Subject: 1. Introduction and Intent
go General Section for Details
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Part I 1. Introduction and Intent 2. Table of Contents 3. Charters For comp.lang.asm.x86 and alt.lang.asm Newsgroups ** 4. What is Assembly Language ** 5. List of x86 OpCodes ** 6. What is HELPPC and Where It Is Available ** 7. How To Truncate a File 8. How Can STDERR Be Redirected To a File 9. How To Determine the CPU Type 10. IRQ Assignments 11. Ralf Brown's Interrupt List REVISED 12. Using VGA Mode 13h for Fast Graphics 13. Protected Mode REVISED 14. Shareware ASM Libraries Part II 15. Accessing 4 Gegs of Memory in Real Mode 16. What Is Available at developer.intel.com 17. Interrupts and Exceptions 18. ASM Books Available 19. ASM Code Available on Internet 20. How To Commit a File 21. Using Extended Memory Manager 22. EXE2BIN Replacement 23. ASM Tutorials Available on the Internet 24. Shareware Assemblers REVISED 25. Undocumented OpCodes Part III 26. WWW Assembly HomePages 27. Common Reason Why Memory Allocation Fails 28. Volume Serial Numbers 29. .obj File Format 30. Rebooting from Software 31. Other FAQs 32. Pseudo Random Number Generator in Assembly Language 33. Command Line Arguments 34. Free 32-bit and DJGPP 35. TERSE Programming Language 36. Assembly Language IDEs REVISED 37. Disassemblers 38. How to Optimize for the Pentium 39. Assembly Language Programming Style Guidelines 40. Other Assembly-Related Newsgroups 41. ZD-86 Debugger 42. Acknowledgments [General][MASM][TASM][A86/D86]------------------------------
Subject: 7. How To Truncate A File
There is not any single DOS Int 21h function that performs this operation. A file can be truncated using two functions. The procedure is: 1. Use Int 21h function 42h, Move File Pointer, to move the file pointer to the position where you want the file to be truncated. 2. Use Int 21h function 40h, Write File or Device, to write zero bytes to the file. Execution of the last DOS function will update the directory to the new file length. Contributor: Raymond Moon, raymoon@moonware.dgsys.com Last changed: 28 Dec 94 Return to the Table Of Contents------------------------------
Subject: 8. How Can STDERR Be Redirected To A File
I understand that 4DOS has this capability at its command line. If you are looking in the assembly language FAQ for this information, an assembly language answer probably is desired. Here it is. You will need to write a short program that performs the STDERR redirection before loading and executing the desired program. This loader program relies upon the fact that a child program inherits all open files of the parent program unless the parent program opens a file with the inheritance flag set to no. Because the full code for such a program is too large for this FAQ, I will give the salient specifications for such a program. 1. The loader program accepts three command line arguments: a. The full path and filename of the file into which STDERR is to be written. b. The full path and filename of the program to be executed. c. The command line for the program to be executed (should be delimited by double quotes to allow multiple arguments). This argument is optional. 2. Release all memory above the program using Int 21 function 4ah so that there will be room enough to load and execute the designated program. 3. Open the file from step 1.a above into which STDERR is to be written. 4. Duplicate STDERR filehandle, which is 2, using Int 21h function 45h. 5. Using Int 21h function 46h, force STDERR filehandle, again 2, to have the filehandle of the opened file from step 2. 6. Use Int 21h function 4b00h to load and execute the program from step 1.a. Use the default environment and the command line from step 1.c above. 7. Upon return from the function 4b00h, close the file opened in step 2. 8. To restore STDERR, use Int 21h function 46h to force STDERR, again 2, to point to the filehandle saved from step 3 above. This same technique can be applied to any of the standard devices. I have written a full featured demonstration program. I believe that asm programmers will find the source code useful even if they do not want to redirect stderr to a file. The URL to the file is: ftp://ftp.simtel.net/pub/simtelnet/msdos/asmutl/stderrf.zip Contributor: Raymond Moon, raymoon@moonware.dgsys.com Last changed: 3 Jun 95 Return to the Table Of Contents------------------------------
