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Operating Project Systems
Programming Project 1: Introduction to the BLITZ Tools
Due Date: 04-10-07 Overview and Goal
In this course you will be creating an operating system kernel. Youll be using the BLITZ software tools, which were written for this task. The goals of this project are to make sure that you can use the BLITZ tools and to help you gain familiarity with them.
Step 1: Print the Documentation
There are a number of documents describing the BLITZ tools. You may obtain the documents by going to the BLITZ homepage: http://www.cs.pdx.edu/~harry/Blitz/index.html From there you can access pdf versions. Print out the following documents: An Overview of the BLITZ System (7 pages) An Overview of the BLITZ Computer Hardware (8 pages) The BLITZ Architecture (67 pages) Example BLITZ Assembly Program (7 pages) BLITZ Instruction Set (3 pages) The BLITZ Emulator (42 pages) An Overview of KPL, A Kernel Programming Language (66 pages) Context-Free Grammar of KPL (7 pages) BLITZ Tools: Help Information (11 pages) The Format of BLITZ Object and Executable Files (13 pages)
Step 2: Read the Overview Document
Read the first document (An Overview of the BLITZ System) before proceeding to Step 3.
Step 3: Choose Your Host Platform
You will develop your operating system code on a host computer and you will be running the BLITZ tools on that host computer. You should decide now which host computer you will be using.
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The BLITZ tools run on either Apple Macintosh (OS X) and run on either PowerPC-based or Intel-based machine. The tools are all compiled and the executables may be downloaded and used directly. The BLITZ tools are also pre-compiled for the Sun Solaris system and may be downloaded and used directly. If you have access to any other Big-Endian, Unix-based system, you may compile the tools on that machine and use it. The BLITZ tools have not been ported to Little-Endian architectures, so you cannot use a PC. The source code for all the BLITZ tools is available, but you should not need to look at it. Nevertheless, it is available for anyone who is interested.
The BLITZ Tools
Here are the programs that constitute the BLITZ tool set. kpl The KPL compiler asm The BLITZ assembler lddd The BLITZ linker blitz The BLITZ machine emulator (the virtual machine and debugger) diskUtil A utility to manipulate the simulated BLITZ DISK file dumpObj A utility to print BLITZ .o and a.out files hexdump A utility to print any file in hex check A utility to run through a file looking for problem ASCII characters endian A utility to determine if this machine is Big or Little Endian These tools are listed more-or-less in the order they would be used. You will probably only need to use the first 4 or 5 tools and you may pretty much ignore the remaining tools. (The last three tools are only documented by the comments at the beginning of the source code files, which you may read if interested.)
Organization of the Course Material
The BLITZ system is accessible via the following URL:
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http://www.cs.pdx.edu/~harry/Blitz/ The Blitz directory contains the following material: Blitz/ ...files containing the documents mentioned above... BlitzBin/ Mac/ ...executables for the Mac host platform... Sun/ ...executables for the Sun host platform... BlitzSrc/ ...source code for the BLITZ tools... OSProject/ p1/ ...files related to project 1... p2/ ...files related to project 2... ...etc... You may access this material through the BLITZ Home page. You should also be able to ftp directly to this material.
Step 4A: For Mac Users...
Step 1: Create a directory to put the BLITZ tools into. For example, you may wish to create a directory called BlitzTools in your home directory: /Users/YourUserName/BlitzTools Then copy all the files from www.cs.pdx.edu/~harry/Blitz/BlitzBin/Mac to your BlitzTools directory. These are binary files, not text files. (I use an application called Fetch (www.fetchsoftworks.com) to do ftp file transfers.) Step 2: Set the protection bits on these programs to include executable, with a command such as: chmod ugo+rx BlitzTools/*
Step 3: Add the BlitzTools directory to your search path.
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A shell variable called PATH is maintained by your shell program and is used by the shell to locate an executable whenever a command is typed in. Details of how this variable is changed vary between the different shells. For example, the following command will get the job done for the tcsh shell: setenv PATH ${HOME}/BlitzTools:${PATH} Between each colon (:) is a directory specification. This command adds the BLITZ tools directory in front of whatever else is in the PATH. A command like this should be added to a file such as your .login file so that it will be executed every time you login. The shell builds an internal hash table that speeds up the location of programs whenever you type a command. After changing your PATH variable, youll need to restart your shell so that it uses the new PATH when builds this hash table. (Quit the Terminal application and then start Terminal back up.)
Step 4B: For Portland State University Students...
