The Hacker

                    by Gary Shepardson



[ This program was published in two parts in Your

  Sinclair in 1989. This text file contains the text of

  both of the articles.

  Unfortunately, Program Pitstop could, at this point in

  YS's life, have done with its own tyre change and maybe

  a new front wing, because the listings got rather mixed

  up. In the case of The Hacker, this meant that the

  first part of its listing was never - as far as I can

  tell - published.

  There was a listing with the text, all right, but it

  was the code for Quadrant Magnifier, another program

  described on the next page of that month's Pitstop.

  (With that text there was a listing for a Line Delete

  routine (yeah, yet another one), which was never even

  mentioned in the entire rest of the article!)

  The listing for the second part was (at least on the

  face of it) the correct one, but of course with only

  half of the code, nothing much can be done with this

  program. The hex data and loader for this part is what

  you'll find on the TZX.

  So, if you can't use this, why did I type it in at all?

  Well, it may be that putting this out there causes 

  someone to remember that they wrote to the author and

  got the tape, or perhaps even the original listing will

  turn up. It wouldn't be the first time.

                              Richard Bos, November 2012. ]



Now this has to be the singlemost useful program I've ever

printed here in Pitstop. I do not jest. You may have

noticed how I always brag about the size of my disassembler

in the POKE pages (they don't call me David "if it moves

POKE it" McCandless for nothing y'know). [No, indeed they

don't. They call you David "if it contains machine code

print only half of it" McCandless, mate.] Well now here's a

tiny disassembler, brain-child of one Gary Shepardson. It's

so versatile and brilliant that I decided to split it up

over two issues just to increase the suspense (and make it

look smaller).



 Cunning

The most cunning feature of this gembo is that it resides

in the top-half of the screen. This means you can load the

program you want to disect [sic - oh, the irony!] and not

have it over-written by the disassembler - a common problem

among us master hackers.



 Useful!

There are a variety of uses for Gary's program. Best is the

street credibility value. Invite your friends around, have

the disassembler 'accidently' running on your computer, and

they'll be so amazed they'll build a religion around you!

Also, this program will allow you to nose about other

people's programs, and let you search for mysterious things

like POKEs and cheat modes. And if you're UNBELIEVABLY

clever you'll be able to install it into a Multiface.

___________________________________________________________



                         Part Two



Here it is, the second part of the amazing 2K disassembler,

masterpiece of Gary Shepardson. Use the hex loader to enter

this month's code into address 31024, then load in last

month's code and save the whole lot with SAVE "hacker"CODE

30000,2048.



 To Work

To load it, use:

LOAD ""CODE 16384: RANDOMIZE USR 16384

The code loads in the top of the screen memory, so you will

see some strange things on screen. Don't worry about that,

but do worry about not clearing the screen before you exe-

cute it.

  Once loaded and run, you will be greeted with a prompt

for a START ADDRESS. You can input any decimal number from

0 to 65535 to correspond with the address you want to

disassemble from. Pressing 'Enter' scrolls instruction by

instruction. Q returns you to basic, and C allows you to

change address. Have fun.