[Vm-dev] Currently executing bytecodes?

[Bert Freudenberg]

On Nov 9, 2007, at 14:10 , Mathieu Suen wrote:

>
> On Nov 9, 2007, at 1:13 PM, Michael Haupt wrote:
>
>>
>> Hi,
>>
>> On 11/9/07, André Wendt <andre.wendt at hpi.uni-potsdam.de> wrote:
>>> However, modifying the interpreter loop to:
>>>
>>> while (1) {
>>>         printNumtoFile(currentBytecode, foo->vmLogFile);
>>>         switch (currentBytecode) {
>>>         ..
>>>         }
>>> }
>>>
>>> didn't work: printNumtoFile() gets executed exactly once. I've  
>>> debugged
>>> this with GDB: currentBytecode gets modified from within the CASE
>>> statements and the program never gets past the switch() statement.
>>
>> that's most certainly because you are using a GNUified version of the
>> interpreter (right?). That one applies threading to the interpreter
>> implementation, so the loop body is not actually executed like a loop
>> body usually is. Instead, interpreter logic jumps directly to and fro
>> in the bytecode routines.
>
> Intresting could you explain how?

It replace each "case 123:" with a label and each "break" with "goto  
*jumpTable[currentBytecode]", and initializes the jumpTable with the  
labels.

> Also how to solve the problem?

Modify the BREAK macro in sqGnu.h.

- Bert -