The art of assembly language-preparatory work (i)

The first section of the system

One, the choice of system

Because the people who really understand the computer are too few, the result of superstitious fame makes IBM pc/at occupy the market. For the popularization of computer applications, we only have improvised, for IBM Pc/at and its compatible systems, for further analysis and explanation.
Although the use of 80486 CPU microcomputer has been published, I personally think that its cost and function, not in line with the efficiency of the law. In the art work position, the value of the high and low, and the use of the material does not have an absolute relationship. What's more, we are going to prove that the use of combinatorial language production skills, can make the function of the micro-computer to maximize the marginal benefits. Therefore, this book only to 8088 CPU instructions for the discussion object, as for the program application in what model, it is not considered in the scope of this book.

II. Catalogue and disk

Suppose the reader is an experienced programmer and the computer is IBM pc/xt/at. At the beginning of the program, the system should be properly prepared. The so-called "工欲善其事, its prerequisite", if you fail to notice the details mentioned below, only one or two programs can be dealt with. When the workload is large, the program is gradually increasing, not some programs can not find, is to find a head to understand. The result is upset and impatient, so-so, write another one, barely cope with it.
Hard disk space, should be the attention of the matter is relatively large. First of all, we should properly plan the classification and application of directory and subdirectories, otherwise, when looking for a file, often have a needle in the haystack sigh. Otherwise, when you modify the program, if you put the different versions together, it will be confusedly, error-ridden.
Each programmer should have its own directory, and each of the different sets of files should have a different subdirectory, so that the clear resolution and application. And the most efficient approach is that in each subdirectory, the number of files should not be too many, and only in the same work items required by the program.
Once the hard drive is broken, all storage data will be put into water. For security, be sure to back up with a floppy disk. It's best to replicate every day, although it's a lot of trouble to copy every time, but in case the program is destroyed, that loss is incalculable.
The best way to do this is to make a special copy of the tool, generally using the. bat application, work every day, just once.

Third, the Application tool

Program writing is to control the operation of the computer, and the application tool is to translate the concept and understanding of the programmer into the instructions that can be executed continuously. As a result, there are many application tools available on the market, but they are not as useful as the writing of the program. The following list of several, as long as the use of skillful, absolutely enough.

Program writing: EDLIN, PE Ii,ws and so on.

Program compilation: Masm.exe
Early (1.25) version allows more "external title", that is, external label, but this version is limited to 8088 instructions, more appropriate for large program processing.
4.0 previous versions, at the beginning of the file, available. Xcref to produce the address table of the title and buffer. However, later versions of the version will be wrong and can no longer be used.

Program joins: Link.exe
Earlier versions of segment public ' XXXX ' some provisions, but after 3.0, in addition to the Code and data effective, other such as Byte and Word have no effect.

Program debugging: Debug.exe or Symdeb.exe and Mapsym.exe
The latter two are kits and must be purchased separately. The advantage is that in the debugging process, you can use the original program title name, and can be set "breakpoint" and so on, debugging convenient, strong function.

System processing: Pctools.exe is a very useful tool in DOS, can be used for file management, but also used to directly modify the program machine code. In addition, Ll.exe or xtalk.exe can be used when connecting. In particular, the System program debugging, often need to use the online way, to another computer as a monitor.

These tools should be uniformly placed in the \dos subdirectory, and in the System Automation program (Autoexec.bat), first set the priority channel (path), such as:

1:path=\dos;
Yes, the aforementioned tools are available in either subdirectory.