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TMTSTUB DOS EXTENDER
--------------------
by Rustam Gadeyev, 15 May 98
INTRODUCTION
------------
TMTSTUB is based on the WDOSX 0.94 extender by TIPPACH. This extender
is intended as a replacement of PASSTUB, the PMODE-based extender, which
comes with TMT Pascal. This extender supports all functions, which are
supported by PASSTUB, but some new functions and new features are added.
The main advantage of TMTSTUB version 0.31 is its exceptions support. Because
of this a hanging program is terminated with the correct registers output.
Unlike the old PASSTUB there is function 800h of DPMI service
(MapPhysicalToLinear) is supported. This function is required for support of
LFB modes support. Note however that LFB modes are not supported by the GRAPH unit
of the restricted (free) version of TMT PASCAL. Buy the unrestricted version
to get access to LFB.
The LOGO- option in PLT.CFG disables output of the TMTSTUB logo during the
running of the emitted program.
The size of the stub-file is only 12436 bytes.
A some statistics about speed of MEMAVAIL:
program test; {$Q-,R-}
function ticks:longint;
begin
{$ifndef __TMT__}
ticks:=meml[$40:$6c];
{$else}
ticks:=memd[$40:$6c+_zero]; {the _zero variable is not required for TMTSTUB}
{$endif}
end;
var tt,i,temp:longint;
begin
i:=0;
tt:=ticks; while tt=ticks do;
tt:=ticks+20;
while tt>ticks do
begin
temp:=memavail;
temp:=memavail;
inc(i);
end;
writeln(i);
end.
Results for 20 ticks of the timer on a iPentium-133 24mb:
Raw DOS XMS(HIMEM) VCPI (EMM386, QEMM) DPMI(WIN95) Extender
PASSTUB - 30021, 6488, ???, 6, 47 PMODE3.07
DOS32 - 1235, 998, 749, 334, 47 DOS32
TMTSTUB31 - 16152, 16151, 16223, 16224, 82 WDOSX
PMWSTUB - 25571, 24107, 25544, 25563, 47 PMODE/W
BP7.0 (Prot) - 143907, 143907, 143844, 143860, 143000 RTM
BP7.0 (Real) - 1147008, 1147011, 1146926, 1147000, 1130000 real
-----------------------------------------------------------------------------
WARNING! PASSTUB will not work with IDE, which comes with TMT Pascal. You may
use this extender with unrestricted version of TMT Pascal to compile your own
programs using PLT.EXE only. Do not use TMTSTUB extender for program
debugging. You shold use PMWSTUB.EXE (PMODE/W-based extender) for program
debugging with IDE.
------------------------------------------------------------------------------
TMTSTUB API
-----------
As shown above, TMTSTUB supports all functions, which are supported
by PASSTUB extenders, but some new functions and new features are
added.
1. Supported DOS32 API (from file API.DOC by Adam Seychell)
SET CURRENT FILE POSITION V3.0+
AH = 42h
AL = origin of move
00h start of file
01h current file position
02h end of file
BX = file handle
EDX = offset from origin of new file position
Return: CF clear if successful
EAX = new file position in bytes from start of file
CF set on error
AX = error code (01h,06h)
Notes: The normal real mode DOS function uses CX:DX as the
position of the file to seek and returns DX:AX with the
new value of the position. This protected mode version
uses EDX in place of CX:DX and uses EAX in place of
DX:AX.
LOAD AND/OR EXECUTE PROGRAM V3.0+
AH = 4Bh
AL = type of load
00h load and execute
01h load but do not execute
DS:EDX -> ASCIZ program name (must include extension)
DS:EDI -> Program environment to copy for child process (copy
caller's environment if EDI = zero )
DS:ESI -> pointer to command tail to be copied into child's
PSP
Return: CF clear if successful
CF set on error
AX = error code (01h,02h,05h,08h,0Ah,0Bh)
Notes: Unlike DOS's 4Bh function this does not require a
parameter block to be set up. The environment and
command tail are pointed to by DS:EDI and DS:ESI
respectively. See the examples distributed with DOS32 on
how this function may be used. It seems that MS-DOS will
redirect the current DTA address after this function is
called. When this service is called the current DTA
address will be reset to the default area of 80h bytes
ahead the PSP address.
o The command line string is expected in the Pascal string
format. The first byte represents the number of
characters in the string followed by the actual string .
