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
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Followup-To: alt.lang.asm,comp.lang.asm.x86
Date: 22 May 1997 00:26:03 GMT
Organization: MoonWare
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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
------------------------------
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------------------------------
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]
------------------------------
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------------------------------
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------------------------------
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
------------------------------
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------------------------------
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