EDT is called in accordance with the standard rules for program linkage. It can also be called using higher-level programming languages. Before program entry in EDT, the registers must be loaded as follows:
Register | Data area |
|
|
PARAMETERLIST
Users must create this data area themselves.
The parameter list must contain the addresses of all the control blocks and defined data fields from which EDT can extract the required information (e.g. statement sequences, message texts etc.).
The parameter list is dependent on the function of the call. The descriptions of the individual functions indicate the parameters that need to be specified (see section “Statement functions” and “Logical record access functions”).
SAVEAREA
Register save area (18 words, DC 18F'0') which must be created by the caller. EDT saves the registers here.
RETURN
The return address in the calling program. The program is continued at this address when EDT is terminated.
ENTRY
The IEDTGLE module contains a separate entry point address for each function:
Entry point | Function |
| Read the EDT version number |
| Execute an EDT statement sequence |
| Execute an EDT statement sequence |
| Read a record |
| Read a marked record |
| Write a record |
| Mark a record |
| Delete a record range |
| Modify the line number |