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From news.primenet.com!nntp.news.primenet.com!news.sprintlink.net!gryphon.phoenix.net!academ!binky.capnet.state.tx.us!goblin.tdh.state.tx.us!geraldo.cc.utexas.edu!cs.utexas.edu!math.ohio-state.edu!howland.reston.ans.net!swrinde!sgigate.sgi.com!news1.best.com!news.aimnet.com!ns2.mainstreet.net!sloth.swcp.com!news.dgsys.com!DGS.dgsys.com!raymoon Tue Apr 2 15:45:00 1996 Path: news.primenet.com!nntp.news.primenet.com!news.sprintlink.net!gryphon.phoenix.net!academ!binky.capnet.state.tx.us!goblin.tdh.state.tx.us!geraldo.cc.utexas.edu!cs.utexas.edu!math.ohio-state.edu!howland.reston.ans.net!swrinde!sgigate.sgi.com!news1.best.com!news.aimnet.com!ns2.mainstreet.net!sloth.swcp.com!news.dgsys.com!DGS.dgsys.com!raymoon From: raymoon@dgsys.com (Raymond Moon) Newsgroups: alt.lang.asm,comp.lang.asm.x86,news.answers,alt.answers,comp.answers Subject: x86 Assembly Language FAQ - General Part 2/3 Supersedes: <4gdskr$o9c@news.dgsys.com> Followup-To: alt.lang.asm,comp.lang.asm.x86 Date: 21 Mar 1996 22:50:08 GMT Organization: MoonWare Lines: 656 Approved: news-answers-request@MIT.EDU Distribution: world Expires: Sat, 20 Apr 1996 23:59:59 GMT Message-ID: <4ismf0$2tq@news.dgsys.com> Reply-To: raymoon@moonware.dgsys.com NNTP-Posting-Host: dgs.dgsys.com Summary: This is the FAQ for the x86 Assembly Language programmers for the alt.lang.asm and comp.lang.asm.x86 newsgroups. This particular section of the FAQ is part two of three parts that contain x86 assembly language information common to all assemblers. Keywords: x86 Assemby Language ASM FAQ General X-Newsreader: TIN [version 1.2 PL2] Xref: news.primenet.com alt.lang.asm:8421 comp.lang.asm.x86:18598 news.answers:66831 alt.answers:16273 comp.answers:17530 Archive-name: assembly-language/x86/general/part2 Posting-Frequency: monthly (21st of every month) Last-modified: 1996/03/19 ------------------------------ Subject: 15. How To Determine If A Pentium With The FDIV Problem Is Present The following is a short assembly language program that can detect the FDIV error: (It has been pointed out to me that the test against zero may lead to a false positive. On my 387, the result is exactly zero so that is why I coded it that way. PENERR has been tested on and identifies a Pentium with the FDIV error.) ================================================================= ; PENERR.ASM - Determines if Pentium FDIV error is present ; Version 1.00 ; Copyright 1994 - Raymond Moon ; This program is free for all to use. .286 .287 DGROUP GROUP _TEXT, _DATA _DATA SEGMENT PARA PUBLIC 'DATA' ; Data segment x dd 4195835 y dd 3145727 OK byte 'No Error$' ERR byte 'Pentium Error Present', 7, '$' _DATA ENDS _TEXT SEGMENT WORD PUBLIC 'CODE' ; Code segment assume cs:DGROUP, ds:DGROUP org 100h START: finit fld x fld st fld y ; 0 = y; 1 & 2 = x fdiv st(2), st ; 0 = y; 1 = x; 2 = x/y fmulp st(2), st ; 0 = x, 1 = (x/y)*y fsubp st(1), st ; 0 = (x/y)*y-x => should be zero fldz ; 0 = 0; 1 = (x/y)*y-x fcomp st(1) ; Is it zero fstsw ax ; get control word ffree st(1) ffree st sahf ; load flag register jz EQUAL ; If C3 not set, result = 0 lea dx, ERR ; DS:DX => ERR jmp OUTPUT EQUAL: lea dx, OK ; DS:DX => OK OUTPUT: mov ah, 9h ; Display string int 21h int 20h ; Terminate program _TEXT ends end START ================================================================= penerr.com in uuencode for those who do not want to assemble the above source code. ================================================================= begin 644 penerr.com MF]OCV09``=G`V09$`=SZWLK>Z=GNV-F;W^#=P=W`GG0&C191`>L$C19(`;0) MS2'-(````````````````````/L%0`#__R\`3F\@17)R;W(D4&5N=&EU;2!% .<G)O<B!0<F5S96YT!R1R ` end Contributor: Raymond Moon, raymoon@moonware.dgsys.com Last changed: 5 Jan 95 ------------------------------ Subject: 16. Accessing 4 Gigs of Memory in Real Mode Flat real mode is a popular name for a technique used to access up to 4 GB of memory, while remaining in real mode. This technique requires a 80386 or higher processor. The address space really is not flat, actually, this technique allows you treat one or more segments as large (32-bit) segments, thereby accessing memory above 1 MB. When the CPU accesses memory, the base address of the segment used is not described by the value currently in the appropriate register. The value is stored internally in a structure known as the descriptor cache. Changing the value of a segment register results in that segment's entry in the descriptor cache being recalculated according to the rules of the current mode. In real mode, the value of the