Devpac80 was one of the earliest and most popular Z80 programming tools for the CPC computer - the workhorse of many a famous software house. It was around at the same time as Zen (by Kuma). The main difference between the two was the CPM environment: Devpac80 needed it. Zen did not. Now two years on, Devpac80 has sprouted Version 2. Features have been enhanced and new ones added. But is there a place for it with the likes of Maxam II at large? Half the battle is won if the manual is readable - and doesn't assume everyone is fluent at assembly programming. The new Devpac80 comes packaged in typical HiSoft style: a looseleaf binder with 100-odd pages of instructions. Sections are provided for beginners and more advanced users. It is a pleasure to read: pages are well laid out and cause an occasional giggle - choice phrases such as "cracking a nut with a sponge" and "when silence and the A> prompt rules again...". The disk contains two versions of Devpac80. One side works under CPM 2.2; the other is for CPM Plus. This is a good idea, as all CPC machines can make use of the program. It will even run on Amstrad PCW, Einstein and MSX machines. Before you start using Devpac80, you are advised to make a workdisk. It's not a good idea to copy the whole disk, which is packed tight on both sides; just copy the files you'll frequently use. Along with the assembler, editor and monitor are utility programs that can copy files, delete a number of files, give an extended directory, convert .COM files to 3IN and vice-versa. Three parts Devpac is split into three separate parts: the editor where you enter machine-code mnemonics (or opcodes), the assembler that converts source-code (the stuff you typed in at the editor) into object-code, and the monitor that assists in removing bugs from the object- or machine-code. The editor, with the stimulating title of HDE, can be thought of as a word-processor. It produces text (or Ascii) files. If you've dabbled with Wordstar then you'll feel at home: HDE's command keys to move up or down a screenful, save a file, mark beginning and end of block are identical. If you don't already know Wordstar, you'll find its choice of keys a pain to use and hard to remember. The prospect of having to use these keys within HDE did not overjoy me. But I was glad to find a comprehensive setup file and altered all the keystrokes to suit my keyboard. A pity not more software is this versatile. As with Wordstar, there is little Devpac's editor cannot do. It offers copying, pasting and deleting blocks, complete cursor control, search-and-replace, insert and overwrite... You can also assemble, run or debug a program from HDE - handy. Assembling is done in two passes. The first pass checks the syntax and creates a symbol table. If the assembler. GEN80, encounters an error it displays the offending line and continues. The second pass generates the code, but will not occur if an error | Battle of the giants You have two competent programming utilities, but which do you go for? In its favour, Arnor's Maxam II has a superb editor and is easy to use. Against: the £80 price is excessive (presumably to compensate for high production costs) and the manual does not cover topics in enough detail. It also requires 128k and CPM Plus. The original Devpac80 cost £40 - Version 2 is the same price. The manual is compulsive reading: it teaches and is winy. Devpac can work under CPM 2.2, which means 464 and 664 owners are not left in the lurch. However, much setting up is required to tune the system to your taste. If you own one of the earlier CPC machines and mtend to create programs that will work under either CPM or the Amstrad's native operating system then I'd plump for Devpac. If, on the other hand, your budget can stretch and you intend to produce CPM files then Maxam II is probably the wiser choice. |
Slowing it down It is possible to execute a machine-code program slowly, step-by-step or by using breakpoints. These are inserted into your code and when reached return control to Promon. A very full set of breakpoint options are allowed: hard, conditional, watchpoints (let you execute a patch of code a certain number of times -especially useful for loop-testing). There are many nice touches within Devpac - more than I can list in a page. Being able to produce .REL means the output from other languages such as CBASIC, ProPascal. ProFortran and all Microsoft languages can be linked. The assembler's output can be used by other debuggers (namely those from Microsoft and Digital Research). All the CPC memory is exposed and free for you to play with if you have Devpac. It is a complete programming tool. And it scores over its rivals by being cheaper, having better documentation and being more geared towards the CPC market. It's a package I wouldn't hesitate to recommend. AA
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