Oppolzer - Informatik / Stanford Pascal Compiler

Extending PASSNAP aka SNAPSHOT

As mentioned before, PASSNAP had to be extended to be able to show the static variables, too.

When doing those changes to PASSNAP, I did some other reworking, too:

• I removed the $ chars from the internal proc names (no name conflicts, because the lower level procs now have artificial CSECT names)

• to get access to the debug information which is stored at the end of the Code CSECT, PASSNAP needs to find the length of the code at runtime, when it only has the EPA (that is: the beginning of the Code CSECT). This was stored at EPA + 10 and overwrote part of the CSECT info. I moved it behind the CSECT info, at the position 2 bytes before the STATIC CSECT pointer, that is: displacement of the initial branch instruction minus 6. PASSNAP was changed at several places according to this logic (see PTRADD-calls).

• the calls to TRACER will work no more, because TRACER still expects the code size at the old place (see some places in PASMONN.ASS). This will be reworked later.

I furthermore wanted PASSNAP to output the offsets and addresses of the variables, too - and the storage class (auto or static).

See the following example output of PASSNAP and compare it to the output of the same program (same Snapshot) in the 1979 Stanford documentation - see below in the Documentation paragraph. I added some static definitions in the main program and in the FIBONACCI procedure, which - of course - were not present in 1979.

fibonacci # 10 is ************************* ***** SNAPSHOT DUMP ***** ************************* **** SNAPSHOT WAS CALLED BY --> 'PASCAL_MONITOR' **** RUN ERROR: 1002 FROM LINE: 37 OF PROCEDURE: 'FIBONACCI' EPA address of FIBONACCI is 000205A8 Error offset is 00B4 **** SUBRANGE VALUE IS OUT OF RANGE. **** THE OFFENDING VALUE: -1 IS NOT IN THE RANGE: 0..30 **** VARIABLES FOR 'FIBONACCI *** Stack at address 0002B590 Static variables at address 00020598 J (A/0070/0002B600) = 2 ANZCALL (S/0008/000205A0) = 10 **** PROCEDURE 'FIBONACCI' WAS CALLED BY --> 'FIBONACCI' FROM LINE: 37 EPA address of FIBONACCI is 000205A8 Call offset is 0098 **** VARIABLES FOR 'FIBONACCI *** Stack at address 0002B518 Static variables at address 00020598 J (A/0070/0002B588) = 3 ANZCALL (S/0008/000205A0) = 10 **** PROCEDURE 'FIBONACCI' WAS CALLED BY --> 'FIBONACCI' FROM LINE: 37 EPA address of FIBONACCI is 000205A8 Call offset is 0098 **** VARIABLES FOR 'FIBONACCI *** Stack at address 0002B4A0 Static variables at address 00020598 J (A/0070/0002B510) = 4 ANZCALL (S/0008/000205A0) = 10 **** PROCEDURE 'FIBONACCI' WAS CALLED BY --> 'FIBONACCI' FROM LINE: 37 EPA address of FIBONACCI is 000205A8 Call offset is 0098 **** VARIABLES FOR 'FIBONACCI *** Stack at address 0002B428 Static variables at address 00020598 J (A/0070/0002B498) = 5 ANZCALL (S/0008/000205A0) = 10 **** PROCEDURE 'FIBONACCI' WAS CALLED BY --> 'FIBONACCI' FROM LINE: 37 EPA address of FIBONACCI is 000205A8 Call offset is 0098 **** VARIABLES FOR 'FIBONACCI *** Stack at address 0002B3B0 Static variables at address 00020598 J (A/0070/0002B420) = 6 ANZCALL (S/0008/000205A0) = 10 **** PROCEDURE 'FIBONACCI' WAS CALLED BY --> 'FIBONACCI' FROM LINE: 37 EPA address of FIBONACCI is 000205A8 Call offset is 0098 **** VARIABLES FOR 'FIBONACCI *** Stack at address 0002B338 Static variables at address 00020598 J (A/0070/0002B3A8) = 7 ANZCALL (S/0008/000205A0) = 10 **** PROCEDURE 'FIBONACCI' WAS CALLED BY --> 'FIBONACCI' FROM LINE: 37 EPA address of FIBONACCI is 000205A8 Call offset is 0098 **** VARIABLES FOR 'FIBONACCI *** Stack at address 0002B2C0 Static variables at address 00020598 J (A/0070/0002B330) = 8 ANZCALL (S/0008/000205A0) = 10 **** PROCEDURE 'FIBONACCI' WAS CALLED BY --> 'FIBONACCI' FROM LINE: 37 EPA address of FIBONACCI is 000205A8 Call offset is 0098 **** VARIABLES FOR 'FIBONACCI *** Stack at address 0002B248 Static variables at address 00020598 J (A/0070/0002B2B8) = 9 ANZCALL (S/0008/000205A0) = 10 **** PROCEDURE 'FIBONACCI' WAS CALLED BY --> 'FIBONACCI' FROM LINE: 37 EPA address of FIBONACCI is 000205A8 Call offset is 0098 **** VARIABLES FOR 'FIBONACCI *** Stack at address 0002B1D0 Static variables at address 00020598 J (A/0070/0002B240) = 10 ANZCALL (S/0008/000205A0) = 10 **** PROCEDURE 'FIBONACCI' WAS CALLED BY --> '$PASMAIN' FROM LINE: 46 EPA address of FIBONACCI is 000205A8 EPA address of $PASMAIN is 000206D8 Call offset is 0108 **** VARIABLES FOR '$PASMAIN *** Stack at address 0002B068 Static variables at address 00020580 I (A/0160/0002B1C8) = 10 TIME (A/0164/0002B1CC) = 13 TESTDUMP (S/0008/00020588) = 42 TESTCHAR (S/000C/0002058C) = 'Oppolzer ' **** END OF SNAPSHOT DUMP ****

Here you have the sourcecode of the 2016 version of FIBDEMO.PAS:

program FIB_DEMO ( OUTPUT ) ; (********) (*$A+ *) (********) type POS_INT = 0 .. 30 ; var I : POS_INT ; TIME : INTEGER ; static TESTDUMP : INTEGER ; TESTCHAR : array [ 1 .. 10 ] of CHAR ; function FIBONACCI ( J : POS_INT ) : INTEGER ; (******************************) (* to evaluate fibonacci # j, *) (* for j >= 0 *) (* subject to int overflow *) (******************************) static ANZCALL : INTEGER ; begin (* FIBONACCI *) ANZCALL := ANZCALL + 1 ; if J = 0 then FIBONACCI := 0 else if J = 1 then FIBONACCI := 1 else FIBONACCI := FIBONACCI ( J - 1 ) + FIBONACCI ( J - 3 ) ; end (* FIBONACCI *) ; begin (* HAUPTPROGRAMM *) TESTDUMP := 42 ; TESTCHAR := 'Oppolzer' ; for I := 10 to 25 do begin TIME := CLOCK ( 0 ) ; WRITELN ( ' fibonacci # ' , I : 3 , ' is ' , FIBONACCI ( I ) : 8 , ' (Comp.time = ' , CLOCK ( 0 ) - TIME : 5 , ' Milli Sec.)' ) ; end (* for *) end (* HAUPTPROGRAMM *) .