gtpm1m1i | TPF V4R1 Migration Guide: 3.1 to 4.1 |
Some customers have code that use the V-type constants (VCONs) that are generated by using the BEGIN and ENTxC macros as well as various tape macros. These VCONs have changed in the TPF 4.1 system. The following VCONs are no longer supported:
You do not need to reassemble objects containing these VCONs, but if the Z1 and Z2 VCONs are coded outside the BEGIN macro header, they will be flagged as illegal. If they are coded within the BEGIN macro header, they will be ignored. The Z0, Z3, and Z4 VCONs are also ignored.
Objects that contain VCONs that are no longer generated but whose function still exists (such as ZN and ZD for ENTNC and ENTDC) do not need to be reassembled because the linkage editor (LEDT) will recognize these VCONs as no longer being supported, and resolve them to the proper fast-link linkage.
Because 24 bytes of the header generated by the BEGIN macro are no longer supported, the linkage editor (LEDT) removes this part of the header from the object modules that contain it. This allows you to leave the header in pre-existing programs.
Care must be taken, however, in programs that are not link edited, such as general file keypoints. General file keypoints must be reassembled against the TPF 4.1 BEGIN macro to remove this header. This is handled in SIP Stage II. Any Z1 VCONs that appear after the BEGIN macro header will be flagged as illegal during a load. Z1 VCONs should only appear in object modules that were not reassembled.
Z6 VCONs were generated by various tape macros prior to the TPF 4.1 system to resolve tape names. If these VCONs are present in the SAL table, they will be resolved like any other VCON. If they are not in the SAL table, LEDT will resolve the VCON to the 3 characters immediately preceding it, assuming it to be a tape name. This allows programs that were not reassembled against TPF 4.1 system macro libraries to be loaded. If this automatic VCON resolution is not desired, LEDT should be assembled with SYSPARM(Z6OFF) specified as an assembler option. If LEDT is assembled with this option specified and tape name VCONs are not present in the SAL table, the loaders will issue warning messages indicating that certain VCONs could not be resolved.
LEDT uses the system allocator (SALO) table, which has a new format for the TPF 4.1 system. To run LEDT, you must generate a new system allocator (SALO) table by running the system allocator (SALO).