segment register is shifted left four bits to find the base address of the segment, and the size of the segment is always 64k. In protected mode, the value in the segment register is used as an index into a descriptor table located in memory, and the base address and size (which may be as small as 4 KB, or as large as 4 GB)from the descriptor table are loaded into the descriptor cache. When the processor changes modes, the contents of the processor's internal descriptor cache are not changed. The reason is because changing them would result in (at the very least) the code segment being recalculated according to the new mode's rules, most likely causing your program to crash. Thus the program must load the segment registers with sensible values after the mode switch occurs. Consider an example where real mode code is located in segment 1000h. If switching modes caused an immediate recalculation of the descriptor cache, the processor would attempt to read entry 1000h of the descriptor table immediately upon switching to protected mode. Even if this were a valid descriptor (unlikely), it would have to have a base address identical to real mode segment 1000h (i.e., 10000h), and a size limit of 64 KB to prevent a probable crash. An invalid descriptor would cause an immediate processor exception. Normally, aside from preventing situations like that in the above example, there is little to be said about this feature. After all, as soon as you reload new values into the segment register, the descriptor cache entry for that segment will be reset according to the rules of the current mode. After switching from protected mode to real mode, however, when you load the segment registers with their new values, the segment's base address is recalculated according to real mode rules, but the size limit is not changed. After setting the 4 GB limit (which must be done in protected mode), it will stay in place until changed by another protected mode program, regardless of what values are loaded in the segment register in real mode. So, the steps to using this technique are as follows: 1. Set up a bare bones global descriptor table, with a null entry, and a single entry for a 4 GB segment. The base address of this segment is not important. 2. If you don't wish to define an interrupt descriptor table (IDT), you must disable interrupts before switching to protected mode. You do not need a full-fledged protected mode environment for this, so it is easiest just to disable interrupts and not worry about the IDT. 3. Switch to protected mode. 4. Load the segment registers you wish to change with the selector for the 4 GB segment. I recommend using FS and/or GS for this purpose, for reasons I'll describe below. 5. Return to real mode. 6. Re-enable interrupts. After these steps, you can then load your segment registers with any value you wish. Keep in mind that the base address will be calculated according to real mode rules. Loading a value of 0 into a segment register will result in a 4 GB segment beginning at physical address 0. You can use any of the usual 32-bit registers to generate offsets into this segment. Some points to keep in mind: 1. Some software depends on 64 KB segment wrap-around. While rare, it is possible that you will encounter software that crashes if the older segments (DS or ES) are 4 GB in size. For that reason, I recommend only using FS and/or GS for this purpose, as they are not used as widely as the others. 2. You should never change the limit of the code segment. The processor uses IP (not EIP) to generate offsets into the code segment in real mode; any code beyond the 64 KB mark would be inaccessible, regardless of the segment size. 3. You should never change the limit of the stack segment. This is similar to the above; the processor uses SP in real mode, rather than esp. 4. Because of the necessity of switching to protected mode, this technique will not work in a virtual 8086 mode "DOS box" from Windows, OS/2, or any other protected mode environment. It only works when you start from plain, real mode DOS. Many memory managers also run DOS in V86 mode, and prevent the switch to protected mode. It is possible to use VCPI to work around this, but if you go to that length you will probably find that you have implemented a complete protected mode environment, and would not need to return to real mode anyway. 