PEEKER

by Khalid Jamil (?)

from Your Sinclair 20 (Aug.1987) - "Program Pitstop"

[files PEEKER.*]





[This was later claimed to have been lifted from a Spanish magazine ]

[ - Microhobby #78 - and to have been written by Francisco Alexandre]

[ - see letter below.                                           JimG]





Now then, have you ever seen graphics in a game that you really liked

and thought, "Hmm, with a little bit of tickling that would be just

right for my new game!" Well, now you can! Khalid Jamil has come up with

a very tidy solution, in the form of Peeker, an amazingly short program

which allows you to look at a game's graphics or sprites to see how

they're made up.





Method



Load Peeker with LOAD "". You'll be presented with a menu screen

containing the graphics window, a small bar containing the start and end

addresses of the program you're looking at, a short box containing the

memory location presently being examined, and a menu box. The menu box

contains the words PEEK, COLOR, POINT, LOAD, and SAVE. To access each of

these options, press '6', then use 'Q' and 'A' to highlight the option,

then finally press '0' (zero) to select it. To escape from an option

press '6' again.





Basic Program



Here's the main program. Type it in and save it to tape as SAVE "PEEKER"

LINE 1. It'll load up the code blocks and auto-run.



PEEK - After loading the game, this option allows you to actually look

at the graphics in memory. Scan forwards and backwards through memory

with 'Q' and 'A'. If it looks crunched or just plain garbage, you can

expand the data sideways to make it more readable with 'O' and 'P'. If

the data seems to be off to one side, like the head of the character is

on one side and the body on the other, you can scroll the data around

with keys '5' and '8'.



COLOR - Inverses the colour of the display window.



POINT - This function points to the location in memory where the program

is stored and how much there is of it. [Toggle between the high and low

locations with 'O' and 'P'; return to the menu with 'A'. JimG]



LOAD - Allows you to load in the main machine code block of the game you

wish to inspect. If the game is too large to be resident in memory at

the same time as Peeker; it won't crash, but will just stop loading.



SAVE - Enables you to save the graphics data.





Hex Loader



[I didn't use the hex loader printed in the mag, so I've not]

[included the comments about it here.                   JimG]





Hex Dump 1



This is the first bit of code, start address = 23296, and the length =

143. Save as SAVE "PEEK CODE1" CODE 23296,143 after the Basic program on

your tape.





Hex Dump 2



This is the second bit of code [UDGs, actually. JimG], start address =

27936, and the length = 65. Save as SAVE "PEEK CODE2" CODE 27936,65

after the first code block.