Classic Computer Magazine Archive COMPUTE! ISSUE 1 / FALL 1979 / PAGE 100


6502 Macro Assembler And Text Editor SYM Version $49.95

Carl W. Moser
3239 Linda Drive
Winston-Salem, North Carolina 27106

If you want to become serious about your business application or computer hobby, an assembler is a must. Many programs written in BASIC take too long to execute. I recently wrote a BASIC program which implemented a successive approximation analog-to-digital converter. Sample frequency was limited by the program to a few times per second. When the program was rewritten in machine language, the maximum sample rate increased 100 fold.

Only trivial programs should be hand-assembled. It takes too long and corrections are quite tedious. However, a good assembler at a reasonable price is hard to find. Carl Moser is offering a super assembler for the SYM (and PET, Apple and other 6502 machines). It has features normally found on much larger systems, e.g., macro capability. One line of source code in your program is expanded into many lines according to a previous definition. Assembly language programming should be facilitated once a library of macros is built up (much like FORTRAN subroutines).

I did have some trouble loading the original tape. I put the blame on SYM's 1.0 monitor and its notorious cassette problems. My back-up copy, made with the new 1.1 monitor on my system, works every time. The assembler/text editor requires memory from $2000-$3FFD. Default file boundaries for the SYM version are:

Text file: $200-$BFC

Label file: $C00-$EFC

Relocatable buffer: $F00

The system I am using (4K SYM, KIM-3(8K), and Seawell Little Buffered Motherboard) was able to run without changing the default boundaries.

In the week that I have had to test the program I have not exercised every feature of the assembler/text editor. However, every thing I have tried has worked! Some of my previous experience has been with assemblers written in BASIC and the difference in execution times for Moser's assembler (written in machine language and much faster) is absolutely phenomenal. I am not about to list all the features — you must look at the 50 page manual to appreciate the available commands for both the text editor and the assembler.

Even though I was very pleased with the package I have two minor "carping" points. One, the manual is written in a general manner with specifies for each version (PET, APPLE, and SYM) in appendices at the end. It is a little difficult for the SYM user (me) to find what he needs without a lot of paper shuffling. Two, the assembler requires you to specify zero page addressing modes with an asterisk. I would prefer that the assembler use this whenever possible with provision for a manual override. Once I forgot the asterisks in an early try at assembling. However, the text editor has a convenient "EDIT" command and I had no problem inserting the asterisks where needed. I like a forgiving program and I heartily recommend this package to serious SYM computer buffs.

Reviewed by Harvey B. Herman