Subject: 9. How To Determine The CPU Type
9.1 CPUID PROGRAM The type of processor and math coprocessor can be determined using two functions that have been provided by Intel. The source code to these functions can be obtained from Intel by: ftp://ftp.intel.com/pub/IAL/tools_utils_demos/cpuid3.zip Three source files are included in this .zip file. cpuid3a.asm - This source code file contains two assembly language functions. One determines the type of cpu from 8088/8086 to Pentium. The second detects and identifies, if present, the type of math coprocessor. cpuid3b.c - a c program that calls the above two functions and displays the results. cpuid3c.asm - this is an assembly program equivalent to cpuid3b.c. 9.2 AP-485 INTEL PROCESSOR IDENTIFICATION WITH THE CPUID INSTRUCTION This Application Note explains how to use the CPUID instruction in software applications, BIOS implementations, and various processor tools. By taking advantage of the CPUID instruction, software developers can create software applications and tools that can execute compatibly across the widest range of Intel processor generations and models, past, present, and future. http://developer.intel.com/design/pro/applnots/241618.HTM 9.3 Robert Collins' CPUID.ASM Robert Collins has written two columns for Dr. Dobb's Journal on this subject. These articles with source code is available on his web site: Part 1: http://www.x86.org/ddj/Sep96/Sep96.html Part 2: http://www.x86.org/ddj/Nov96/Nov96.html 9.4 Grzegorz Mazur's x86 CPU Identification Grzegorz has a series of hypertext articles that explain x86 CPU identification algorithms developed by himself. Covered are not only the Intel chips but also V20, V30 (remember them), and Cyrix. His page is located: http://grafi.ii.pw.edu.pl/gbm/x86/index.html Contributor: Raymond Moon, raymoon@moonware.dgsys.com Last changed: 18 Mar 97 Return to the Table Of Contents------------------------------
A list of IRQ assignments are available in David Jurgens' HELPPC database. See Subject #6 for details on how to obtain this program. Contributor: Raymond Moon, raymoon@moonware.dgsys.com Last changed: 28 Dec 94 Return to the Table Of Contents------------------------------
Subject: 11. Ralf Brown's Interrupt List REVISED
11.1 FILE AVAILABILITY The latest version of Ralf Brown's Interrupt List is 5.9, dated 30 Jun 98. The files are available directly from his home page, from SimTel, or Garbo: http://www.cs.cmu.edu/afs/cs.cmu.edu/user/ralf/pub/WWW/files.html ftp://ftp.simtel.net/pub/simtelnet/msdos/info ftp://garbo.uwasa.fi/pc/programming The files are: inter59a.zip Comprehensive listing of interrupt calls, 1of4 inter59b.zip Comprehensive listing of interrupt calls, 2of4 inter59c.zip Comprehensive listing of interrupt calls, 3of4 inter59d.zip Comprehensive listing of interrupt calls, 4of4 inter59e.zip Utility programs/source code for interrupt list inter59f.zip WinHelp conversion programs for interrupt list inter59g.zip Hypertext conversion programs for interrupt list 11.2 DESCRIPTION The interrupt list is a comprehensive listing of functions available through interrupt calls and FAR calls, both documented and (officially) undocumented, plus maps of CMOS and BIOS memory, I/O ports, I2C-bus devices, and System Management Mode save areas. This release contains more than 9200 entries and over 5000 tables 11.3 WHAT IS NEW Nearly 400k of updates, including Intel 440EX/X and 82371MX chipsets, OPTi "Vendetta" and 82C493/82C382 chipsets, Via VT82C496G and VT82C570M "Apollo Master" chipset, PicoPower Vesuvius chipset, C&T 82C9001A and 64200/64310 video chips, Ensoniq ES1370/1371 sound chips, Cirrus CL-PD6710/22/29 network adapters, Award-BIOS password algorithm, more PCI vendor IDs, and a substantially expanded OPCODES.LST (now including instruction timing tables for most CPUs). Also added a new viewer for use under MS Windows (in inter59e). 