Delphi 32 to Delphi XE2 (64 bit) conversion

Question

I'm looking at migrating a Delphi 2007 business applications to 64 Bit using Delphi XE2. I wanted to know if there are any guidelines which will help to developers or companies, who are considering migration of there Delphi applications to 64 bit with Delphi XE2.

Any help in this regard will be highly appreciated.

Answer 1

Here is my advice.

1. First of all port the application to 32 bit Unicode.
2. Then, port to 64 bit.

I would expect step 1 to be harder than step 2. For step 1 there is Marco Cantù's Unicode whitepaper. I'm not aware of anything similar yet for 64 bit. I strongly urge you to keep these two porting tasks separate. Smaller independent tasks are always easier than one bigger combined task.

Regarding the 64 bit port I can think of the following issues to deal with:

1. All 3rd party libraries need updating.
2. All inline assembler will need attention.
3. Access to Windows API functions need looking at. A common idion is to pass Integer(MyObject). That needs to be replaced with NativeInt(MyObject).

Other than that I don't think there is much to be concerned about. The Unicode port is likely to be far more problematic.

Barry Kelly's answer here puts some more flesh on this.