John Zoltak writes:
> Learning SPL aside, I don't think this is the easiest task to learn on.
> This one would involve load library for the real CALENDAR intrinsic,
> call by plabel and retrieving the returned value from the stack. This
> isn't a task that I would like to learn SPL on.
John is right about having to call the LOADPROC routine, but it's not all that
difficult either. The easiest way to learn anything is to perform the
operation by imitation. I've included a bit of our own SPL code that does
almost exactly what's necessary:
828 <<>>
829 <<********************************************>>
830 << CPU TYPE DETERMINATION >>
831 << >>
832 << Returned Value = >>
833 << >>
834 << -1 -> I,CX >>
835 << 0 -> I(?) >>
836 << 1 -> II >>
837 << 2 -> 30,33 >>
838 << 3 -> III >>
839 << 4 -> 39,4x,5x >>
840 << 5 -> 6x,70 >>
841 << 6 -> 37 >>
842 << 7 -> micro >>
843 << 8 -> XE/LX/GX >>
844 << 16 -> 9xx >>
845 << >>
846 <<>>
847 PROCEDURE AUTHORS(CPUNUM);
848 INTEGER CPUNUM;
849 BEGIN
850 INTEGER ID,PLABEL;
851 INTRINSIC QUIT,LOADPROC,UNLOADPROC;
852 BYTE ARRAY PNAME(0:7);
853 BYTE ARRAY TEXT(0:41);
854 MOVE TEXT:="PRODUCED BY WIRT ATMAR AND DAWSON SCHAFFER";
855 PNAME(3):=TEXT(30);
856 PNAME(7):=TEXT(8);
857 PNAME(0):=TEXT(15);
858 PNAME(1):=TEXT(36);
859 PNAME(2):=TEXT(13);
860 PNAME(6):=TEXT(4);
861 PNAME(4):=TEXT(5);
862 PNAME(5):=TEXT(0);
863 CPUNUM:=0;
864 ID:=LOADPROC(PNAME,0,PLABEL);
865 IF <> THEN GOTO DEFAULT;
866 TOS:=0;
867 TOS:=PLABEL;
868 ASSEMBLE(PCAL 0);
869 CPUNUM:=TOS;
870 UNLOADPROC(ID);
871 DEFAULT:
872 END;
873 <<>>
874 <<>>
As a bit of explanation, this routine calls an undocumented intrinsic named
THISCPU. In this case, the intrinsic could have easily been called directly,
but the intention behind this routine was to make the resulting object code
complicated enough so that a decompiler (in this presumed instance, a person
who might be wanting to get around his user license), who would take the time
to find and intercept the THISCPU routine and substitute in his own, smaller
value, give up.
Because we have very few Classic customers left -- and they all seem like
extraordinarily honest folk -- I don't mind sharing this routine now. To call
the CALENDAR routine, you would basically only have to change the value in the
PNAME variable (and you don't have to make its loading procedure so cryptic
:-). THISCPU and CALENDAR both return only one variable, a 16-bit integer.
The choice that Rob faces is either to do this -- or to write his own calendar
routine from scratch (and I'm not even sure how he would do that without
calling HP's CALENDAR intrinsic somewhere in the process).
Steve Cooper and Stan Sieler showed me how to do the above 15 years ago and
it's a pleasure to return the favor now.
Wirt Atmar
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