5. This technique will not work in the presence of any protected mode software that changes segment size limits. When that software returns control to your real mode program, the limits will be the values to which the protected mode code set them. If these limits are different that what your program used, problems can result. At the very least, your program will return incorrect results when accessing data stored in extended memory. At worst, your program will crash and burn. The benefits of this technique are many. Most importantly, you can access extended memory without resorting to slow BIOS calls or having to implement a complete DOS extender. If your program uses interrupts extensively (timer interrupts for animation or sound, for example), real mode is a better choice because protected mode handles interrupts slower. DOS itself uses this technique in HIMEM.SYS as a fast, practical method of providing access to extended memory. Code demonstrating this technique is available in the file, realmem.zip. This file is available using anonymous ftp from x2ftp.oulu.fi in the directory, pub/msdos/programming/memory. For further reading on this topic, I suggest "DOS Internals," by Geoff Chappell. It is published by Addison-Wesley as part of the Andrew Schulman Programming Series. The ISBN number is 0-201-60835-9. Contributor: Sherm Pendley, grinch@access.mountain.net Last changed: 15 Jan 95 ------------------------------ Subject: 17. What Is Available at ftp.intel.com To obtain a description of the files available at Intel: ftp://ftp.intel.com/pub/IAL get libdir.txt Most of the files are press releases, but there are some hidden jewels. Search for and read the files under the Intel386, Intel486 and Pentium subdirectories. Here are a sample of files that may be of interest (path from IAL subdirectory is given): Pentium/opt32.doc - Optimizations for Intel's 32-bit processors in MS Word format. Pentium/pairng.txt - Instruction pairing optimization for Pentium processor - text format. Pentium/p5cpui.txt - new official CPU identification scheme - text format. Pentium/p5masm.mac - MASM macros for instructions new with Pentium Tools_Utils_Demos/prot.txt - MASM code for entering protected mode - text format. Intel486/2asm10.zip - C source for 8086-80486 16/32 bit disassembler - pkzip format. Contributor: Raymond Moon, raymoon@moonware.dgsys.com Last changed: 8 Jan 95 ------------------------------ Subject: 18. Interrupts and Exceptions "(with interrupts) the processor doesn't waste its time looking for work - when there is something to be done, the work comes looking for the processor." - Peter Norton INTERRUPTS AND EXCEPTIONS Interrupts and exceptions both alter the program flow. The difference between the two is that interrupts are used to handle external events (serial ports, keyboard ) and exceptions are used to handle instruction faults, (division by zero, undefined opcode). Interrupts are handled by the processor after finishing the current instruction. If it finds a signal on its interrupt pin, it will look up the address of the interrupt handler in the interrupt table and pass that routine control. After returning from the interrupt handler routine it will resume program execution at the instruction after the interrupted instruction. Exceptions on the other hand are divided into three kinds. These are Faults, Traps and Aborts. Faults are detected and serviced by the processor before the faulting instructions. Traps are serviced after the instruction causing the trap. User defined interrupts goes into this category and can be said to be traps, this includes the MS-DOS INT 21h software interrupt for example. Aborts are used only to signal severe system problems, when operation is no longer possible. See the below table for information on interrupt assignments in the Intel 386, 486 SX/DX processors, and the Pentium processor. Type specifies the type of exception. --------------------------------------------------------------------- Vector number Description --------------------------------------------------------------------- 0 Divide Error (Division by zero) 1 Debug Interrupt (Single step) 2 NMI Interrupt 3 Breakpoint 4 Interrupt on overflow 5 BOUND range exceeded 6 Invalid Opcode 7 Device not available (1) 8 Double fault 9 Not used in DX models and Pentium (2) 10 Invalid TSS 11 Segment not present 12 Stack exception 13 General protection fault 14 Page fault 15 Reserved 16 Floating point exception (3) 17 Alignment check (4) 18 - 31 Reserved on 3/486, See (5) for Pentium 32 - 255 Maskable, user defined interrupts --------------------------------------------------------------------- (1) Exception 7 is used to signal that a floating point processor is not present in the SX model. Exception 7 is used for