MCA.EXE - assembler for 8748 and 8749 microcomputers


mca.exe - executable program for MS-DOS

mca.txt - description of the program with instruction set definitions (required for use of the program)

mca1.asm - short sample program

mca2.asm - longer sample program


The mca.exe program is an assembler for the Intel 8748 and 8749 microcomputers. The program runs in MS-DOS, but I intend to compile the program for Windows if and when DOS program support is no longer readily available. The program is run by entering "mca filename" on the DOS command line. If the filename does not include a file extension, the ".asm" extension is automatically appended.

The program generates a work file ".wrk", an error file ".err" and an object code file ".obj" which is written in Intel Hex format. These files are generated each time the program is executed. The 8749 instruction set definitions are contained in the file "mca.txt" and must be loaded each time the program is run. Therefore, mca.txt needs to be located in the same directory as mca.exe.

Assembler directives

org XXX
neworg XXX

These two directives advance the address counter to the location XXX (filing the addresses passed with NOP instructions (0x00). Multiple org and new org statements can be used in the same program. These are useful to avoid conditional jumps across page boundaries or to place look-up tables in specific locations.

constant label XX

Gives label the value XX

include filename

Opens filename and begins compiling from this file. Very useful for often used subroutines and look-up tables. The mca.exe program does not support nesting of include files (i.e include files having include files of their own).

Source code format

Constants and labels must be three to eight characters in length. Comments must begin with a semi-colon ";". Look-up tables may be generated by placing a single byte value at the beginning of a series of lines. The program only recognizes numbers in hex format (i.e. 0x00 to 0xffff). It is suggested that source code files be created with "edit", the DOS editor, with tabs set to five spaces. For compatibility with other assemblers, use of constants may be preceded by an immediate indicator "#".

License grant

The mca.exe program in object code and documentation are distributed as freeware. This means you may use and modify the materials for your own personal use. Additionally, you may freely distribute the materials to others (and are encouraged to do so) provided no fee is charged for the materials and the materials are not modified in any way. All rights not specifically granted herein are reserved.

If you like the program, you may become a registered user by sending your email address and $20 to:

John Wolfe
82 Idora Avenue
San Francisco, CA 94127

A registered user will receive email notification of the availability of future updates of the program as well as a copy of the program source code (written in C) which the user may use and modify for the user's own personal use. Questions and comments and any bug reports on the program should be directed to

Other Suggested Assembler Links


mca.exe v2.0 11.22.99