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 - Borland TASM
Supersedes: <5jgm0a$ijs@news.dgsys.com>
Followup-To: alt.lang.asm,comp.lang.asm.x86
Date: 22 May 1997 00:26:03 GMT
Organization: MoonWare
Lines: 346
Approved: news-answers-request@MIT.EDU
Distribution: world
Expires: Fri, 20 Jun 1997 23:59:59 GMT
Message-ID: <5m03qr$fof@news.dgsys.com>
Reply-To: raymoon@moonware.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 contains x86 assembly information specific to the Borland TASM assembler.
Keywords: x86 Assemby Language ASM FAQ Borland TASM
Archive-Name: assembly-language/x86/borland
Posting-Frequency: monthly (21st of every month)
Last-modified: 1997/05/21
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Subject: 1. Introduction and Intent
This is the x86 Assembly Language FAQ for the comp.lang.asm.x86 and alt.lang.asm newsgroups. This FAQ is posted monthly on or about the 21st of the month on both newsgroups and news.answers, alt.answers and comp.answers. It also is archived at the normal FAQ archival sites and the SimTel mirror sites in the msdos/info directory. Lastly, the current version is available from my web page as: As text files: http://www2.dgsys.com/~raymoon/faq/asmfaq.zip As html documents: http://www2.dgsys.com/~raymoon/faq/asmfaqh.zip Currently, this FAQ is broken into six sections. The following are the section filenames and the scope of each section of the FAQ. assembly-language/x86/general/part1 - This is the basic portion of the FAQ that contains information of interest to all assembly language programmers. In general, the information contained in this portion of the FAQ is not specific to any particular assembler. assembly-language/x86/general/part2 - This is a continuation of the above FAQ. assembly-language/x86/general/part3 - This is a continuation of the above FAQ. assembly-language/x86/microsoft - This portion of the FAQ contains information specific for the Microsoft MASM. assembly-language/x86/borland - This portion of the FAQ contains information specific for the Borland TASM. assembly-language/x86/a86 - This portion of the FAQ contains information specific for the Shareware A86 Assembler and D86 Debugger. The scope and content of this FAQ is to go beyond just answering the frequently asked questions. I am including pointers to assembly language treasure troves that are hidden out on the internet. I believe that this will enhance the FAQ's value not only to the novices but also to the old hands. For the ease of determining what has changed since the last FAQ, the Table of Contents will have "REVISED" at the end of the subject line for all revised subjects. If more than one FAQ revision has been missed, the "Last Changed:" entry at the end of each subject can be used to determine which subjects have been revised during the intervening time frame. The information in this FAQ is free for all to use as long as you acknowledge the source. This FAQ can be reproduced in part or in its entirety as long as the copyright is included. This FAQ can be made available on public servers, like ftp, gopher or WWW servers. Please do not modify the file, such as converting it into some other format, without prior permission of the author. All references to files and locations are in Uniform Resource Locators (URLs) format. Some web browser will be able to use these URLs directly as hot links. If the format is not clear to you, get RFC 1738. It is available from: ftp://ds.internic.net/rfc/rfc1738.txt Suggestions for changes and comments are always welcome. They can be posted to either newsgroup or e-mailed directly to the me. Author: Raymond Moon, raymoon@moonware.dgsys.com Copyright 1997 - Raymond Moon ALL RIGHTS RESERVED Last Changed: 6 Jan 97 Return to the Table Of Contents
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1. Introduction And Intent 2. Table Of Contents REVISED 3. TASM Ideal Mode 4. Borland TASM Information 5. Borland tools/Windows 95 Interworking Patches Available 6. FREELIB, Version 3.0 7. TASM Source Code Available on the Internet REVISED [General][MASM][TASM][A86/D86]