programs and OSes that have floating point emulation. Also the DX chips can be set to trap floating point instructions by setting bit 2 of CR0. (2) Exception 9 is Reserved in the DX models and the Pentium, and is only used in the 3/486 SX models to signal Coprocessor segment overrun. This will cause an Abort type exception on the SX. (3) In the SX models this exception is called 'Coprocessor error'. (4) Alignment check is only defined in 486 and Pentiums. Reserved on any other Intel processor. (5) For Pentiums Exception 18 is used to signal what is called an 'Machine check exception'. The other interrupts, (32-255) are user defined. They differ in use from one OS to another. For a list of MS-DOS interrupts, see 'Obtaining HELPPC' (Subject #6) or Ralf Browns Interrupt List (Subject #11) Contributor: Patrik Ohman, patrik@astrakan.hgs.se Last changed: 10 Jan 95 ------------------------------ Subject: 19. ASM Books Available The format is Author, Title, Level, and short description Ray Duncan Advanced MSDOS Programming Advanced Both a tutorial and a reference for MS-DOS capabilities and services, including reference sections on DOS function calls, IBM ROM BIOS, mouse driver and LAM. expanded memory. Excellent quality example programs throughout. By Peter Norton and John Socha Peter Norton's Assembly Language Book For the IBM PC Novice Good for an introduction to Assembly Language. Plenty of programming examples. Older versions of this book used to have a sample disk. And as you read the book, you slowly add on code to what eventually is Disk Patch - the book's version of Norton's commercially Disk Edit. Great for complete beginners seeking novice rank. ***** WARNING -- Next two books may come with virus infected disk. Use your anti-virus software to check and clean, if necessary, these diskettes! Maljugin, Izrailevich, Sopin, and Lavin The Revolutionary Guide to Assembly Language Novice This is one of the best introductory texts I've ever seen There are so many authors since the topic is broken down into specific categories: video, BIOS, keyboard, etc.. Most intro texts force you to follow a set plan of learning assembly, but in this book you can turn to a specific topic almost immediately. It's so-so as a reference book, however - a few tables of interrupts in the back. Maljugin, Izrailevich, Sopin, and Lavin Master Class Assembly Language Advanced Review: This is the sequel to The Revolutionary Guide To Assembly Language. Equally thick and massive, it covers many of the topics we see today - hardware interfaces, sound cards, data compression, even protected mode programming. Brief review of assembly at the beginning, but moves very quickly. Read this if you're intermediate seeking expert status. Definitely not recommended for beginners. If you are a beginner and you think you like the topics covered in this book, buy the one before it too. Also comes with a disk of source code examples from the book (MASM highly recommended, not TASM). ***** End of Possible Virus Alert Alan Wyatt Advanced Assembly Language Advanced This book's best feature is it comprehensive guide on device drivers. There are good chapters on controlling the mouse, file access, using memory, etc. Ralf Brown and Jim Kyle PC Interrupts - 2nd Edition Intermediate/Advanced The definitive book on interrupt programming for PC's and compatibles. Based on the freeware Interrupt List by Ralf Brown For an extensive book list without descriptions, point your web browser to http://alaska.net/~rrose/assembly.htm Sites with more books but no reviews are: http://www.fys.ruu.nl/~faber/Amain.html http://www.poweramp.net/~jvahn Contributors: Antonio Alonso, Solomon Chang, Paul Gilbert, Dave Navarro, Mike Schmit and James Vahn. Last changed: 19 Dec 95 ------------------------------ Subject: 20. ASM Code Available On The Internet 20.1 SIMTEL SITES The SimTel has a directory devoted to assembly language. ftp://ftp.coast.net/SimTel/msdos/asmutil or http://simtel.coast.net/SimTel/ 20.2 80xxx Snippets Fidonet's echo for 80xxx programming has a collection of code that is maintained by Jim Vahn, jvahn@short.circuit.com. The collection is available via mail based archive server or Fidonet file requests to 1:346/15. To get a list of files available via e-mail, send an empty message to files@circuit.com. The server will return a list of all files available and instruction on how to retrieve them. The assembly language snippets dated before Mar 93 are available in one zip file at the above SimTel sites under the filename 80XXX393.ZIP. The Snippets are now on the