GET DOS32 ADDRESS INFORMATION V3.01+
IN: AX = EE02h
OUT: EBX = 32bit linear address of the program segment
EDX = Total size in bytes of the programs .EXE file after
linking.
ESI = Offset address of PSP ( Program Segment Prefix )
EDI = Offset address of Program Environment
ECX = Offset address of the programs .EXE file name and
path (in ASCIZ format, i.e. terminates with a zero)
AX = Real mode segment value of the 8Kb buffer that is
used by the file read/write services.
Notes:
o All offset addresses returned are relative to the main
program segment.
o The .EXE file size is generally used for loading extra data
appended to the original application's .EXE file. The
application may simply seek to this position to access the
appended data.
o The .EXE file name pointed by ECX is actually the file name
contained in the last string of the Environment segment
pointed to by EDI.
o The PSP address points to the original PSP set up by DOS.
Thus pointers stored in here still contain real mode
(segment:offset) values. Also this PSP address may not be the
same address returned by DOSs Int 21h AH=62h (Get PSP) since
DOS32 may of been loaded by a parent stub program.
o Since the segment address returned in AX points to the 8Kb
buffer used by the virtualized 32bit file read/write service
(INT 21h AH=3Fh/40h) then the contents of this buffer will be
distroyed apon call to these services. However, the
application may make temporary use of the buffer rather than
allocating a separate DOS block for transferring data between
real mode and protected mode. The near pointer of the buffer
will be equal to (16*AX - EBX)
o This function may be called in a protected mode interrupt
handler.
UNDO PREVIOUS MEMORY ALLOCATION v3.00+
This function will free the previously allocated memory
block ( function AX =EE41h ) or DMA buffer ( function AX=EE42h )
If this function is called multiple times then memory will be
deallocated in reverse order to when allocated. For example, if a
memory block was allocated followed by a DMA buffer then at first
time this function is called the DMA buffer would be freed, a
second call to this function will free the memory block, a third
call will return an error ( Carry set ) because at this point no
memory is being allocated.
IN: AX = EE40h
OUT: If function successful carry flag is cleared
If unsuccessful the carry flag is set
Notes:
o This function will fail if there is no memory allocated.
o All memory will automatically be freed when then
application terminates.
ALLOCATE A MEMORY BLOCK V3.00+
The entire application code,data and stack is initially
contained in one large memory block. This service here is used for
allocating extra memory blocks for the application.
IN: AX = EE42h
EDX = Size of the memory block requested to allocate in
bytes.
OUT: EAX = The actual allocated size of the memory block in bytes
EDX = Near pointer to the base address of the block relative
to the main program segment.
If the returned size was less than the requested size then
the Carry flag is set otherwise the carry flag is cleared.
Notes:
o The value expected in EDX will be rounded off to the next
4KB boundary. Example, allocating 51001h bytes will actually
allocate 52000h bytes.
o Never call this function in a interrupt handler or after
using the terminated and stay resident function ( AX=EE30h ).
o If EAX is returned with zero then no memory was allocated and
contents of EDX are undefined.
o The function will fail if the requested size is zero.
o No more than 64 allocations can be made. If the application
requires a faster more versatile memory management then
please use Peter Anderson's memory sub-functions from PAL
library. See example files on how to use. This function here
is should used a minimum number of times.
o When not running under a DPMI server ( i.e Raw,XMS or VCPI )
then extended memory is allocated before conventional memory
is. For example, if there is no more extended memory free
then conventional memory will be allocated. In either case
DOS32 sets up the 386 page tables such that the allocated
memory is addressed in a straight linear block when it may
actually be physically scattered throughout RAM.
