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Trailing-Edge - PDP-10 Archives - bb-bt99h-bb - alg10b.d09
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                 EDIT DESCRIPTIONS FOR ALGOL-10-V10B                            
  
  
                             EDIT 353    FOR ALGOL
  
  
  
  
[SYMPTOM]
  
The compiler gets an illegal  instruction  trap  on  user's  erroneous
program.
  
  
[DIAGNOSIS]
  
The compiler noticed many errors in the program  but  continued  doing
semantics checking when it should not have.  As a result, it attempted
to process an invalid statement and executed the illegal instruction.
  
  
[CURE]
  
Stop semantic checking after a "assignment to  procedure  outside  its
body" error occurs.  Continue with syntactic checking, however.
********************************************************************************
  
  
                             EDIT 354    FOR ALGOL
  
  
  
  
[SYMPTOM]
  
Program hangs or gets illegal instruction traps when /OTS:NONSHARE  is
specified to LINK with sample user program.
  
  
[DIAGNOSIS]
  
ALGOL's memory manager is doing address calculations in the left  half
of  an  accumulator.  If the address is 400000 or above (as can happen
with /OTS:NONSHARE),  an  integer  underflow  can  result.   The  trap
processor  takes  over,  but  at  a  bad  time  since  memory is in an
indeterminate state.   This  corrupts  the  program  and  causes  many
symptoms of failure.
  
  
[CURE]
  
Rewrite the memory manager code to use full accumulators  rather  than
halfwords  when  doing  address  calculations.   This  avoids  causing
underflows and the resultant traps.
********************************************************************************
  
  
                             EDIT 355    FOR ALGOL
  
  
  
  
[SYMPTOM]
  
ALGOL compiler loops printing "?COMPILATION TERMINATED" if CCL started
with no TMPCOR file.
  
  
[DIAGNOSIS]
  
The TMPCOR error handler  does  not  understand  how  to  handle  this
situation.
  
  
[CURE]
  
Print a better error message and terminate compilation in  this  case.
Clear the TMPCOR filename word after an error occurs.
********************************************************************************
  
  
                             EDIT 356    FOR ALGOL
  
  
  
  
[SYMPTOM]
  
Some ALGOL programs hang when ^C'ed or ALGDDT is started.
  
  
[DIAGNOSIS]
  
Accumulator A4 is not saved during execution of the CORE  UUO  handler
in ALGOTS.
  
  
[CURE]
  
Save A4 around the call to the code which uses it.
********************************************************************************
  
  
  
END OF  ALGOL-10-V10B