The porting effort is usually a less than if you were going from 32-bit to 64-bit for the first time. For some programs, you need zero changes.
In Qt I think the changes were stuff like:
- Use an intrinsic instead of inline assembly for cpuid.
- Change how a tagged pointer works (I.e. a 64-bit value used to store some integer bits and a pointer)
(Source: I’m the Fil-C guy and I watched the Qt porting happen from the sidelines.)
The porting effort is usually a less than if you were going from 32-bit to 64-bit for the first time. For some programs, you need zero changes.
In Qt I think the changes were stuff like:
- Use an intrinsic instead of inline assembly for cpuid.
- Change how a tagged pointer works (I.e. a 64-bit value used to store some integer bits and a pointer)
(Source: I’m the Fil-C guy and I watched the Qt porting happen from the sidelines.)