Enhancements to Dosbox Debugger for Track Port

The Dosbox debugger has received several enhancements that improve its functionality and stability, particularly in regards to track port operations. These changes have been implemented in various areas of the codebase, including src/dos/dos_execute.cpp, src/ints/bios_keyboard.cpp, src/ints/int10_char.cpp, src/dos/dos_devices.cpp, src/dos/dos_files.cpp, and more.

One notable enhancement is the fix for small COM program execution on PCjr machine type in src/dos/dos_execute.cpp. This change ensures that these programs can run correctly within Dosbox. Additionally, the BIOS memory now indicates when a keyboard ACK has been received, as implemented in src/ints/bios_keyboard.cpp. Furthermore, page numbers are ignored for modes with only one page, which resolves an issue with certain programs.

In another improvement, src/ints/int10_char.cpp now uses real pointers with font data to read characters, just like it does when writing characters. This change has been made in the spirit of consistency and has resolved a specific problem with installing World Series of Poker.

Other notable enhancements include:

* Preserving last error code when no error occurs (src/dos/dos_devices.cpp)

* Fixing 'Invalid Access Code' errors when opening files (src/dos/dos_files.cpp)

* Updating Drive Parameter Table only when necessary

* Preventing problematic conditions such as booting floppy image files when floppy images are mounted

* Improving AT drive handling, particularly in regards to zero-length file truncation

These changes also address issues with installing various games and programs, including Amberstar, Dark Seed, Gods, Master of Magic, and more. The Dosbox team has taken steps to improve low-level hacks for local drive HDD when floppy images are mounted, which has resolved specific problems with multi-floppy installers.

The Drive system has undergone several improvements as well, including minor corrections related to r4477 (src/dos/dos.cpp, src/ints/bios_disk.cpp). Additionally, the handling of invalid encodings of the BOUND instruction has been corrected in src/cpu/core_full/op.h and other files.

Finally, Dosbox now pushes registers for most DOS function calls, which prevents a bug in UNLZEXE from causing a crash. This change may also help with other buggy programs and unusual cases (src/cpu/callback.cpp, src/dos/dos.cpp, src/dos/dos_execute.cpp).

These enhancements demonstrate the ongoing commitment of the Dosbox team to improving the performance and functionality of their debugger. With these updates, users can expect improved stability and compatibility when working with track port operations in Dosbox.

Dosbox debugger track port