HP 3000 Manuals HP 3000 Manuals
PCAL INSTRUCTION CHANGE The internal PLABEL case of PCAL0 has been eliminated because of the change in the definition of PLABEL bit(0:1). Because bit(0:1) has been changed from the internal/external PLABEL flag to the logical mapping flag, the emulator/translator can no longer determine whether the label on the top of stack (TOS) is an internal or an external PLABEL. COMPATIBILITY CONSIDERATIONS Compiled programs can be transported back and forth between MPE V/E, XL Release 1.0, and XL Release 1.1 (A.10.00) because the Loaders in all three operating systems are able to convert the STTs to the proper format for both program and SL segments. WALKING BACK THROUGH STACK MARKERS To locate the INFO and/or PARM specified in the :RUN command, user code can walk back through the CM stack markers to find the bottom marker. This is usually done by looking for the stack marker where the Delta-P word is zero. Because the mapping flag is now part of the Delta-P word in stack markers, you can no longer depend on bits(0:2) being equal to zero. Therefore, the terminating marker is now the stack marker where only bits(2:14) of the Delta-P word are equal to zero. A better way to get the INFO and/or PARM values from the :RUN command is to use the GETINFO intrinsic, MPE XL Intrinsics Reference Manual (P/N, 32650-60013).