This section applies to PSU students who have an account on the shared Sun/Solaris system. All you need to do is modify your PATH variable so that your shell will search the directory containing the Blitz executables. A shell variable called PATH is maintained by your shell program and is used by the shell to locate an executable whenever a command is typed in. Details of how this variable is changed vary between the different shells. One approach might be to alter your .aliases file. You may already have a line that looks something like this: setenv PATH ${PATH}:${HOME}/bin The exact details for you may differ. (Perhaps your .aliases file does not even set the PATH variable.) Between each colon (:) is a directory specification. What you want to do is add the BLITZ tools directory in front of everything else. Add the following command after the last place PATH is set. setenv PATH ~harry/public_html/Blitz/BlitzBin/Sun:${PATH} The shell builds an internal hash table that speeds up the location of programs whenever you type a command. After changing your PATH, youll need to restart your shell so that it uses the new PATH when builds this hash table. You can log out and log back in. (In some shells you can use the command source .aliases instead.)
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Step 4C: For Users in a Shared Solaris Environment...
This section applies to users who have an account on a shared Sun/Solaris system. It is assumed that the BLITZ tools have already been downloaded by someone else and are available in some shared directory. All you need to do is modify your PATH variable so that your shell will search the appropriate directory. A shell variable called PATH is maintained by your shell program and is used by the shell to locate an executable whenever a command is typed in. Details of how this variable is changed vary between the different shells. One approach might be to alter your .aliases file. You may already have a line that looks something like this: setenv PATH ${PATH}:${HOME}/bin The exact details for you may differ. (Perhaps your .aliases file does not even set the PATH variable.) Between each colon (:) is a directory specification. What you want to do is add the BLITZ tools directory in front of everything else. Assume that the directory with the BLITZ tools is called: ~instructorUserid/BlitzTools Be sure to get the exact directory name before proceeding. Then add the following command after the last place PATH is set. setenv PATH ~instructorUserid/BlitzTools:${PATH} The shell builds an internal hash table that speeds up the location of programs whenever you type a command. After changing your PATH, youll need to restart your shell so that it uses the new PATH when builds this hash table. You can log out and log back in. (In some shells you can use the command source .aliases instead.)
Step 4D: For Users in Some Other Unix/Linux Environment...
This section applies to users who have a Unix/Linux box and wish to download and re-compile the BLITZ tools for their machine. Step 1: Create a directory to put the BLITZ source code into. For example, you may wish to create a directory called BlitzSrc in your home directory: ~YourUserName/BlitzSrc Then copy all the files from
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www.cs.pdx.edu/~harry/Blitz/BlitzSrc to your BlitzSrc directory. There is a single subdirectory called www.cs.pdx.edu/~harry/Blitz/BlitzSrc/kpl so your BlitzSrc directory will also have a subdirectory, called: ~YourUserName/BlitzSrc/kpl Step 2: Compile the C programs in: ~YourUserName/BlitzSrc There are two makefiles available, called ~YourUserName/BlitzSrc/makefile-Mac ~YourUserName/BlitzSrc/makefile-Solaris They are quite similar. For example, if you are working on a Solaris system, youll want to use the Solaris makefile, so type: mv makefile-Solaris makefile Next, type: make This should invoke the C compiler to produce the following executables: asm lddd blitz diskUtil dumpObj hexdump check endian Next, go into the kpl subdirectory and compile the kpl compiler: cd kpl mv makefile-Solaris makefile make This should invoke the C++ compiler to produce a single executable called: Page 6
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kpl Step 3: Create a directory to put the executables into: mkdir ~YourUserName/BlitzTools Move all the executables into the directory you just created: cd ~YourUserName/BlitzSrc mv asm lddd blitz diskUtil dumpObj hexDump check endian \ ~YourUserName/BlitzTools cd ~YourUserName/BlitzSrc/kpl mv kpl ~YourUserName/BlitzTools Step 4: Add the BlitzTools directory to your search path. A shell variable called PATH is maintained by your shell program and is used by the shell to locate an executable whenever a command is typed in. Details of how this variable is changed vary between the different shells. For example, the following command will get the job done for the tcsh shell: setenv PATH ${HOME}/BlitzTools:${PATH} Between each colon (:) is a directory specification. This command adds the BLITZ tools directory in front of whatever else is in the PATH. A command like this should be added to a file such as your .login file so that it will be executed every time you login. The shell builds an internal hash table that speeds up the location of programs whenever you type a command. After changing your PATH variable, youll need to login again, so your shell will use the new PATH when builds this hash table.
Step 5: Verify the Tools Work
At the UNIX prompt, type the command. kpl You should see the following: ***** ERROR: Missing package name on command line 1 error detected! **********
**********
If you see good. this, If you see anything else, then something is wrong.
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Step 6: Set up a Directory for Project 1
Create a directory in which to place all files concerned with this class. We recommend a name matching your course number, for example: ~YourUserName/cs333 Create a directory in which to place the files concerned with project 1. We recommend the following name: ~YourUserName/cs333/p1 Copy all files from: http://www.cs.pdx.edu/~harry/Blitz/OSProject/p1/ to your cs333/p1 directory.
