I. Introduction

ASEM-51 is a two-pass macro assembler for the Intel MCS-51 family of microcontrollers.
It is running on the PC under MS-DOS, Windows and Linux.
The DOS real-mode assembler ASEM.EXE requires only 256 kB of free DOS memory and MS-DOS 3.0 (or higher).
The new protected-mode assembler ASEMX.EXE requires a 286 CPU (or better), and at least 512 kB of free XMS memory.
The new Win32 console-mode assembler ASEMW.EXE requires a 386 CPU (or better) and Windows 9x, NT, 2000 or XP.
The new Linux assembler asem requires a 386-based Linux system.
The new HTML documentation set requires a 90 MHz Pentium (or better) and a web browser.

The ASEM-51 assembly language is a rich subset of the Intel standard that guarantees maximum compatibility with existing 8051 assembler sources. ASEM-51 can generate two sorts of object files: Intel-HEX format, which is directly accepted by most EPROM programmers, and absolute OMF-51 format, which is required for many simulators, emulators and target debuggers. Thus ASEM-51 is suitable for small and medium MCS-51-based microcontroller projects in hobby, education and business. However, ASEM-51 has been designed to process also very large programs! Its most important features are:

• fast, compact, reliable, easy to use, and well-documented
• easy installation, almost no configuration required
• command line operation, batch and networking capability
• fully year 2000 compliant
• DOS (RM and PM), Win32 and Linux binaries available
• Intel-compatible syntax
• five location counters, one for each of the MCS-51 address spaces
• assembly-time evaluation of arithmetic and logical expressions
• segment type checking for instruction operands
• automatic code optimization of generic jumps and calls
• macro processing (that really works)
• nested include file processing
• nested conditional assembly
• absolute OMF-51 module output (with debug information)
• Intel-HEX file output
• hex-to-binary conversion utility
• built-in symbols for 8051 special function registers (can be disabled)
• direct support of more than seventy 8051 derivatives
• support of user-defined 8051 derivatives
• special support of the Philips 83C75x family
• 8051 register bank support
• detailed assembler listing with symbol table or cross reference
• further fancy printing facilities  
• documentation in ASCII and HTML format
• bootstrap program for testing on the MCS-51 target board
• support for easy integration into the popular Borland IDE
• limited update service by the author

The ASEM-51 software package has been developed with:

Borland-Pascal mit Objekten 7.0 © Borland International 1992
Delphi 2.0 Client/Server Suite © Borland International 1996
FreePascal 1.0.6 © Florian Klämpfl 2002