It's a complex solution, running an asm-written 64 bit executable in the background, then communicating with it using memory mapped files and windows GDI messages to launch some 64 bit functions from a 32 bit Delphi process.
There is a sample which is able to load any 64 bit library, then call any function of this library, from a 32 bit executable.
Here are the typical steps of this solution:
- Delphi side creates a memory mapped file, either on disk, either on memory;
- It creates a mutex to notify file change;
- It lauchs a small 64 bit executable process, written in plain assembler (less than 5 KB in size!);
- Delphi client writes some data to the memory mapped file, including the function name and its parameters;
- Then it notifies the 64 bit background process via a GDI message;
- The 64 bit process receives the notification;
- Then it reads the data from the memory mapped file, and unserialize all parameters (including memory buffers);
- Then calls the 64 bit library;
- It serializes the answer into the memory mapped file;
- Then notify the Delphi client via a mutex;
- Delphi client unserialize the answer;
- Delphi 32 bit application can use the incoming data.
This solution seems to work well.
In all cases, code is worth looking at it: it's technical, but well designed!
Link is available at http://cc.embarcadero.com/Author/802978.