11.4 OTHER INCLUDED GEMS OVERVIEW.LST - A brief description of each of the 256 interrupts. 86BUGS.LST - A list of undocumented and buggy instructions with descriptions of the x86 Intel processor and compatible processors. And you thought that the Intel FDIV was the first bug in a processor! CMOS.LST - a CMOS memory map. OPCODE.LST - A list of undocumented instructions and documented instructions of any last processor. PORTS.LST - I/O port addressed for XT, AT and PS/2 computers. GLOSSARY.LST - glossary of PC terms. MEMORY.LST - The format for various memory locations, such as the BIOS Data Segment, Interrupt Vector Table, and much, much more. INTERRUP.PRI - iAPX 86 Interrupt Primer Contributor: Raymond Moon, raymoon@moonware.dgsys.com Last changed: 5 Sep 98 Return to the Table Of Contents------------------------------
Subject: 12. Using VGA Mode 13h for Fast Graphics
12.1 INTRODUCTION AND PREPARATION Mode 13h is so widely used for graphics applications in DOS because it is very easy to use. The screen is constantly being redrawn by the video card. To affect what the card draws, it is necessary to write to the screen buffer. The screen buffer in mode 13h is always at segment:offset = A000:0000. Thus, to set up drawing directly to the video buffer, this is what you'd most often first do: ;Change the video mode to 13h xor ah, ah ;VIDEO Function 00h: Change screen mov al, 13h ;Put the desired graphics mode into AL int 10h ;Call VIDEO ;Prepare for writing to the video buffer mov di, 0a000h ;Put the video segment into DI mov es, di ; so it can easily be put into ES xor di, di ;Start writing at coordinates (0,0) 12.2 WRITING PIXELS TO THE SCREEN Why is Mode 13h so popular? To understand, you must know a few basic facts. In Mode 13h, the screen is 320 by 200, or 320 pixels across and 200 pixels down. In each pixel, there's a possibility of 256 colors, which can be fit into one byte. Thus, 320*200*1 = 64000 bytes, about the size of one segment. Think of the screen as an array of colors. The first row takes up addresses A000:0000 to A000:013F (decimal 319), the second row takes up addresses A000:0140 to A000:027F (decimal 639), and so on. To plot a pixel, assuming ES=A000: ;Plot a pixel in video mode 13h, where ;PixelAddress = (320 * Y) + X mov ax, 320 ; Prepare for the multiplication mul [Y] ; Assuming that Y is defined in the data segment ; earlier in the program mov di, ax ; Put in into the pointer to the offset of ES add di, [X] ; Assuming that X is defined in the data segment ; earlier in the program mov al, [Color] ; Assuming that Color is defined in the data ; segment earlier in the program stosb ; Write it to the screen! See how easy that was? Something to remember is that it is zero-based. The upper-left corner is (0,0), and the lower-right is (319,199). A complete TASM Ideal mode procedure might look something like this (it assumes that the video card is already set to mode 13h): PROC WritePixel BASIC ; Or whatever language you might want to link ; it to USES es, di ; It's always a good idea to preserve ES and DI ARG X:word, Y:word, Color:BYTE mov di, 0a000h ; Put the video segment into DI mov es, di ; so it can easily be put into ES mov ax, 320 ; Prepare for the multiplication mul [Y] ; Offset pointer by the Y value passed in mov di, ax ; Put in into pointer to the offset of ES add di, [X] ; Offset the pointer by the X value passed in mov al, [Color] ; Put color to be written to the screen in AL stosb ; Write it to the screen! ret ENDP WritePixel To write a horizontal