Attention! Function 42h and 4Bh int 21h have other register values
for compatibility with DOS32, TMT Pascal. See above.
2. Supported WDOSX API (from README.TXT by Wuschel a.k.a Michael Tippach)
2.1. INTERRUPTS AND EXCEPTIONS
- If you're running in plain DOS without a DPMI host, WDOSX will install its -
- built in DPMI host. The following section describes the behaviour of the -
- WDOSX DPMI host in certain situations. While running under Windows etc. -
- things are depending on the DPMI host the system provides. -
If a protected mode IRQ handler has been installed by your program, hardware
interrupts occuring in real mode or V86 mode are passed up to it. Otherwise
the real (V86) mode handler is called.
WDOSX can handle a maximum mode switch nesting level of 16. This may be im-
portant to know when doing mode switches from within an IRQ handler or even
allowing an IRQ handler to be interrupted again.
All software interrupts up to 0Fh are interpreted as exceptions, so doing an
INT 5 to invoke the printscreen handler will trigger a bounds check exception
instead. You may want to use the DPMI translation services to get INT 5 doing
the expected things.
Unlike the DPMI spec says, exceptions 0..7 are not passed down to realmode.
If an exception handler has been installed by your program, it will be called
in a DPMI compliant manner. Otherwise the default handler will take over,
causing a register dump and program termination as usual.
Because your program is running on privilege level 0 when WDOSX installed its
own DPMI host, there will be no stack switch done by the CPU itself if an
exception occurs. This will cause the system to crash with a triple fault if
your program's stack is corrupted at this point. Most stack faults will crash
the machine either because of this.
Exception 0F will be passed down to real mode under any cirmstances. This is
because of a nice feature of the interrupt controller beeing able to generate
spurious IRQ 7's.
2.2. MEMORY LAYOUT
If WDOSX is running its built in DPMI host, the initial linear start address
of your program's memory block is 400000h. Under Windows etc. it can be pretty
much anywhere so don't make assumptions here.
At startup, ESP will point to to the top of the memory block, IOW accessing
the memory location at [esp] will be an invalid operation which may cause a
page fault, while accessing [esp-4] (by pushing a value etc.) is fine.
The cs: ds: (= ss:) descriptors are initialized with a limit of 4G. However,
Windows NT 3.5, for instance, does alter the descriptor limits internally. So,
if you like to know the true limits, use the LSL instruction.
Some documentations do recommend the use of negative offsets for accessing the
video memory or any other memory region in the first megabyte. Be warned that
there are some pitfalls with this method. The DPMI host is allowed to change
the linear base address of your segment if you resize it. So, your previously
calculated negative offsets will become invalid and you need to recalculate
them. A more hassle free variant is to allocate a descriptor with a base
address of 0 and a limit of 4G that'll let you access virtually anything you
want.
Never call INT 31/0503 to resize the segment you're currently running in! To
keep you away from doing this with your initial segment, I just don't tell you
the handle the DPMI host returned when WDOSX allocated the memory block.
WDOSX provides an easy to use API function (INT 21/FFFF) that lets you resize
your initial segment. It MUST be called from within your initial segment, too!
Well, it isn't a good idea to have more than one DPMI memory block either, so
what? (The debugger uses two of them, but this is another issue.)
3. THE WDOSX API
The WDOSX API could be divided into 3 parts:
- DPMI 0.9 API
- Extended INT 21H DOS API
- Other functions
Currently, almost all DPMI functions as described in the DPMI0.9 specification
are supported by WDOSX. Plus, I included function 801h due to popular demand.
