EMU2: A simple text-mode x86 + DOS emulator
This is a simple DOS emulator for the Linux text console, supporting basic DOS system calls and console I/O.
Using the emulator
To run a DOS .exe or .com file, simply load it with
emu2 myprog.exe
The emulator accepts some options in the command line and more options as environment variables, this allows child process (programs run by your DOS program) to inherit the configuration.
The full usage is:
emu2 [options] <prog.exe> [args...] [-- environment vars]
Options (should be placed before the DOS program name):
-
-hShows a brief help. -
-b addrLoad header-less binary at given address (to load ROMs or test data). -
-r <seg>:<ip>Specify a run address to start execution (only for binary loaded data).
The available environment variables are:
-
EMU2_DEBUG_NAMEBase name of a file to write the debug log, defaults to the exe name if not given. -
EMU2_DEBUGList of debug options to activate, from the following:cpu,int,port,dos,video. -
EMU2_PROGNAMEDOS program name, if not given try to convert the unix name to an equivalent DOS path. -
EMU2_DEFAULT_DRIVEDOS default (current) drive letter, if not given useC: -
EMU2_CWDDOS current working directory, if not given tries to convert the current directory to the equivalent DOS path inside the DOS default drive, orC:\if not possible. -
EMU2_DRIVE_n Set unix path as root of driven, by default all drives point to the unix working directory. -
EMU2_APPENDSets a list of paths to search for data files on open, emulating the DOSAPPENDcommand. Only files with a relative path are included in the search, and the search is relative to the current working directory if no drive letter is specified in the append path. For example, if set to "TXT;C:\IN", when opening the file "CAT.TXT" the file is searched as "CAT.TXT", "TXT\CAT.TXT" and "C:\IN\CAT.TXT" in turn. -
EMU2_CODEPAGESet DOS code-page to the specified string. Set to '?' to show list of included code-pages, multiple aliases separeted with commas. Set to a file name to read the mapping table from a file with the unicode value for each byte. You can download mapping tables from ftp://ftp.unicode.org/Public/MAPPINGS/VENDORS/MICSFT/PC/ The code-page setting affects keyboard input and screen output, but does not change the DOS NLS information. The default code-page is CP437. -
EMU2_LOWMEMLimits main memory to 512KB, this fixes some old DOS programs with a bug that checks available memory using "signed" comparison insructions (JLE instead of JBE). This is needed at least for MASM versions 1.0 and 1.10.
Simple Example
For a simple example, we can run the Turbo Pascal 3, available from the antique
software collection as a file tp302.zip.
First, make a new directory and unzip the file:
$ mkdir tp302
$ cd tp302
$ unzip ../tp302.zip
$ ls
$ ls
$ ls
ACCESS3.BOX CALC.PAS DEMO-BCD.PAS GRAPH.P SUBDIR.PAS TURBO.COM
ART.PAS CMDLINE.PAS EXTERNAL.DOC LISTER.PAS TINST.COM TURBO.MSG
CALCDEMO.MCS COLOR.PAS GETDATE.PAS README TINST.MSG TURTLE.PAS
CALC.HLP DEMO1-87.PAS GETTIME.PAS README.COM TURBO-87.COM WINDOW.PAS
CALC.INC DEMO2-87.PAS GRAPH.BIN SOUND.PAS TURBOBCD.COM
$ chmod +w *
The last is necessary as you will want to to modify the program files afterwards.
The main file is named "TURBO.COM", there is also a "README.COM" to read further info, try that:
$ emu2 README.COM
You can press exit to return to the command line. Now, you can configure the compiler,
as the README said, just load TINST.COM, press "S" (screen type), "0" (default), "N"
(screen does not blink) and "Q" to quit.
$ emu2 TINST.COM
TURBO Pascal installation menu.