line, just put the length in CX, and replace the STOSB with a REP STOSB. Writing a vertical line is only a little more tricky. Observe the following TASM Ideal mode procedure: PROC VerticalLine BASIC ; Or whatever language you might want to link ; it to USES es, di ; It's always a good idea to preserve ES and ; DI ARG X:word, Y:word, Color:BYTE, Length:word mov di, 0a000h ; Put the video segment into DI mov es, di ; so it can easily be put into ES mov ax, 320 ; Prepare for the multiplication mul [Y] ; Offset the pointer by the Y value passed in mov di, ax ; Put in into the pointer to the offset of ES add di, [X] ; Offset the pointer by the X value passed in mov al, [Color] ; Put the color to be written to the screen ; in AL mov cx, [Length] ; Prepare for the loop YLoop: stosb ; Write it to the screen! add di, 319 ; Move down one row (DI has already advanced ; once because of the STOSB, thus the 319) loop YLoop ret ENDP VerticleLine Observe how there is a tight loop that moves DI down one row each iteration. In short, the easiest way to write directly to the Mode 13h video buffer is to think of the screen as just a 320 by 200 array of bytes, starting at A000:0000. Author: Michael Averbuch (mikeaver@prairienet.org) Last Change: 29 Dec 94 Return to the Table Of Contents------------------------------
Subject: 13. Protected Mode REVISED
13.1 PMODE Tutorials, FAQ, and other reference documentation Protected Mode Basics by Robert Collins http://www.x86.org/articles/pmbasics/tspec_a1_doc.html Excellent starting tutorial with source code. PMODE FAQ ftp://ftp.simtel.net/pub/simtelnet/msdos/asmutl/pmtut002.zip Protected Mode Book List http://www.interactive.net/~viren/Janz/Books/pmode_books.htm Jens Hohmuth PMODE Tutorial http://www.fh-zwickau.de/~hoh/pm_eng/text/index.htm HTML format pmode-l FAQ http://www.lysator.liu.se/~redhog 13.2 Source code Archives Walnut Creek PMODE Archives ftp://ftp.cdrom.com/pub/demos/code/hardware/pmode/index.html X2FTP.OULU.FI ftp://x2ftp.oulu.fi/pub/msdos/programming/pmode Protected mode utilities and some source code 13.3 PMODE Websites Cameron's 386+ Programming Page NOT CURRENTLY WORKING http://free.prohosting.com/~cameron/ 32 bit DOS extender/Utilities/pmode extender File formats and specifications/Game programming Knowledge Base with ASM tutorials, Denthor's VGA Trainer and Univ. of Guadalajara ASM tutorial Peter's PMODE Home Page http://www.geocities.com/SiliconValley/Peaks/1231/ PMODE tutorials and programming related files Niko Komin's Assembler for PCs page http://www.inx.de/~nkomin/html/assembe.htm Shareware, pmode, x86 mnemonics, ASM related links. http://www.alaska.net/~zumwalt Archives, Source Code, Technical Documentation, OS Chat Room and much more PASS-32, Dieter's Assembler http://www.eikon.e-technik.tu-muenchen.de/~et_514/pass32.html Debugger and DOS extender also available Dario Alpern's programs https://members.tripod.com/~alpertron/ENGLISH2.HTM PMODE examples 5.4 PMODE Mailing Lists Protected Mode Mailing list: To subscribe: Send: mailto:pmode-l-request@fys.ruu.nl subject: none body: subscribe pmode-l email@yourisp.name (Note that is pmode-l (ell) not pmode-1 (one) Use pmode-l@fys.ruu.nl to send email to others in the list. To unsubscribe: Send: mailto:pmode-l-request@fys.ruu.nl subject: none body: unsubscribe pmode-l email@yourisp.name Contributor: Raymond Moon, raymoon@moonware.dgsys.com Last changed: 19 Sep 98 Return to the Table Of Contents------------------------------
Subject: 14. Shareware ASM Libraries
