[author : Darrel Van Buer] #Listing #Assembly #Programming #Lisp

Extract : «  As assembled here, entry is at zero. Most of the code may be anywhere in memory but all LISP data elements (CONS cells and atoms) must be in the first 32K of memory. The interpreter is completely self contained except for terminal I/O. On input from the terminal, all control characters are ignored, and thus may be freely added to improve readability. All input is parsed as literal atoms and S-expressions. An atom is any string of alphanumeric characters not over 16 characters long. [...]  »

[author : Theodore E. Bridge] #Experience #Mathematics

Extract : «  I have three reasons for writing this article. First I want to report on my experience with the FCL65E interpreter that I purchased from the 6502 Program Exchange, 2920 Moana, Reno, NV 89509:[...]

Not being able to locate a suitable BASIC interpreter for my KIM-1, I decided to give this a try. My first project was this curve fitting program. I believe the FCL65E interpreter is more compact than BASIC, possibly a little slower, but quite adequate. It has excellent diagnostics. It even has string functions.

My second reason was that I would like to see a BASIC version of this program published in DDJ, hopefully with a timing comparison. With my program, it took 40 seconds to calculate the regression coefficients in example 1 with six degrees of freedom, and 16 seconds in example 2 with four degrees of freedom. I think there may be many readers who would like to have a BASIC version of this program.

My third reason is that I want to donate this program to the public domain. It is very handy if you want to read data from tables or curves, or even if you want to make sense out of a large mass of test data. [...]  »

[author : Mike Gabrielson] #Listing #Assembly #Programming

Extract : «  Imagine that we are writing a compiler. How should the symbol table be organized? One possibility is to use a binary tree. Figure 1 illustrates a binary tree that contains seven symbols (strings representing variable names). Each symbol is contained in a node along with two pointers. The pointers are used to link together the nodes of the tree. A special pointer called the root points to the topmost node of the tree. (Computer trees grow upside down.) Grounded pointers on the bottommost nodes have nothing to point to. [...]  »

[author : David Chapman] #Languages #Book

Extract : «  Over the last few years, the tremendous proliferation of microcomputers has been accompanied by a growing reliance on BASIC as the “standard” high-level language. Nearly every microprocessor has at least one BASIC available for it; the 8080 must have at least a dozen. This is an undesirable state of affairs for a number of reasons, not the least of which is that BASIC is an atrocious language. Some people have therefore suggested that some other language should be made standard; but this is not the solution.

[...]

References

1. See, for example, Marc LeBrun, "Tilting at Windmills, Or, What's Wrong with BASIC," People's Computer Company vol. 2 no. 1 (December 1972) p. 5.

2. John McCallum, "The Altair (S-100) Bus Forum: PCC 77," BYTE vol. 3 no. 3 (March 1978) pp. 148-151.

3. Robert Suding, "Why Wait? Build a FAST Cassette Interface," BYTE vol. 1 no. 11 (July 1976) p. 46.

4. Glen A. Taylor, "Language Development: A Proposal," BYTE vo.2 no. 11 (November 1977) pp. 190-191.

5. Peter Skye, "The 8080 High Level Language Project of Peter Skye, Continued," BYTE vol. 2 no. 5 (May 1977) pp. 68-70.

6. Carl Helmers, "Is PASCAL the Next BASIC?" BYTE vol. 2 no. 12 (December 1977) pp. 6-8 and 184-185.

7. Leigh Janes, "Reactions to Previous Comments," BYTE vol. 3 no. 2 (February 1978) p. 159.  »

[author : Ancelme Roichel] #Languages

Extract : «  This new version is upward compatible with previous versions and Is the result of user requests for means to facilitate access to major pointers. In addition linking of user programs to the processor is simplified; provisions are made for up to four overlay zones defined by the user. These enhancements were made without, however, increasing the size of the processor. [...]  »

[author : Tom Williams] #Computer #Review

Extract : «  The Heathkit H-8 computer system has been on the market for over a year now and since introducing the basic system, Heath has been gradually adding accessories to its product line. Somewhat more controversy than is usual for the introduction of “another 8080-based system” surrounded the coming of the H-8. Now that most of the dust has settled, however, and Heath has followed up with the introduction of a floppy diskette system, it seems a good time for a calmer look at the H-8 and its present and future peripherals.