Choose installation item from the following:
[S]creen type | [C]ommand installation | [M]sg file path | [Q]uit
Enter S, C, M or Q:
Choose one of the following displays:
0) Default display mode
1) Monochrome display
2) Color display 80x25
3) Color display 40x25
4) b/w display 80x25
5) b/w display 40x25
Which display? (Enter no. or ^Q to exit):
Does your screen blink when the text scrolls? (Y/N):
Finally, we are ready to run the program:
$ emu2 TURBO.COM
----------------------------------------
TURBO Pascal system Version 3.02A
PC-DOS
Copyright (C) 1983,84,85,86 BORLAND Inc.
----------------------------------------
Default display mode
Include error messages (Y/N)?
Logged drive: C
Active directory: \
Work file:
Main file:
Edit Compile Run Save
Dir Quit compiler Options
Text: 0 bytes
Free: 62024 bytes
>
Try loading a program, use "e" to edit, type "window.pas", and you are in the editor:
Line 1 Col 1 Insert Indent C:WINDOW.PAS
program TestWindow;
{$C-}
{
WINDOW DEMONSTRATION PROGRAM Version 1.00A
This program demonstrates the use of windows on the IBM PC
and true compatibles.
PSEUDO CODE
1. MakeWindow - draws window boxes on the screen
2. repeat
UpdateWindow 1 - scrolls the window contents up or
down for each window.
UpdateWindow 2
UpdateWindow 3
until a key is pressed
3. Reset to full screen window
INSTRUCTIONS
1. Compile this program using the TURBO.COM compiler.
2. Type any key to exit the program.
}
To exit the editor, type "CONTROL+K" and "D", in the prompt you can now type "R" to compile and run the program.
Advanced Example
For a more advanced example, we can install and run Turbo Pascal 5.5, available from the same
antique software collection as a file tp55.zip.
First, make a new directory and unzip the file:
$ mkdir tp55
$ cd tp55
$ unzip ../tp55.zip
$ ls
Disk1 Disk2
As you see, the program was distributed in two disks, and must be installed before running.
To install, let's first copy all the contents to one directory:
$ mkdir all
$ cp -r Disk1/* Disk2/* all/
And now, run the emulator giving the correct paths to simulate a floppy drive:
$ EMU2_DEFAULT_DRIVE=A EMU2_DRIVE_A=all emu2 all/INSTALL.EXE
Type enter, enter again to install from drive "A", again to install on a hard-drive, go down to "Start Installation" and enter again. The install program shows an error, this is because we copied all the content to one drive. Simply type "S" to skip all errors.
After the installation is finished, we must run the install again, to copy the missing files from before, with the same command line:
$ EMU2_DEFAULT_DRIVE=A EMU2_DRIVE_A=all emu2 all/INSTALL.EXE
Again, press enter to the questions and go to "Start Installation", this time will complete without errors.
You can now compile from the command line, as:
$ emu2 tp/tpc.exe -- 'PATH=C:\TP'
Turbo Pascal Version 5.5 Copyright (c) 1983,89 Borland International
Syntax: TPC [options] filename [options]
/B Build all units /$A- No word alignment
/Dxxx Define conditionals /$B+ Complete boolean evaluation
/Exxx EXE & TPU directory /$D- No debug information
/Fxxx Find run-time error /$E- No 8087 emulation
/GS Map file with segments /$F+ Force FAR calls
/GP Map file with publics /$I- No I/O checking
/GD Detailed map file /$L- No local debug symbols
/Ixxx Include directories /$Mxxx Memory allocation parameters
/L Link buffer on disk /$N+ 8087 code generation
/M Make modified units /$O+ Overlays allowed
/Oxxx Object directories /$R+ Range checking
/Q Quiet compile /$S- No stack checking
/Txxx Turbo directories /$V- No var-string checking
/Uxxx Unit directories
/V EXE debug information
$ emu2 tp/tpc.exe tp\\qsort.pas -- 'PATH=C:\TP'
Turbo Pascal Version 5.5 Copyright (c) 1983,89 Borland International
TP\QSORT.PAS(66)
66 lines, 4384 bytes code, 2668 bytes data.
$ emu2 tp/qsort.exe
....
And for the IDE, you can use:
emu2 tp/turbo.exe -- 'PATH=C:\TP'
