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

Registers Affected: AF, BC.
Entry:
BC delay count
7.6.60 @PEOF SVC-65
This SVC will position an open file to the end-of-file position. If the SVC is
successful, an error 28 - "End of file encountered" will be returned.
Registers Affected: AF.
Entry:
DE A pointer to the FCB of the file to position.
Exit:
A Will return the error return code.
7.6.61 @POSN SVC-66
This SVC will position a file to a logical record. This will be useful for positioning to
records of a random access file. When the @POSN routine is used, Bit 6 of FCB +1 is
automatically set to ensure that the EOF will be updated when the file is closed only if
the NRN exceeds the current ERN. This action will guard against any inadvertant
deallocation of space in the random access file. A file can be extended by positioning to
its EOF (see @PEOF) then writing to it.
Registers Affected: AF.
Entry:
DE A pointer to the FCB for the file to position.
BC Contains the logical record number for the positioning.
Exit:
A Will contain an error return code if an error was encountered.
Z Set if the operation was successful
7.6.62 @PRINT SVC-14
This SVC will output a message string to the printer device, *PR. The message string must
conform to the syntax specified under @DSPLY.
Registers Affected: AF, DE.
Entry:
HL A pointer to the message to be output.
Exit:
A Will contain an error code if the SVC was unsuccessful.
Z Set if the SVC was successful.
7.6.63 @PRT SVC-06
This SVC will output a byte to the printer device, *PR. All character codes are passed
unaltered to the device unless the forms filter is filtering the device. If the *PR
device is not available, the SVC will time out after approximately 10 seconds and return
a "Device not available" error.
Registers Affected: AF, DE.
7-32