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3.1 SUMMARY TASM, Borland's assembler, supports an alternative to MASM emulation. This is known as Ideal mode and provides several advantages over MASM. The key (questionable) disadvantage, of course, is that MASM style assemblers cannot assemble Ideal mode programs. 3.2 MEMORY CONTENTS Square brackets are used consistently to refer to memory contents. Notice that size qualifiers are not necessary when TASM has enough information by context to figure out the data size involved. Here are some examples without segment details: ByteVal db ? ; "ByteVal" is name of byte variable mov ax, bx ; OK: Move value of BX to AX mov ax, [bx] ; OK: Move word at address BX to AX. Size of ; destination is used to generate proper object ; code mov ax, [word bx] ; OK: Same as above with unnecessary size ; qualifier mov ax, [word ptr bx] ; OK: Same as above with unnecessary size ; qualifier and redundant pointer prefix mov al, [bx] ; OK: Move byte at address BX to AL. Size of ; destination is used to generate proper object ; code mov [bx], al ; OK: Move AL to location BX mov ByteVal, al ; Warning: "ByteVal" needs brackets mov [ByteVal], al ; OK: Move AL to memory location named "ByteVal" mov [ByteVal], ax ; Error: unmatched operands mov al, [bx + 2] ; OK: Move byte from memory location BX + 2 to ; AL mov al, bx[2] ; Error: indexes must occur with "+" as above mov bx, Offset ByteVal ; OK: Offset statement does not use brackets mov bx, Offset [ByteVal] ; Error: offset cannot be taken of the contents ; of memory lea bx, [ByteVal] ; OK: Load effective address of "ByteVal" lea bx, ByteVal ; Error: brackets required mov ax, 01234h ; OK: Move constant word to AX mov [bx], 012h ; Warning: size qualifier needed to determine ; whether to populate byte or word mov [byte bx], 012h ; OK: constant 012h is moved to byte at address ; BX mov [word bx], 012h ; OK: constant 012h is moved to word at address ; BX STRUCTURE REFERENCES Ideal mode handles structured records beautifully. When referring to structure members the dot operator is used. The name to the left of the dot is always the address of a structure and the name to right is always a structure member. Ideal mode permits member names to be duplicated in different structures. Here is a simple example, again without segment details: Struc PosType Row dw ? Col dw ? Ends PosType Union PosValType Pos PosType ? Val dd ? Ends PosValType Point PosValType ? mov [Point.Pos.Row], bx ; OK: Move BX to Row component of Point mov [Point.Pos.Row], bl ; Error: mismatched operands INDIRECTION Ideal mode enforces type-size checking even with indirected references. Using the above structure, here is how indirection is handled. BX is assumed to point to an instance of PosValType in memory. Indirection is used frequently when pointers are passed to procedures. mov [(PosValType bx).Pos.Row], ax ; OK: Move AX to Row component of PosValType instance ; pointed to by BX mov [bx + PosValType.Pos.Row], ax ; OK: same as above mov [bx + PosValType.Pos.Row], al ; Error: mismatched operands SEGMENT GROUPS The Offset operator always evaluates the offset of a data instance relative to its group, not its segment. This allows Offset to be used without qualifying each reference with the appropriate group name. Labels in a segment could be used to determine segment offsets if needed. RESOURCES Books and files which will be of interest to programmers wishing to know more about the Ideal mode of Borland's TASM assembler include the following: Turbo Assembler User's Guide / Borland International. ------------------------------------------------------------------ Naturally, this is the definitive text on Ideal mode. Its focus is strictly on using TASM; it does not cover assembly language or the x86 instruction set. Exasperatingly, the examples in the book all use MASM emulation mode, and only one of the four complete program examples included with TASM (at least version 3.1) uses Ideal mode. The example that does use Ideal mode is a very flexible WHEREIS program. Studying this 13 file example should be sufficient for anyone wishing to understand Ideal mode. Mastering Turbo Assembler / Tom Swan. Indianapolis, IN: Hayden Books, c 