14.1 ASMLIB PROGRAMMER'S TOOLKIT, VERSION 4.0 Douglas Herr's shareware assembly language library. This library is available from SimTel. ftp://ftp.simtel.net/pub/simtelnet/msdos/asmutl/asmlib40.zip The zip file contains only the medium model of the library. There are 405 assembly subroutines in a .lib file and documentation. Source code is available with registration and extra fee. The library covers the following areas: string/integer data manipulation screen mode subroutines text-mode multi-window subroutines disk & file subroutines text-mode video subroutines EMS and XMS subroutines floating-point subroutines graphics keyboard input subroutines mathematical solutions subroutines which determine PC status asmlib40 also comes with an editor, E16, written entirely with asmlib. Improvements since version 3.7 is auto-sizing of the near heap in the startup code. There have been some incremental improvements including 32k-color graphics and virtual graphics screens. 14.2 THE ASSEMBLY WIZARD'S LIBRARY, VERSION 2.1 This is Chris Walker's shareware assembly language library. This library used to be Thomas Hanlin's. ftp://ftp.simtel.net/pub/simtelnet/msdos/asmutl/asmwiz21.zip This library comes with documentation and one .lib file that supports small and tiny memory models. Source code is available with registration. The library covers the following areas: Base Conversions Mouse Services Exception Handling Sound and Music Delays and Countdowns String Services File Handling Telecommunications Filename Manipulation Time and Date Keyboard Services Video Services Long Integer Math Miscellaneous Services Memory Services 14.3 UCR Standard Library for Assembly Language Programmers This library is written by Randall Hyde and others. This library is available from many sites but most of them are seriously out of date. You can get the latest version at: http://webster.ucr.edu/Page_asm/RHUCRLib.html Unlike the previous libraries, there are no registrations fees and the included source code is released to the public domain. The author does request that if you use the library, you contribute at least one routine to the library. Standard Input Routines Character Set Routines Standard Output Routines Memory Management Routines Conversion Routines String Handling Routines Utility Routines 14.4 ALIB Version 3.0 ALIB is Jeff Ownens' shareware assembly language library. This library is available from SimTel. ftp://ftp.simtel.net/pub/simtelnet/msdos/asmutl/alib30.zip Like the UCR library described above, registration fees are not requested. The library consists of 179 assembly source files covering the following areas: compress - data compression and expansion config - program configuration, colors, paths, etc. compare - compare strings convert - hex/decimal/ascii conversions database - simple database functions disk - disk information, path changes, file searches display - fast display functions, write to display memory error - error handlers float - simple floating point math package math - dword math, crc, roots memory - memory manager, extended, xms, ems, conventional menu - menuing system message - messages in windows on screen misc - misc routines mouse/key - mouse and keyboard functions parse - extraction of parameters from command line random - random number generators search - search for character or string sort - sort buffer or file sound - sounds string - ascii string handling stdout - characters, strings, spaces to stdout system - system interrogation and setup time - time and date conversions 14.5 FREELIB, Version 3.0 Freelib v3.0 is a library of 200 routines that may be useful for assembly language programming. Freelib includes routines that do many of the tasks that make assembly language difficult - like buffered file I/O, formatted string output, memory allocation, etc. Also includes 16.16bit fixed point arithmetic, text screen output (EGA 80x25 or VGA 90x34), and VGA graphics in both 16 and 256 colors. All routines are highly optimized for size and speed, and average only 60 bytes each. Full source code and documentation is included for all routines. Freelib is public domain software, free for non-commercial use. The library is available from SimTel: ftp://ftp.simtel.net/pub/simtelnet/msdos/asmutl/freeli30.zip Contributor: Raymond Moon, raymoon@moonware.dgsys.com Last changed: 20 Dec 96 Return to the Table Of Contents