TR-DOS system functions

                +--------------------------+
                | TR-Dos system functions. |
                +--------------------------+

The  system  functions  work  with file and logical level of
disk structure. The entry point for system functions call is
15635.  If  TR-Dos  is  not  initialized,  init.  subroutine
(15649)  must be called before system calls. Function number
is placed in C register.

+-----+------------------------------------------------------+
| C   |Function                                              |
+-----+------------------------------------------------------+
| Start of work with disk                                    |
| #00 |Microcontroller reset                                 |
| #01 |Read drive parameters. A=drive No. (0-3)              |
| #18 |Read  disk parameters. 9th sector is read into buffer |
|     |placed after TR-Dos variables                         |
| Logical level                                              |
| #05 |Read sectors. HL=memory address, DE=start sector/track|
|     |B=number of sectors                                   |
| #06 |Write sectors. Parameters are the same                |
| File level                                                 |
| #07 |Write current disk catalog into stream (number in A)  |
| #08 |Read catalogue entry (A=No.) into descriptor          |
| #09 |Write catalogue entry from descriptor                 |
| #0A |Find entry, placed in descriptor, in disk catalog.    |
|     |#23814-number  of  bytes  to  match.  Returns:C=entry |
|     |found, #FF, if no                                     |
| #0B |Create  file.  HL=start  address, DE=length, name and |
|     |type are in descriptor.                               |
| #0C |Create BASIC-program (detailed previous function)     |
| #0E |Read/verify  file.  #23801:#00-read, #FF-verify. Also |
|     |can  be given: HL-start, DE-length. If A=0, start and |
|     |length  are  taken from catalog, A=3 - only length is |
|     |taken  from catalog, other cases - both HL and DE are |
|     |significant.                                          |
| #12 |Erase file. Name, type etc. are in descriptor.        |
| Service functions                                          |
| #13 |Copy 16b from HL to descriptor                        |
| #14 |Copy 16b from descriptor to HL                        |
| #17 |Choose bottom disk side                               |
| #15 |Test  physical track while formatting. Track is given |
|     |in  D, side - with previous operation. 23766 - number |
|     |of bad sectors on track                               |
+-----+------------------------------------------------------+
Other  functions  are  used  by  TR-Dos  and are useless for
programmer.

Other    themes:    TR-Dos    system   variables,   BetaDisk
microcontroller programming.
                 Igor Yudincev (igor@karlson.kai.ksu.ras.ru)
                 Text is written in IS-Editor v.1.1, 1.06.97