The Programmer's Guide to TRSDOS Version 6 - Tim Mann's Home ...

7.6.75 @RPTSK SVC-31
This SVC must be invoked only from an executing task. It will exit the task process
currently executing and replace the task's vector address in the Task Control Block
Vector Table (TCBVT) with the address following the SVC instruction. Return is made to
the foreground application that was interrupted. See the TASK PROCESSOR section in
Chapter 8, the Appendix, for detailed information on the use of this SVC.
Registers Affected: Not applicable..
7.6.76 @RREADSVC-69
This SVC will cause a reread of the current sector providing the file was opened with an
LRL between 1 and 255 or the file was accessed via character I/O (@GET/@PUT). Its most
probable use would be in applications that reuse the disk I/O buffer for multiple files
and want to reload the buffer with the proper file sector.
Registers Affected: AF.
Entry:
DE A pointer to the FCB for the file to reread.
Exit:
A Will contain an error return code if an error was encountered.
Z Set if the operation was successful.
7.6.77 @RSLCT SVC-47
The SVC is used to pass a function code 7 to a disk driver. This function will perform a
test of the selected drive to see if it is in a busy state (i.e. if the disk controller
is still executing a command). If busy, the drive will be re-selected until it is no
longer busy. See chapter 4 for additional information.
Registers Affected: AF [Note: DOS saves BC, IY; drivers should save any other
registers they use].
Entry:
C Should contain the logical drive number.
7.6.78 @RSTOR SVC-44
This SVC will restore a disk drive to cylinder 0 by passing a function 4 to a disk
driver. See chapter 4 for additional information.
Registers Affected: AF [Note: DOS saves BC, IY; drivers should save any other
registers they use].
Entry:
C Logical drive number (0-7).
Exit:
A Contains an error return code, if any.
Z Set if the operation was successful.
7.6.79 @RUN SVC-77
This SVC will load and execute a program file. Your FCB should not be located in the
memory region that will be loaded with the file you want to execute.
Registers Affected: AF, BC [Note: HL alterted on an error].
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