If you're not familiar with DPMI, pull the spec from:
ftp://x2ftp.oulu.fi/pub/msdos/programming/specs/dpmispec.arj
The extended INT 21H is implemented in a way similar to other DOS extenders
that provide an extended INT 21H DOS API. Just to answer a FAQ: DOS functions
that do not need segment register passing in either direction can be called
directly and are thus supported "by nature"! This may sound obvious to some of
you, but it just isn't to everyone.
3.1. DPMI 0.9 FUNCTIONS SUPPORTED
0000h ALLOC LDT DESCRIPTORS
0001h FREE LDT DESKRIPTORS
0002h SEGMENT -> SELECTOR
0003h GET SELECTOR INCRMENT
0006h GET SEGMENT BASE
0007h SET SEGMENT BASE
0008h SET SEGMENT LIMIT
0009h SET ACCESS RIGHTS
000Ah CREATE ALIAS
000Bh GET DESCRIPTOR
000Ch SET DESCRIPTOR
0100h ALLOC DOS- MEM
0101h FREE DOS- MEM
0102h MODIFY DOS- MEM
0200h GET REALMODE INTERRUPT VECTOR
0201h SET REALMODE INTERRUPT VECTOR
0202h GET EXCEPTION HANDLER
0203h SET EXCEPTION HANDLER
0204h GET PM INTERRUPT VECTOR
0205h SET PM INTERRUPT VECTOR
0300h SIMULATE REAL MODE INTERRUPT
0301h CALL REALMODE PROCEDURE (RETF)
0302h CALL REALMODE PROCEDURE (IRET)
0303h ALLOCATE REALMODE CALLBACK
0304h FREE REALMODE CALLBACK
0400h GET DPMI VERSION
0500h GET FREE MEM
0501h ALLOC MEM
0502h FREE MEM
0503h RESIZE MEM
0600h LOCK LINEAR REGION
0601h UNLOCK LINEAR REGION
0602h UNLOCK REALMODE REGION
0603h RELOCK REALMODE REGION
0604h GET PHYSICAL PAGE SIZE
0702h MARK PAGE PAGEABLE
0703h DISCARD PAGE
0800h MAP PHYSICAL REGION
0801h UNMAP PHYSICAL REGION
0900h GET AND DISABLE VI STATE
0901h GET AND ENABLE VI STATE
0902h GET VI STATE
3.2. EXTENDED DOS API
Overview:
Function 09h - Write string to console
Function 1Ah - Set disk transfer area address
Function 1Bh - Get allocation information for default drive
Function 1Ch - Get allocation information for specific drive
Function 1Fh - Get drive parameter block for default drive
Function 25h - Set interrupt vector
Function 2Fh - Get disk transfer area address
Function 32h - Get drive parameter block for specific drive
Function 34h - Get address of InDos flag
Function 35h - Get interrupt vector
Function 39h - Create subdirectory
Function 3Ah - Remove subdirectory
Function 3Bh - Change current directory
Function 3Ch - Create new file
Function 3Dh - Open existing file
Function 3Fh - Read from file
Function 40h - Write to file
Function 41h - Delete file
Function 43h - Get/set file attributes
Function 44h - IOCTL
Function 47h - Get current directory
Function 48h - Allocate DOS memory block
Function 49h - Free DOS memory block
Function 4Ah - Resize DOS memory block
Function 4Bh - Load and execute child program
Function 4Eh - Find first matching file
Function 4Fh - Find next matching file
Function 56h - Rename file
Function 5Ah - Create temporary file
Function 5Bh - Create new file
- Detailed list of WDOSX extended DOS API functions:
Function 09h - Write string to console
--------------------------------------
AH = 09h
DS:EDX -> '$'-terminated string
Note: The size of the string must be less or equal 16k since this is the
transfer buffer size of WDOSX.
Function 1Ah - Set disk transfer area address
---------------------------------------------
AH = 1Ah
DS:EDX -> Disk Transfer Area
Note: WDOSX will keep an internal buffer for the DTA. Upon any Find First/
Find Next call, WDOSX does the necessary copying to make this call
transparent for the user program.
