Sean Kelly wrote:
Andrei Alexandrescu Wrote:
It all depends on what the largest payload is. One of my apps' largest
structures was a hash, which was almost twice as large in the 64-bit
version.
It's always possible to trim down the bits used for a pointer inside a data
structure if the savings really matters. Doing so can create some really
interesting bugs though.
The 'reduced' pointer memory model is a bad fit for D because:
1. D has to work with the corresponding C compiler, which does not support such
a memory model. This kills it right there.
2. This will kill off a lot of the benefits of having a large address space that
have nothing to do with allocating a lot of memory. I mentioned these in another
post.
3. Having to support 2 memory models doubles the work. Two libraries, two test
suite runs, more documentation, inevitable user confusion and mismatching,
everyone shipping a library has to ship two, etc.
If you must shrink the space required by pointers for a particular data
structure, I suggest instead storing an offset instead of the pointer. Then,
follow the indirection by adding said offset to a "base pointer".