web. In addition to downloading the snippets there is an assembly language related book list. The URL is: http://www.poweramp.net/~jvahn/ 20.3 X2FTP.OULU.FI This ftp site, x2ftp.oulu.fi, has some asm source code not available at the SIMTEL sites. The following describes some directories and the type of information that is available in them. /pub/msdos/programming/pmode - protected mode utilities and some source code. /pub/msdos/programming/source - some asm code /pub/msdos/programming/prgsrc - some asm code 20.4 FTP.X86.ORG This ftp site contains much of the code and information available from Robert Collins' web site. ftp://ftp.x86.org/x86 20.5 OMEN.COM Omen has assembly language source available from its web site. The address is: http://www.omen.com.au/Files/asm.html Much of the code is archived in the .arj format. You will need the appropriate. One is available: ftp://ftp.coast.net/SimTel/msdos/archiver/arj242b.exe 20.6 JUMBO JUMBO is the Official Web Shareware Site. It has a directory devoted to assembly language source code, libraries and utilities: http://www.jumbo.com/prog/dos/asmutil 20.7 THE REEF This FTP site has source code and information that I have not found else where. Unfortunately, many of the files are compressed using arj and lzh. ftp://futute.dreamscape.com/pub/thereef/asm 20.8 PC GAMES PROGRAMMER ENCYCLOPEDIA This encyclopedia is a collection of files related to game programming. Many of these files contain programming examples. Topics included are ASM tutorial, VGA and SVGA programming information, graphic algorithms, graphic file formats, soundcard and other PC hardware programming information. This file is available from: ftp://teeri.oulu.fi/pub/msdos/programming/gpe/pcgpe10.zip Contributor: Raymond Moon, raymoon@moonware.dgsys.com Last changed: 8 Jan 96 ------------------------------ Subject: 21. How To Commit A File The easiest solution is to open or create the file to be committed using Int 21h function 6ch, extended open/create. The BX register contains the desired Open Mode. One option that can be or'ed into this register is what Microsoft calls, OPEN_FLAGS_COMMIT, that has the value of 4000h. Using this option caused DOS to commit the file after each write. This function has been available (documented) since DOS 4.0. If you do not want to commit the file at each write but only when certain conditions are met, use Int 21h function 68h, commit file. The functions has been available (documented) since DOS 3.3. If you need to support versions of DOS before 3.3, the following technique will flush the all stored data without closing and opening the file. It is the opening of the file that is time consuming. 1. Use 21h function 45h to create a duplicate file handle to the file to be flushed. 2. Close that duplicate file handle. This technique will work all the way back to DOS 2.0. Contributor: Raymond Moon, raymoon@moonware.dgsys.com Last changed: 30 Jan 95 ------------------------------ Subject: 22. Using Extended Memory Manager 22.1 HOW TO USE XMS XMS usage - short recipe: 1. Verify have at least 286 (pushf; pop AX; test AX,AX; js error). 2. Verify vector 2Fh set (DOS 3+ sets it during boot). 3. AX=4300h, int 2Fh, verify AL=80h (means XMS installed). 4. AX=4310h, int 2Fh, save ES:BX as dword XmsDriverAddr. 5. AH=8, call [XmsDriverAddr] - returns ax=largest free XMS memory block size in kB (0 if error). 6. AH=9, DX=required size in kB, call [XmsDriverAddr] - allocates memory (returns handle in DX - save it). 7. AH=0Bh, DS:SI->structure { dword size (in bytes and must be even), word source_handle, dword source_offset, word destination_handle, dword destination_offset } (if any handle is 0, the "offset" is Real Mode segment:offset) 8. AH=0Fh, BX=new size in kB, DX=handle, call [XmsDriverAddr] - changes memory block size (without losing previous data). 9. AH=0Ah, DX=handle, call [XmsDriverAddr] - free handle and memory. Initially, should process #1-#6, then can use #7 to put data in/get data from XMS memory, or #8 to change XMS memory block size. On exit use #9 to free allocated memory and handle. Hint: handle cannot be 0, since zero is used as "no handle allocated" value. Errors for XMS calls (except AH=7 - Query A20) are signaled by AX=0. Error code returned in BL, few codes can check for are: 80h - not implemented, 81h - VDISK detected (and it leaves no memory for XMS), 82h - A20 error (e.g. fail to enable address line A20), A0h - all allocated, A1h - all handles used, A2h - invalid handle, A3h/A4h - bad source handle/offset, A5h/A6h - bad destination handle/offset, A7h - bad