The BLITZ Assembly Language
In this course you will not have to write any assembly language. However, you will be using some interesting routines which can only be written in assembly. All assembly language routines will be provided to you, but you will need to be able to read them. Take a look at Echo.s and Hello.s to see what BLITZ assembly code looks like.
Step 7: Assemble, Link, and Execute the Hello Program
The p1 directory contains an assembly language program called Hello.s. First invoke the assembler (the tool called asm) to assemble the program. Type: asm Hello.s This should produce no errors and should create a file called Hello.o. The Hello.s program is completely stand-alone. In other words, it does not need any library functions and does not rely on any operating system. Nevertheless, it must be linked to produce an executable (a.out file). The linking is done with the tool called lddd. (In UNIX, the linker is called ld.) lddd Hello.o o Hello Normally the executable is called a.out, but the -o Hello option will name the executable Hello. Finally, execute this program, using the BLITZ virtual machine. (Sometimes the BLITZ virtual machine is referred to as the emulator.) Type:
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blitz g Hello The -g option is the auto-go option and it means begin execution immediately. You should see:
Beginning execution... Hello, world! **** A 'debug' instruction was encountered ***** Done! The next instruction to execute will be: 000080: A1FFFFB8 jmp 0xFFFFB8 ! targetAddr = main Entering machine-level debugger... ====================================================== ===== ===== ===== The BLITZ Machine Emulator ===== ===== ===== ===== Copyright 2001-2006, Harry H. Porter III ===== ===== ===== ====================================================== Enter a command at the prompt. info about commands. > Type 'quit' to exit or 'help' for
At the prompt, quit and exit by typing q (short for quit). You should see this:
> q Number of Disk Reads Number of Disk Writes Instructions Executed Time Spent Sleeping Total Elapsed Time = = = = = 0 0 1705 0 1705
This program terminates by executing the debug machine instruction. This instruction will cause the emulator to stop executing instructions and will throw the emulator into command mode. In command mode, you can enter commands, such as quit. The emulator displays the character > as a prompt. After the debug instruction, the Hello program branches back to the beginning. Therefore, if you resume execution (with the go command), it will result in another printout of Hello, world!.
Step 8: Run the Echo Program
Type in the following commands: asm Echo.s lddd Echo.o o Echo blitz Echo
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On the last line, we have left out the auto-go -g option. Now, the BLITZ emulator will not automatically begin executing; instead it will enter command mode. When it prompts, type the g command (short for go) to begin execution. Next type some text. Each time the ENTER/RETURN key is pressed, you should see the output echoed. For example: > g Beginning execution... abcd abcd this is a test this is a test q q **** A 'debug' instruction was encountered ***** Done! The next instruction to execute will be: cont: 0000A4: A1FFFFAC jmp 0xFFFFAC ! targetAddr = loop > (For clarity, the material entered on the input is underlined.) This program watches for the q character and stops when it is typed. If you resume execution with the go command, this program will continue echoing whatever you type. The Echo program is also a stand-alone program, relying on no library functions and no operating system.
The KPL Programming Language
In this course, you will write code in the KPL programming language. Begin studying the document titled An Overview of KPL: A Kernel Programming Language.
Step 9: Compile and Execute a KPL Program called HelloWorld
Type the following commands: kpl -unsafe System asm System.s kpl HelloWorld asm HelloWorld.s asm Runtime.s lddd Runtime.o System.o HelloWorld.o -o HelloWorld There should be no error messages.
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Take a look at the files HelloWorld.h and HelloWorld.c. These contain the program code. The HelloWorld program makes use of some other code, which is contained in the files System.h and System.c. These must be compiled with the -unsafe option. Try leaving this out; youll get 17 compiler error messages, such as: System.h:39: ***** ERROR at PTR: Using 'ptr to void' is unsafe; you must compile with the 'unsafe' option if you wish to do this
Using the UNIX compiler convention, this means that the compiler detected an error on line 39 of file System.h. KPL programs are often linked with routines coded in assembly language. Right now, all the assembly code we need is included in a file called Runtime.s. Basically, the assembly code takes care of: Starting up the program Dealing with runtime errors, by printing a message and aborting Printing output (There is no mechanism for input at this stage... This system really needs an OS!) Now execute this program. Type: blitz g HelloWorld You should see the Hello, world... message. What happens if you type g at the prompt, to resume instruction execution?
The makefile
The p1 directory contains a file called makefile, which is used with the UNIX make command. Whenever a file in the p1 directory is changed, you can type make to re-compile, re-assemble, and relink as necessary to rebuild the executables. Notice that the command kpl HelloWorld will be executed whenever the file System.h is changed. In KPL, files ending in .h are called header files and files ending in .c are called code files. Each package (such as HelloWorld) will have both a header file and a code file. The HelloWorld package uses the System package. Whenever the header file of a package that HelloWorld uses is changed, HelloWorld must be recompiled. However, if the code file for System is changed, you do ...