Function 1Bh - Get allocation information for default drive
-----------------------------------------------------------
AH = 1Bh
Returns
AL = sectors per cluster
CX = bytes per sector
DX = total number of clusters
DS:EBX -> media ID byte
Function 1Ch - Get allocation information for specific drive
------------------------------------------------------------
AH = 1Bh
DL = drive (0 = default, 1 = A: etc.)
Returns
AL = sectors per cluster
CX = bytes per sector
DX = total number of clusters
DS:EBX -> media ID byte
Function 1Fh - Get drive parameter block for default drive
----------------------------------------------------------
AH = 1Fh
Returns
AL = status (0 = success, -1 = invalid drive)
DS:EBX -> Drive Parameter Block
Function 25h - Set interrupt vector
-----------------------------------
AH = 25h
AL = interrupt number
DS:EDX -> new interrupt handler
Note: This function sets the protected mode interrupt vector using DPMI call
0205h.
Function 2Fh - Get disk transfer area address
---------------------------------------------
AH = 2Fh
Returns
ES:EBX -> Disk Transfer Area
Note: If no DTA address is set, the default DTA address at PSP:80h will be
returned, otherwise the return pointer is the same as last passed to
function 1Ah.
Function 32h - Get drive parameter block for specific drive
-----------------------------------------------------------
AH = 32h
DL = drive number (0 = default, 1 = A: etc.)
Returns
AL = status (0 = success, -1 = invalid drive)
DS:EBX -> Drive Parameter Block
Function 34h - Get address of InDos flag
----------------------------------------
AH = 34h
Returns
ES:EBX -> InDos flag
Function 35h - Get interrupt vector
-----------------------------------
AH = 35h
AL = interrupt number
Returns
ES:EBX -> address of interrupt handler
Note: This function returns the address of the protected mode interrupt
handler as obtained using DPMI call 0204h.
Function 39h - Create subdirectory
----------------------------------
AH = 39h
DS:EDX -> ASCIZ pathname
Returns
CF = clear on success, set on error (AX = error code)
Function 3Ah - Remove subdirectory
----------------------------------
AH = 3Ah
DS:EDX -> ASCIZ pathname
Returns
CF = clear on success, set on error (AX = error code)
Function 3Bh - Change current directory
---------------------------------------
AH = 3Bh
DS:EDX -> ASCIZ pathname
Returns
CF = clear on success, set on error (AX = error code)
Function 3Ch - Create new file
------------------------------
AH = 3Ch
CX = file attributes
DS:EDX -> ASCIZ filename
Returns
CF = clear on success (AX = file handle)
CF = set on error (AX = error code)
Function 3Dh - Open existing file
---------------------------------
AH = 3Dh
AL = access mode
DS:EDX -> ASCIZ filename
Returns
CF = clear on success (AX = file handle) set on error (AX = error
code)
Function 3Fh - Read from file
-----------------------------
AH = 3Fh
BX = file handle
ECX = number of bytes to read
DS:EDX -> data buffer
Returns
CF = clear on success (EAX = number of bytes actually read)
CF = set on error (AX = error code)
Note: This function allowes for reading up to 4 gigabytes at once (in
theory, that is.) There is no 64k limitation as in pure DOS.
Function 40h - Write to file
----------------------------
AH = 40h
BX = file handle
ECX = number of bytes to write
DS:EDX -> data buffer
Returns
CF = clear on success (EAX = number of bytes actually written)
CF = set on error (AX = error code)
Note: This function allowes for writing up to 4 gigabytes at once (in theory,
that is.) There is no 64k limitation as in pure DOS.
