"IBM personal computer assembly language tutorial" - читать интересную книгу автора (Auerbach J.)

quite incompatible with CP/M and also mean that your program cannot run
under older releases of DOS. However, these calls are very nice and easy
to use. They have these characteristics

1. To open, create, delete, or rename a file, you need only a character
string representing its name.

2. The open and create calls return a 16 bit value which is simply placed
in the BX register on subsequent calls to refer to the file.

3. There is not a separate call required to specify the data buffer.

4. Any number of bytes can be transfered on a single call; no data area
must be manipulated to do this.

The "new" DOS calls also include comprehensive functions to manipulate the
new chained directory structure and to allocate and free memory.



Learning the assembler ______________________ Learning the assembler Learning the assembler Learning the assembler


It is my feeling that many people can teach themselves to use the assembler
by reading the MACRO Assembler manual if

1. You have read and understood a book like Morse and thus have a feeling
for the instruction set

2. You know something about DOS services and so can communicate with the
keyboard and screen and do something marginally useful with files. In
the absence of this kind of knowledge, you can't write meaningful prac-
tice programs and so will not progress.

3. You have access to some good examples (the ones supplied with the
assembler are not good, in my opinion. I will try to supply you with
some more relevant ones.


IBM PC Assembly Language Tutorial 14


4. You ignore the things which are most confusing and least useful. Some
of the most confusing aspects of the assembler include the facilities
combining segments. But, you can avoid using all but the simplest of
these facilities in many cases, even while writing quite substantial
applications.

5. The easiest kind of assembler program to write is a COM program. They
might seem harder, at first, then EXE programs because there is an