Since the microcomputer market is so vast and varied, any evaluation must, in addition to a critique of hardware and software, take into account the portion of the market a manufacturer appears to be aiming at and the apparent suitability of that product. Since this is the sort of exercise that makes or breaks executive careers, I will not suppose that my judgments are the “last word” on the subject.

The H-8 is an unconventional looking 8080 system and gives evidence of having been designed from the “ground up” without prejudice by previous designs. The two most striking features are the front panel display and keypad, the arrangement of the mother board with its Benton Harbor Bus ... and the lack of a cooling fan. [...]  »

[author : Paul K. Warme] #Languages

Extract : «  BASEX is a new intermediate-level language for microcomputers that combines some of the best features of both BASIC and Executable machine language code. It is almost as easy to use as BASIC and yet, it is nearly as fast and versatile as assembler language. The BASEX compiler is interactive ; that is, it permits you to enter, list, edit and run your program without the help of any auxiliary programs, such as editors or linkage editors. In this respect, BASEX is more like BASIC than FORTRAN, PASCAL and other compilers. Most BASEX commands resemble their counterparts in BASIC language, and this facilitates learning the language and translating programs from BASIC into BASEX.

The main advantages of BASEX are its speed (typically 7 to 20 times faster than BASIC) and the compact size of BASEX programs (typically at least 6K bytes smaller than similar programs written in BASIC). [...]  »

[author : Joel Swank] #Listing #Assembly #BASIC #Graphics

Extract : «  Tiny GRAFIX is a system for graphic display on small micro computer systems. It is composed of a SWTPC GT-6144 TV graphics board, Tom Pittman’s Tiny BASIC, and some machine language subroutines. It runs on a KIM-1 with 4k of memory.

The GT-6144 divides the TV screen into 6144 rectangles in a configuration of 64 horizontally (X) and 96 vertically (Y). It has its own 6144 bit memory used to maintain the display. This memory is altered by data from the computer. The data consists of X coordinates, Y coordinates and control codes. Data is received via one eight-bit output port with data ready strobe. The GT-6144 has no facility to send data to the CPU. The GT-6144 is connected to KIM by the B port of a 6820 PIA. [...]  »

[author : Keith Britton] #Interface

Extract : «  Recently Mostek and Prolog jointly announced a new bus. Such announcements appear from time to time, generating close scrutiny from a handful of intensely interested parties, mild curiosity from a somewhat larger and mostly hardware oriented group and, from most of the rest of us, no more than dull resentment at the need to increment our files of dubious mnemonics and ill chosen acronyms. The STD bus may well repay somewhat closer attention, for a surprisingly wide variety of reasons. STD is an abbreviation of the word standard and the principal importance of the bus lies in its proponents’ attempt to create a widely adopted standard rather than to merely launch a product line. Few observers will fail to find something of interest in the resulting interplay of politics, economics, history and tradition (distinction intended), mechanics, engineering decisions and tradeoffs, software/firmware/hardware interactions, logic, individual and corporate personalities. And, for those addicted to private or professional meditation, there is not only room for consideration of the immediate and future technological impact of the new bus but also of some subtle sociological implications as well.  »

[author : Paul M. Julich] #Listing #Assembly #Storage

Extract : «  The program presented allows one to copy track by track all blocks of diskette regardless of attribute. The program runs considerably faster than the INTEL supplied program using ISIS Commands for copying files. A complete diskette can be copied in 2 minutes, 45 seconds. [...]  »