Function 41h - Delete file
--------------------------
AH = 41h
DS:EDX -> ASCIZ filename
Returns
CF = clear on success, set on error (AX = error code)
Function 43h - Get/set file attributes
--------------------------------------
AH = 43h
AL = subfunction (0 = get, 1 = set)
DS:EDX -> ASCIZ filename
IF AL = 1: CX = file attributes
Returns
CF = clear on success, set on error (AX = error code)
CX = file attributes
Function 44h - IOCTL
--------------------
AH = 44h
AL = subfunction
The following subfunctions are extended:
AL = 2 (read from character device control channel)
BX = file handle
ECX = number of bytes to read
DS:EDX -> buffer
Returns
CF = clear on success (EAX = number of bytes actually read)
CF = set on error (AX = error code)
Note: This function allowes for reading up to 4 gigabytes at once (in theory,
that is.) There is no 64k limitation as in pure DOS. Before calling the
actual DOS function, max (ECX,16k) bytes will be copied from DS:EDX into
the real mode transfer buffer to allow for passing request structures.
AL = 3 (write to character device control channel)
BX = file handle
ECX = number of bytes to write
DS:EDX -> data buffer
Returns
CF = clear on success (EAX = number of bytes actually written)
CF = set on error (AX = error code)
Note: This function allowes for writing up to 4 gigabytes at once (in theory,
that is.) There is no 64k limitation as in pure DOS.
AL = 4 (read from block device control channel)
BL = drive number (0 = default, 1 = A: etc.)
ECX = number of bytes to read
DS:EDX -> buffer
Returns
CF = clear on success (EAX = number of bytes actually read)
CF = set on error (AX = error code)
Note: This function allowes for reading up to 4 gigabytes at once (in theory,
that is.) There is no 64k limitation as in pure DOS. Before calling the
actual DOS function, max (ECX,16k) bytes will be copied from DS:EDX into
the real mode transfer buffer to allow for passing request structures.
AL = 5 (write to block device control channel)
BL = drive number (0 = default, 1 = A: etc.)
ECX = number of bytes to write
DS:EDX -> data buffer
Returns
CF = clear on success (EAX = number of bytes actually written)
CF = set on error (AX = error code)
Note: This function allowes for writing up to 4 gigabytes at once (in theory,
that is.) There is no 64k limitation as in pure DOS.
Function 47h - Get current directory
------------------------------------
AH = 47h
DL = drive number (0 = default, 1 = A: etc.)
DS:ESI -> 64 byte buffer to receive ASCIZ pathname
Returns
CF = clear on success, set on error (AX = error code)
Function 48h - Allocate DOS memory block
----------------------------------------
AH = 48h
BX = number of paragraphs to allocate
Returns
CF = clear on success, (AX = selector of allocated block)
CF = set on error, (AX = error code, bx = size of largest block)
Function 49h - Free DOS memory block
------------------------------------
AH = 49h
ES = selector of block to free
Returns
CF = clear on success, set on error (AX = error code)
Function 4Ah - Resize DOS memory block
--------------------------------------
AH = 4Ah
BX = new size in paragraphs
ES = selector of block to resize
Returns
CF = clear on success set on error, (AX = error code, bx = max. size
available)
Function 4Bh - Load and execute child program
---------------------------------------------
AH = 4BH
AL = 0 (other subfunctions NOT supported)
DS:EDX -> ASCIZ filename of the program to execute
ES:EBX -> parameter block (see below)
Returns
CF clear on success, set on error (AX = error code)
Note: Unlike under pure DOS, under WDOSX the format of the parameter block is
as follows:
Offset 00000000: 48 bit protected mode far pointer to evironment string to use
Offset 00000006: 48 bit protected mode far pointer to command tail to use
This is the method most other DOS extenders also use, so there should be no
significant compatibility problems.
