| ★ APPLICATIONS ★ PROGRAMMATION ★ Z-PACK ★ |
Z-PACK's (Amstrad Action) | Z-PACK's (Amstrad Computer User) |
The complete Z80 machine code tool-pack, according to hack P. McD. Sharper readers may have noticed a tew ads for Z-Pack ir. AA over the past few months. Zenith is a small company .based in out-of-the-way Bideford but they could be going a long way, judging by Z-PacK a new product aimed at the more serious enthusiast. It's a toolkit for examining the routines hidden away in machine code programs, and could well prove popular among those many people who enjoy hacking for fun and for Cheat Mode. On the disk are two slightly different versions one suitable for 64K machines, the other containing more features to exploie the exlra memory of a 128K machine. Enclosed with the disk is a small. Ab manual, printed rather than photocopied Well written and informative, it explains well just what you get for your eleven quid. The memory of an editor When you run Z-Pack. you are taken to the first option, Memory Editor. A bewildering array of information is placed onto the screen. Time to get the manual out to decipher it all... In a memory editor (we've printed some ir. AA) you have a pointer Dial indi cates a particular byte in memory. Onscreen a list of the bytes is displayed, generally ir. Ascii as well as hexadecimal. Using the cursor keys increases or decreases the memory pointer, and the screen display scrolls to show the new memory locations. Typing with the numbers 0-9 or the letters A-F (upper or lower case) alters the contents of the byte which the memory pointer is locking at. The memory pointer is automatically incremented, so that typing large amounts of data can be aone at a fair old speed. Using it is easy: you just scroll around looking for a likely piece of code. Ascii messages are easily seen, so changing program stait up messages, high score tables and similar data is pretty simple. For the technical, pressing the clr key toggles between interpreting bit 7 of the data and ignoring it. Similarly tab lets you alter the Ascii interpretation of the memory as opposed to the default hex. Running across the top of the screen are some useful tidbits about the program. (If you're not into assembler they won't mean very much, and can safely be ignored.) First theres the version (64/128), update number and the address of the memory pointer Next comes the byte's contents in hex and binary values, and then the address made by combining the present byte with the next byte in standard 'lo-hi' format, displayed in hex and decimal.
Once you have found some oode to look at, the disassemble option is ready and waiting for you to start looking at it. The options available with this function arc good you can senu to screen, which means disassemble to an onscreen window Pull to screen, where you use the whole display for disassembly Block to printer and Block to disk, where a file is sent to the relevant device In the latter case, this could enable you to load the source code into an assembler - necessary for larger scale changes to code. Actually marking a block out for the two previous features is no hassle All you have to do is go to the start of where you wish to mark, press a key. then go to the end and press a key. Of final note in the league of major features is the ROM/RAM selection. The lower ROM can be switched on and off as can any of the upper ROMs from 0-251 (If anyone actually has 251 upper ROMs connected, we would be delighted to hear from you Four megabytes is as we technical bods say. a fair old bit ot memoty) If you have extra RAM banks these can be paged in on the 128K edition, and the screen base set to either the normal (49162) or lower (4000) sotting The manual's explanation of the extra memory, however, is disappointing. Other commands have been included to help you control and understand Z-Pack better, including a help page, the ability to access nearly all the Amsdos commands (exception=,jser), start execution of a machine code program, set the memory pointer without endlessly scrolling the text, and so on. Breakpoints are also implemented although they are not conditional. Most interesting among these is a rather nifty hex calculator How often, when machine code programming do you reach for a pencil and papei to do a quick sum"? Not only can Z Pack add, subtract, divide and multiply but it can also perform logical opera Lioiis or. and and xor The answer is displayed in hex. decimal and binary This function is genuinely useful, and it's the first lime I've seen it in a disassembler. Without doubt this is one of the best disassemblers around The screen update is fast, the disassembler RAM scroll up as well as down and the calculator saves messing about. Z Pack lacks conditional breakpoints, however, which can be vital and it taxes a lot of memory around 10K It can't break into machine code on its own other programs must be written or bought foi that Any chance of a ROM or Multiface version, Zenith? AA |
|  |
|
Leftovers
