Registers on entry
Standard OS linkage conventions are used, and the registers on entry to the filter module are:
Figure 1. Filter module parameter list format
- R13 contains the address of a standard 18-word save area
- R14 contains the return address to the exit
- R15 contains the filter's entry point address
- R1 contains the address of a list of six fullwords that address:
- A fullword containing the
exit_type
- A fullword integer containing the
action
code - A fullword integer where the filter puts the
return_code
- A 4-fullword
handle
area - A fullword integer containing the ADATA
record_length
- The ADATA
record
The high-order bit of the last fullword address is set to one.
Figure 1 shows the six fullwords in the parameter list.
- A fullword containing the
