
WHDLoad makes it possible to autostart an installed floppy disk image by clicking an icon.
Two special parts are required, each one specially written for the client program: To install media, it must be read from the original disk and written to an image file on the
Slave interface
The "Slave" interface allows interaction between the program and WHDLoad, and co-ordinates the reading and writing of files. This makes it possible to run or emulate programs that are traditionally incompatible with common emulators such as
History
The primary reason for this loader is that a large number of
The first public release of WHDLoad was on September 5, 1996, and the latest available version is 18.8 released in May 2022.
Features
WHDLoad takes over the entire operating system which may cause problems with some software (e.g. TCP/IP stack),[4] but quitting the game or demo restores the system back into its normal working state.
WHDLoad games are stored on the AmigaOS file system as
How WHDLoad works
The WHDLoad "Slave" interface is integrated into the OS in such way that one can double-click a program icon to run the program at any time. When the user executes the program, by clicking a stored image icon, the AmigaOS operating system loads the WHDLoad executable and starts it. Then the loader checks the software and hardware environment, loads and checks the Slave interface required for that chosen demo or game and allocates required memory for the installed program. If the Preload feature is enabled into the requester page of WHDLoad, then the program attempts to load disk images and files into RAM (insofar as free memory is available).
At this point WHDLoad performs its main task of switching off the AmigaOS operating system, disables multitasking and interrupts, and copies memory regions which are used by AmigaOS and required by the installed program to an unused place until the AmigaOS is needed again.
WHDLoad also degrades the graphics hardware to OCS on original Amiga machines (this function actually can work also on emulated Amigas, but only on newer versions of WinUAE which recognizes WHDLoad and preserves its interrupts), then WHDLoad initializes all hardware with defined values and jumps into the Slave interface required for the program in question.
The Slave interface loads the main executable of the installed program by calling a WHDLoad function (resload_DiskLoad or resload_LoadFile), then patches the main executable (so that the loaded program will be capable of loading its data stored into the hard disk via the Slave, in order to fix compatibility problems, and to enable an exit from the program) and calls the main executable.
At this point, the program that has been installed can perform the task for which it has been written, loading its data as it would from a real floppy disk.
Users can break the execution of the loaded program by way of a "Quit" key (usually F10). When this action is performed, then the Slave interface returns to WHDLoad by calling a resload_Abort internal function.
The OS will be restored with all hardware registers and original display. The memory and all allocated resources are left free for any further usage.
Requirements
A standard
A harddisk is required, the number of games that can be installed depend on the size of the harddisk.
References
External links
- whdload.de: WHDLoad home page
- jimneray.com: X-bEnCh - A GUI to launch WHDLoad installed and other games/demos