CURSOR #8 – March 1979

“And now for the bad news: Commodore decided to make a major change where you POKE the PET into upper and lower case mode (POKE 59468,14): the new ROMs give you unshifted lower case and shifted upper case (as you know, with the older machines it works the opposite way). We haven't had enough time to find many other things, but we do know that some of the changes will affect at least some of our programs.”
—Excerpted from A Cursory Glance, Issue #8

Screenshot of a 'weaving' pattern composed of PETSCII line characters.
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Author: Glen Fisher
Original file name: COVER08
PRG file: cover08.prg

This month's cover is called THE LOOM. The PET draws a series of weaved patterns composed of PETSCII lines and cycles through various configurations of over-under rules to create a variety of patterns (here is one example).

Pressing SPACE takes you to the table of contents for the issue.

Screenshot of a game of Reversi, finished with a full board.
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Author: Glen Fisher
Original file name: REVERS!
PRG file: revers.prg

REVERS! is a version of the board game Reversi, a game similar to Othello. (The only real difference between the two games is that Othello has a fixed starting position.) You can play against the PET with one of two starting board configurations. The computer opponent is strong enough to punish careless play but can easily be goaded into conceding key squares early in the game. The board shows a simple animation indicating the squares that the PET is considering for its next move; the PET's "thinking" takes some time but is not intolerably slow.

The ! on end of the filename indicates that this program has sound, but the only sound effect I noticed was a simple "plink" sound when pieces reverse colour. A small victory fanfare at the end of the game would have enhanced the sound experience.

Screenshot of a birthday list showing an invalid date of November 31.
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Author: Glen Fisher
Original file name: DBOOK
PRG file: dbook.prg

DBOOK is a simple database program for storing names and dates (such as birthdays and anniversaries.) User interaction takes place through a clumsy command-line interface and the validation is weak—the PET will happily accept November 31 as a date. Saving and loading date books requires a datasette.

Screenshot of crosshairs over a starfield.
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Author: Greg Erker
Original file name: SPACE!
PRG file: space.prg

SPACE! is a simple space shooting game. Use the number pad to move your crosshairs across the independently-scrolling starfield and press SHIFT to shoot. Targeting is tricky and only a precise hit will take down the enemy ships. Your continuously-depleting energy—needed both for flying and firing your laser—imposes a strict time limit. A machine-language subroutine placed in the cassette buffer allows the background starfield to scroll in all directions as you move your crosshairs. Overall, this is a solid and challenging game for the time.

There is a problem, though: SPACE! is only playable on early PETs. If you try to play the game on, say, a 4016, you won't be able to control your movements, because the keyboard-reading subroutine depends upon the results of PEEK(151) (the program corrects this PEEK to look at memory location 515 on first revision ROMs), and different models of PET/CBM decdode the keyboard matrix with different values. Jim Butterfield discouraged the use of PEEK(151) to read the keyboard becuase of the compatability issues that result.

If you want to run this game on a PET other than the 2001, you can patch the subroutine at line 2000 by referring to the keyboard cross-reference tables provided by Elizabeth Deal.

Screenshot of maze composed of PETSCII lines and boxes.
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Author: Howard Arrington
Original file name: MAZE
PRG file: maze.prg

In MAZE, you have to navigate a PETSCII maze collecting gold. In the game's initialzation phase, you watch as the PET constructs a complicated maze of corridors and rooms out of PETSCII characters, and you decide when the maze is ready to explore. If you let the maze grow to its maximum complexity, it becomes highly chaotic.

The only obstacle to completing the maze is your own patience. There are no tricks, traps, or opponents. Given enough time, you should always be able to collect all of the gold through brute force exploration.

Screenshot of a correctly-solved addition problem.
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Author: Donald Ross
Original file name: ADD
PRG file: add.prg

ADD is a simple addition drill program. You enter the sum one digit at a time from right to left, entering any "carries" as you go. This program is a solid way to brush up on addition, and the visual indicator for each carried digit is useful. You can specify the size and number of the addends, all the way up to problems where you have to add nine random nine-digit numbers, which becomes much easier with the "one digit at a time" input.

BASIC program listing of a custom INPUT routine and title screen layout.
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Author: Uncredited
Original file name: X
PRG file: x.prg

This month's CURSOR comes with a bonus. X is a set of BASIC scaffolding that lays out some components common to most of the programs on each tape: a copyright notice, title screen, a placeholder for instructions, and Glen Fisher's custom input routine from Issue #4. Subscribers who want to submit programs for publication are encouraged to integrate X into their work.

Although X is uncredited, I strongly suspect Glen Fisher was responsible for putting it together.

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