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

7.6.10 @CLOSE SVC-60
This SVC will close a file or device. If a file is closed, the directory is updated which
is essential. All files that have been opened with UPDATE access or greater must be
closed.
Registers Affected: AF.
Entry:
DE A pointer to your File or Device Control Block.
Exit:
A Will contain any error return code.
Z Set if no error was encountered.
7.6.11 @CLS SVC-105
This SVC was installed in release 6.2.0. It will clear the video screen via an @DSP of
HOME and CLEAR-TO-END-OF-FRAME.
Registers Affected: AF
Exit:
Z Set if no error was encountered, otherwise reset (i.e. NZ).
A Contains the error code under an NZ condition.
7.6.12 @CMNDI SVC-24
This SVC passes control to the command interpreter. Your command string will be invoked
just as if it was entered in response to a "DOS Ready".
Registers Affected: Not applicable..
Entry:
HL A pointer to the start of a line buffer containing your command string
terminated with an (X'0D'). Only the first 79 characters of your
command string will be used.
7.6.13 @CMNDR SVC-25
This SVC will execute a command similarly to @CMNDI; however, upon completion of the
command, control will be returned to the address following the @CMNDR invocation. It is
necessary for all executing commands to maintain the stack pointer and exit via an RET
instruction after loading HL with the return code. It is possible to limit the execution
to DOS LIBrary commands by setting bit-4 of the CFLAG$ (see @FLAGS SVC).
Registers Affected: Dependent on command executed.
Entry:
HL A pointer to the start of a line buffer containing your command string
terminated with an (X'0D'). Only the first 79 characters of your
command string will be used.
Exit:
HL Will contain the return code of the executing command.
7.6.14 @CTL SVC-05
This SVC will output a control byte to a logical device. If a device control block is
referenced, the TYPE byte must permit CTL operation. The file access routines will ignore
@CTL requests and provide a "no error" return code. Control protocol is very unique to
each device. See chapter 3, DEVICE INPUT/OUTPUT INTERFACING, for additional information.
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