1989. ----------------------------------------------------------------------- This book is not just another Microsoft Assembler book reprinted with a Turbo Assembler cover. Swan uses and promotes Ideal mode throughout. This is a great beginning text for programmers who are still hassling with the ubiquitous non-reentrant interrupt handler known as DOS. It includes an overview of the x86 instruction set. SKEL32.ZIP / Bill Magaletta. Obtainable by ftp at hobbes.nmsu.edu:/os2/32bit/program as well as ftp-os2.cdrom.com and CompuServe ----------------------------------------------------------------------- This is a standalone 32 bit OS/2 Ideal mode program, the simplicity of which will make converts of DOS programmers dealing with interrupts and segments. It includes an overview of the initial register states of DOS and OS/2 programs. This example illustrates the fact that TASM for DOS can be used to produce object files for OS/2. Contributor: Kurt Jung, kwjung@vela.acs.oakland.edu Last changed: 17 Jan 95 Return to the Table Of Contents
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Subject: 4. Borland TASM Information
4.1 Borland FTP Site Borland maintains a ftp site which has a directory dedicated to TASM. Most entries are patches and HOW-TOs, but there is a shell for TSRs that will load and unload either high or low. ftp://ftp.borland.com/pub/techinfo/techdocs/language/tools/turboasm 4.2 Borland Web Site At Borland's Web Site, I only could find product and ordering information on TASM. The only reference to technical information was a pointer to Borland's ftp site. Contributor: Ray Moon, raymoon@moonware.dgsys.com Last changed: 11 Nov 95 Return to the Table Of Contents
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Subject: 5. Borland tools/Windows 95 Interworking Patches Available
5.1 TASM32/H2ASM/H2ASM32 FAIL UNDER WINDOWS95 Using the 32bit tools from Borland C++ 4.5 / TASM 4.0 under Windows 95 can fail when the DOS based tools tools are called from the Windows IDE. The nature of the problem is that any attempt to specify a commands file using the @ style argument will fail due to an incompatability between Windows 95 long filenames, and the TASM32.EXE file-open code. Note that by default the Borland C++ 4.5 IDE uses the @ directive for launching TASM32.EXE if 32bit instructions (which are not handled by the inline C++ assembler) are encountered in a user's source. Although the Borland tools reportedly use the PowerPack DPMI extensions for their 32bit operation, user applications which use the Powerpack libraries do not seem to be affected by this problem. A patch is available to correct this issue from location: ftp://ftp.borland.com/pub/techinfo/techdocs/language/tools/turboasm/ta4p01.zip This should be applied using the patcher executable from location: ftp://ftp.borland.com/pub/techinfo/techdocs/language/cpp/bcpp/patch/patch.zip Contributor: Iain Barker, ibarker@bnr.ca Last changed: 19 Feb 96 Return to the Table Of Contents
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Subject: 6. 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
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Subject: 7. TASM Source Code Available on the Internet
8.1 TENIE REMMEL'S ASSEMBLY SNIPPETS CODE COLLECTION The Assembly Snippets is a large collection of assembly language code and other information. Many files from the original 80XXX snippets, the ASM0-Z collection, and the Aquila site are included. All code is 99% guaranteed to compile under TASM. This new release contains the following items, among others: An object file disassembler A 4971 byte Tetris game Several Conway LIFE programs Assembly & Disassembly tables A demonstration of FakeMode Several powerful editors A complete DOS extender A Pentium optimization list A ModeX graphics library Info for writing antivirus You can download these rather large files from SimTel: ftp://ftp.simtel.net/pub/simtelnet/msdos/asmutl/asnip40a.zip 1.41 Megs ftp://ftp.simtel.net/pub/simtelnet/msdos/asmutl/asnip40b.zip 1.35 Megs ftp://ftp.simtel.net/pub/simtelnet/msdos/asmutl/asnip40c.zip 1.32 Megs Contributor: Raymond Moon, raymoon@moonware.dgsys.com Last changed: 21 MaY 97 Return to the Table Of Contents