Re: PL/S programming language

Paul Hinman schrieb:
> Does anyone know anything about the PL/S language that IBM used for 
> operating system type code?  I don't believe that they ever released it 
> to the public but it often appeared on the micro-fiche and it looked to 
> be very PL/1 like.
> 
> Paul
> 

Hi Paul,
in the late 80es a small software house tried to ****t an Application,
which was running under VM and TSO to DPPX.
It was written in PL/AS but in the new Environment
only PL/DS was available.

PL/DS II was for 370 CPU, there was also a Version for
the 8100.
PL/DS II had a funny register allocation scheme.
It needs a base register for every 4K of the Programm Text
plus one Base Register for every 4K of automatic Variables.
Internal Procedures were not recursive, because PL/DS II
stored the Return Address in a static location
( not stack allocation scheme for internal procedures )
There were a couple of Compiler Bugs,
In case of register starvation the compiler didnt properly
manage to save registers into main storage, use them for
compilation und reload them later.
There was a macro phase before the compilation phase.

Some Differences to PLI:

DCL A CHAR(8) INIT('TEST1');
DCL B CHAR(6) INIT('WOCK' );

CALL T1(A) ;
CALL T1(B) ;

T1 : PROC ( ARG );
DCL ARG CHAR(*) ;
DCL VARIABLE CHAR(10) ;

.... VARIABLE = ARG(1:8) ;  /* SUBSTR in PLI */
.... VARIABLE = ARG(1:0) ;  /* Copies 256 chars not 0 */
....
      CALL T1(ARG) ; /* DOESNT WORK IN PLDS, NO RECURSION */

....
END T1 ;

In the second CALL the result of the substr
is not what one might expect.
The second substr the result is unexpected to someone
who isnt familiar with 370 ASM and the EX Instruction.

MfG
   Ralf