[Oberon] Assumed issue in the Lola-2 compiler

rochus.keller at bluewin.ch rochus.keller at bluewin.ch
Mon Apr 15 02:18:12 CEST 2019

Thank you once more for your feedback.

@ Paul Reed:
>> if x=-1, then I would assume the result of this assignment would be zero.
>> Unfortunately, yes.
Ok, then DIV is not a useful operator for this case. I therefor changed the REPEAT statement like this:
    REPEAT d[i] := x MOD 10H; 
    	x := ASR(x,4);  (* 'x DIV 16' corresponds to ASR(x,4) *)
    UNTIL (x = 0) OR (i = 8);
I did a couple of tests and think it works as expected. Does this look reasonable to you?

@ Joerg Straube:
I hope you don't mind if I respond in English ;-) 
Thanks for the minimized MOD expressions; I will do some tests with them. Currently I assume that my Oberon to C++ translator will just insert _MOD() funktion calls and not prescribe the implementation. I agree that the language report is rather brief and more information would be helpful. But the ' length specification is explicitly mentioned in the text which for me is sufficient to support it; and the reason I spent the effort with the Oberon to C++ translator was that I can use the original Lola compiler source code. It is also easier to recognize the literals in the generated Verilog code if the format doesn't change too much.


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