[fpc-pascal] Re: assign code to a method

Angel Montesinos montesin at uv.es
Sun Feb 20 08:23:47 CET 2011

El 18/02/2011 17:59, Andrew Haines escribió:

>> From the other comments it seems like you are writing some assembly to
> memory at runtime then calling that code?

That is right.

>If so then maybe the following
> can help you.

> ...code...

> so the usage would be like so

> function TTrampolineManager.GenerateCode(args: ....): Pointer;
> begin
> try
>    Result := CurrentBlock.Position; // = @Block + Block.Cursor
>    repeat
>      WriteData(your_data, size_of_data);
>    until done;
> except
>      on e: TrampolineBlockFullException do
>        begin
>          TrampolineManager.AllocateBlock;
>          Result := GenerateCode(args);
>        end;
>    end;
> end;
> Hope this helps :)

A lot! I understand that for purposes other than trampolining, the 
essence of this is the the way of building an almost contiguous list, say

  Block: array[0..lastCodePiece] of Pointer;

of DEP executable codes inside an authorized chunk of memory, and that 
the call for assigning one of them, Block[i], to some function declared as

     otherObject.thisFunction(other args): Double;

would be

   @otherObjectInstance.thisFunction:= Block[i];

And also the way to obtain another block when one of them has
been exhausted, and the way of disposing of them, right?

Many thanks, Andrew. I intend to apply this to my old programs in 32 
bit Windows. I'll tell you about the outcome.

montesin at uv dot es

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