length, A8h - overlap (of source and destination areas on copy), A9h - parity error (hardware error in memory), ABh - block is locked, 00h - OK For more info read INT 2Fh, AH=43h in Ralf Brown interrupt list. 22.2 WHAT IS THE 'LINEAR BLOCK ADDRESS' RETURNED BY LOCK MEM BLOCK? When you lock mem block, XMS driver arranges memory governed by it in a way the locked block forms one contiguous area in linear address space and returns you starting address of the memory. Linear address is base address of segment + offset in segment, in Real Mode it is segment*16+offset, in Protected Mode the base address is kept in LDT or GDT; note offset can be 32-bit on 386+. If paging isn't enabled, linear address = physical address. You don't need the linear address unless you use 32-bit offsets in Real Mode or you use Protected Mode (see previous answer for explanation how you can access XMS memory). Contributor: Jerzy Tarasiuk, JT@zfja-gate.fuw.edu.pl Last Changed: 30 Jan 95 ------------------------------ Subject: 24. EXE2BIN Replacement A utility, EXE2BIN, used to be included in DOS. This utility was needed to convert the output of the linker from .EXE to .com format because the linkers could not do this directly. As linkers became more capable, the need for this utility vanished, so EXE2BIN was dropped from DOS. If you still are using an older assembler and linker, you now have been left out in the cold. Well, not quite, as there are three shareware equivalent programs. 23.1 EXECOM14.ZIP EXECOM was written by Chris Dunford in C. The .zip file contains the executable, documentation and the .c source that Chris Dunford has released into the public domain. The current version is 1.04 with a 2 Mar 88 date. 23.2 BIN.ZIP This replacement version was written by Bob Tevithick. It is based upon versions 1.00 of Chris Dunford's program. The .zip file contains only the executable and documentation. No source is included. 23.3 X2B11.ZIP X2B is written in 100% assembly language by Henry Nettles. Again it is based upon Chris Dunford's program. The zip file contains the executable and .asm source. The documentation is in the source code. 23.4 AVAILABILITY All there .zip files are available at any SimTel Mirror site. They are found in the SimTel/msdos/asmutil directory. 23.5 THE REAL THING, EXE2BIN.EXE If you need the real thing, EXE2BIN.EXE is available on the DOS Supplemental Diskettes. This disks can be downloaded from microsoft. ftp://ftp.microsoft.com/peropsys/msdos/public/supplmnt DOS62SP.EXE for MS DOS 6.2 DOS6SUPP.EXE for MS DOS 6.0 SUP621.EXE for MS DOS 6.21 SUP622.EXE for MS DOS 6.22 Contributor: Raymond Moon, raymoon@moonware.dgsys.com Last changed: 8 Jan 96 ------------------------------ Subject: 24. ASM Tutorials Available There are several assembly language tutorials available on the internet. 24.1 FROM SIMTEL MIRRORS From the SimTel Mirrors, e.g., oak.oakland.edu, there are two tutorials available in the simtel/msdos/asmutil directory. asmtutor.zip The tutorial is by Joshua Averbach. It is old as it is dated in Jun 1988. It is designed for the 8088 processor. primer2.zip This tutorial is designed specifically for the cheap assembler (CHASM) also available in this directory. 24.2 GAVIN ESTEY'S TUTORIAL A new tutorial has been written by Gavin Estey. He has provided his tutorial in ascii text and in Microsoft Word format. They are available using anonymous ftp from: ftp://x2ftp.oulu.fi/pub/msdos/programming/docs get asmtutx.zip For ascii text get asmtutwp.zip For MS Word document 24.3 VLA's Assembly Language Tutorial This tutorial is available directly or as part of the PC Games Encyclopedia. This file is available from: http://www.mds.mdh.se/~dat94avi/asmvla.zip or as part of the PC Games Encyclopedia: ftp://teeri.oulu.fi/pub/msdos/programming/gpe/pcgpe10.zip 24.4 ASM Tutorial on University of Guadalajara Web Site The on-line tutorial descibed below also is available as an ascii text. http://udqftp.cencar.mx/ingles/tutor/assem.zip 24.5 Web Sites Assembly Language Tutorials http://udgftp.cencar.udg.mx/ingles/tutor/Assembler.html ASM Tutorial on University of Guadalajara Web Site http://www.cit.ac.nz/smac/csware.htm Version 2.6 of on-line 386 assembly languager course. Self tests, assignments, course notes, and software are included. http://www.feldspar.com/~mbabcock/Programming/asmtut1.htm Mike Babcock's ASM Tutorial http://www.mds.mdh.se/~dat94avi/demoschool.htm Tutorial emphasises video and gaming techniques and C and assembly interface. Contributor: Raymond Moon, raymoon@moonware.dgsys.com Last changed: 17 Feb 96