v2.20

HDPMI

- ixed: pmstate variable moved to client-specific data region. This
bug was virtually irrelevant up to v3.19, but there it may have caused
a crash followed by DOS memory corruption.

- fixed: in int 21h, ax=4Bh translation, try to translate only if al=0,
as it is and was documented.

- fixed: in v3.19, if HDPMI=32 wasn't set, the required DOS memory was
reported too high if at least one client was already active.

- fixed: raw mode switches to protected-mode didn't set a helper variable
that's used to distinguish IRQs and exceptions. As a consequence,
exceptions were then treated as IRQs, causing a crash.

- int 25h/26h, displays in debug version: register esi was modified!

- set error status ax=0211h if int 25h/26h TLB overflow occurs.

- int 25h/26h and int 21h, ax=7305h transfer limit was actually
7.5 kB, since a part of the TLB was used for the diskio packet.
This is now copied to the RMS, so the full TLB is used for sector
transfers.

- if exception occurs inside the host's default exception handling
( that tries to execute an int 21h, ax=4Cffh ), the client will
be killed ( and the host, if installed residently, will terminate,
if possible ).

- vendor API "HDPMI" now available in release version. Allows to
"disable" host or to switch on/off HDPMI=32.

- a disabled host will be reenabled when a client terminates.

- the HDPMI variants that run clients with IOPL=0 have now a full
8 KB IOPB, zeroed. They are included in HXRT, with an "i"-suffix.

- enabled kernel debug API for the standard version.

- port trapping API added for HDPMI variants that run clients with IOPL=0.

- fixed: exc 0Dh in ring 0 for hdpmi16 was not detected reliably.


DPMILD32:

- bugfix: the last few bytes of DPMILD32's exit code was executed as 32-bit,
although the code was actually 16-bit; as a result, a wrong DOS exit
code was returned.

- ensure the alias descriptor has a limit of -1 when accessing an MCB.

- bugfix: terminating in NTVDM caused fault if DPMILDR=2 wasn't set.

- cleaned debug displays.

- switch DPMILDR=1 removed. Instead, the loader detects if a debugger
is present via Int 41h and runs an Int 3 before program entry.

- bugfix: changing value of DPMILDR=8 by API int 21h, ax=4b94h may have
caused the loader not to release the PSP and environment of a task.

- switch DPMILDR=256 removed (loading NE dll DEBUGO32.DLL).

DKRNL32

- allow file size > 2 GB if not running on NT platforms

- GetLargestConsoleWindowSize: if current cols exceed "max", use current
BIOS values for rows & cols.

- SetConsoleScreenBufferSize will accept current video params.

- int 41h, ax=159h: don't just return, but route this call to next handler.

- if debugger has been detected, don't handle Int 01 or Int 03.

- fixed: if application had no heap, GetCommandLine() failed.

- fixed: IRQ 1 handler didn't always enable interrupts before IRET; if
running with IOPL=0, this may have caused the application to "hang".

- fatal exit if dkrnl32's exception handler detects a non-zero-based SS
segment.