[author : Kenneth Young] #Audio #Graphics #Event #Overview

Extract : «  Dear Dr. Dobb’s,

Enclosed is a copy of a letter I recently sent Bill Fuller and Neil Ferguson of the Computer Hobbyist Group of North Texas. It is about some of the new personal computing products I saw at the Mini/Micro show and my preliminary evaluation of them. I also sent a similar letter to Sol Libes and Russell Gorr of the Amateur Computer Group of New Jersey. I’ve been particularly impressed with the work these people have been doing. They really do sincerely care about computer hobbyists. That’s why I wrote them and also the reason why I am writing you now. If you feel my letter to be of sufficient general interest to fellow computer enthusiasts, please feel free to use it in your publication. [...]  »

[author : Paul R. Poduska, Ph.D.] #Computer #Review

Extract : «  Editorial Note: If nothing else, the Heath H-8 system is certainly sparking a great deal of comment. To those who may have missed it, we refer to the “H-8: Pro & Con” article in Dr. Dobb’s no. 19. Here now is another offering from a user who seems quite pleased with the system-TRW

Microcomputers—that is to say, microprocessor-based computers—have, over the past several years, evolved into several rather distinct species: the single-board small system, the mother-board-based medium size system, and the full mainframe system. Within this last group, buyers can find several different styles or mainframe configurations. Some models have elaborate front panels with rows of toggle switches and LED indicators, others have no front panel devices at all, while still a third group incorporates numeric keypads and seven-segment LED displays.

None of the main-frame types is a priori better than the other. Each system has its own assets depending upon the kinds of uses to which it will be put. And, in this regard, the Heathkit H-8 eight-bit microcomputer might be viewed as a truly general purpose system. [...]  »

[author : Theodore E. Bridge] #Listing #Assembly #Programming

Extract : «  [...] My first job was to get “A 6502 DISASSEMBLER FROM APPLE”, DDJ VOL 1 no. 8) to work. I had more than a little trouble, till I discovered that the KIM1 Outch and Prtbyt routines were clobbering the Y register that the disassembler was using as a counter. You might like to publish my version of this program which is enclosed. [...]  »

[author : John Moorhead] #Listing #Assembly

Extract : « 

0005 * THIS IS THE VDM-1 DRIVER ORIGINATED

0010 * BY LI CHEN WANG (DR. DOBB'S JOURNAL,

0015 * VOLUME #1, ISSUE #6).

0020 *

0025 * MODIFIED TO INCLUDE SPEED CONTROL AND

0030 * GENERALLY EMULATE THE SOFTWARE DRIVER FOR

0035 * PROCESSOR TECHNOLOGY'S VDM-1 VIDEO DISPLAY.

0040 * THIS PROGRAM WILL ALSO ACT AS THE DRIVER

0045 * FOR SOLID STATE MUSIC'S VB-1 DISPLAY. [...]  »

[author : John Eaton] #Listing #Assembly #Mathematics

Extract : «  The MOS Technology KIMATH program is an arithmetic program that handles 16 digit Boating point operations. It can add, subtract, multiply and divide any two 16 digit numbers. KIMATH handles numbers in a BCD format; there is no conversion to any type of binary number. The numbers are stored in registers that are 18 bytes wide. The first byte in each register is the sign byte. Bit 7 is the sign of the mantissa and bit 6 is die sign of the exponent (0=+,l=—). The next 16 bytes contain the mantissa with one digit per byte. Each mantissa byte contains a BCD digit in the lower four bits of the byte with 0 in the upper four. The 18th byte contains the exponent in BCD which can be from 00 to 99. The entire register is in scientific notation so that the mantissa must be between 1 and 10. [...]

The 18 byte format is a very inefficient way to store a large number of variables in memory. KIMATH has routines (PSTRES, PGTARG) that can store or recall a 16 digit number from user memory and only require 10 bytes per number. [...]  »

[author : Frits van der Wateren] #Listing #Assembly #Programming

Extract : «  This GPM version is written after an article in The Computer Journal, Vol. 8, page 225, by C. Strachey. I will give a short explanation about GPM here. For further details see the article mentioned above.

GPM is a general purpose macro generator, i.e. every character from the input device is directly echoed on the output device until the start of a macro call. This call is then replaced by its body, with all evaluation of parameters etc. And the final result appears then on the output device.

A macro call is initiated by the $ sign [...]  »

[author : Jef Raskin] #OperatingSystem #Programming

Extract : «  ZAPS is a software development system for Z-80 based computers. It uses the full ZILOG mnemonics and has a nicely integrated editor. I have not tested this system, which is why this is called a product opinion. My opinion, based on the well-written documentation, is that this is a quite professional and hard-working assembly language program development system. [...]  »

[author : Phil Hughes] #Listing #Assembly

[author : Steve Newberry] #Listing #Assembly #Programming

Extract : «  KAPIAR is a general purpose macro processor for the 8080. With the exception only of a few added subroutines (ISIS I/O routines, display, signon, recovery, etc.) it is a literal translation into PLM of the RATFOR program MACRO which appears in Chapter 8 of “Software Tools” by Kernighan and Plauger. K. and P. credit Dennis Ritchie for the design, hence the name KAPIAR. The programming was carried out on the Intel MDS computer running under ISIS II at the Stanford University Microcomputer Laboratory under the supervision of Dennis Allison.

Instructions for Use

KAPIAR has six predefined macros: DEFINE, which defines other macros; IFELSE, which enables such definitions to be conditioned upon input; INCR and DECR, which increment/decrement the (numerical) argument by one; SUBSTR, which returns a substring of a given string; and DELETE, which cancels a previous definition (and reclaims the space occupied by that definition). [...]  »