Function 4Eh - Find first matching file
---------------------------------------
AH = 4Eh
AL = flag used by APPEND
CX = attribute mask
DS:EDX -> ASCIZ file name (may include path and wildcards)
Returns
CF = clear on success (DTA as set with function 1Ah filled)
CF = set on error (AX = error code)
Function 4Fh - Find next matching file
--------------------------------------
AH = 4Fh
DTA as set with function 1Ah contains information from previous Find
First call (function 4Eh)
Returns
CF = clear on success (DTA as set with function 1Ah filled)
CF = set on error (AX = error code)
Function 56h - Rename file
--------------------------
AH = 56h
DS:EDX -> ASCIZ filename
ES:EDI -> ASCIZ new filename
Returns
CF = clear on success, set on error (AX = error code)
Function 5Ah - Create temporary file
------------------------------------
AH = 5Ah
CX = attributes
DS:EDX -> buffer containing path name ending with "\" + 13 zero bytes
Returns
CF = clear on success, filename appended to path name in buffer (AX =
file handle)
CF = set on error (AX = error code)
Function 5Bh - Create new file
------------------------------
AH = 5Bh
CX = attributes
DS:EDX -> ASCIZ filename
Returns
CF = clear on success, (AX = file handle)
CF = set on error (AX = error code)
3.3 EXTENDED MOUSE FUNCTIONS
----------------------------
WDOSX extends the following INT 33H functions:
AX = 0009H Define Graphics Cursor
AX = 000CH Set Costum Event Handler
AX = 0016H Save Mouse Driver State
AX = 0017H Restore Mouse Driver State
Function 0009H Define Graphics Cursor
-------------------------------------
AX = 0009H
ES:EDX -> mouse pointer bitmap
BX = hot spot column
CX = hot spot row
Function 000CH Set Custom Event Handler
---------------------------------------
AX = 000CH
ES:EDX -> FAR routine
CX = call mask
Note: Calling this function with an address of 0000:00000000 will uninstall
any previously installed handler.
Function 0016H Save Mouse Driver State
--------------------------------------
AX = 0016H
ES:EDX -> state save buffer
BX = size of buffer
Function 0017H Restore Mouse Driver State
-----------------------------------------
AX = 0017H
ES:EDX -> buffer containing saved state
BX = size of buffer
3.4. OTHER WDOSX FUNCTIONS
--------------------------
INT 21H / AX = 0FFFFH "Resize Initial Memory Block"
---------------------------------------------------
AX = 0FFFFH
EDX = new size in bytes
Returns
CF = clear on success, memory block size changed and selectors fixed
CF = set on error
Note: This function is needed since a DPMI application cannot change the size
of the memory block it is currently running in. Should not be used from
inside HLL code since the runtime library will take care of memory
allocation issues and may become seriously confused about you using this
call together with malloc(), getmem() or whatsoever.
INT 31H / AX = EEFFH "DOS Extender Identification Call"
--------------------------------------------------------
AX = EEFFh
Returns
CF = clear
EAX = 'WDSX'
ES:EBX = far pointer to ASCIIZ copyright string
CH = memory allocation type (0=INT15, 1=XMS, 2=VCPI, 3=DPMI)
CL = CPU (3=386, 4=486, ... )
DH = extender major version ( currently 0 )
DL = extender minor version ( currently 94 decimal )
Note: This call is also supported by some other DOS extenders so it might
provide a resonable solution for a program to identify the underlying
DOS extender at runtime.
4. FUTURE PLANS
----------------
At the top of my current wish list there are:
1. True flat model (zero based) for the other relocatable executable formats
(the PE formats, that is), as the WATCOM variant of WDOSX already has.
The main concern is to accomplish this while staying backwards compatible
with earlier versions. However, non- relocatable formats like MZ or flat
form binary will never run with zero based descriptors since there simply
is no way to relocate these kinds of executables.
2. Improvements on the Win32 emulator. This might/might not include support
for DLLs and the ability for you to add new functions to the emulation.
This is difficult since I'll have to bring the source code for the Win32
emulator in a human readable form so I can release it.
3. A change in British law to allow public houses having still opened after
11 if (and only if) they've got Radeberger Beer (the _real_ thing!)
That's all. Enjoy!
Wuschel a.k.a Michael Tippach
Rustam Gadeyev 15 May 98