Re: Optimization Question

Hi Peter,


thank you for your answer. To clear up things a bit:


pStage is a two dimensional array, with the integer indicies StageNr
(from 0 to 5) and i (from 0 to maximum 8). Each array element is a
struct consisting of a pointer to another table (pInsnTableLine) and a
function pointer to member function of the class the function
with the loop belongs to, too.


On Sun, 30 Jul 2000 Peter-Lawrence.Montgomery@cwi.nl wrote:


> You seem to be referring to the loop:
>
> > for (StageNr = 5; StageNr >= 0; StageNr--)
> > {
> > i = 0;
> > while (m_pStaticTable[m_TableNr][m_CurrentLine].pStage[StageNr][i].OpFuncPtr)
> > {
> > itab = m_pStaticTable[m_TableNr][m_CurrentLine].pStage[StageNr][i].pInsnTableLine;
> > (this->*m_pStaticTable[m_TableNr][m_CurrentLine].pStage[StageNr][i++].OpFuncPtr)(itab);
> > }
> > }
>
> (whereas StageNr is local). Set up a pointer to
> m_pStaticTable[m_TableNr][m_CurrentLine] before the StageNr loop.
> If pStage is an array of pointers (rather than a two-dimensional array),
> set up another pointer to (first pointer)->pStage[StageNr]
> at the spot where you initialize i = 0.


The problem is, that the compiler does not allow to call the function
that belongs to OpFuncPtr, if I set up a pointer
    m_pStaticTable[m_TableNr][m_CurrentLine] or
    (firstpointer)->pStage[StageNr]
The compiler detects that the pointer refers to a member function of the
class and tells me, that I have to call the function via the this
pointer. It might be possible if I define the help variable for the
pointers as member variables, too. I'll try that in a minute.


> If each pStage[StageNr] is a pointer to a variably-sized
> region (length possibly dependent on how high i should go), try to
> organize memory so the regions for different StageNr values are nearby,
> This should help your cache locality.


pStage[StageNr] is a fixed sized region to always 8 entries. Therefore
I guess the entries are lying one by another in memory.


Thanks for the help,


Gunnar
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