Spur image format
Last updated at 6:20 pm UTC on 12 March 2018
In the Spur image format in the 32 bits version, the main improvement is the addition of immediate Characters. It improves String accessing, especially for WideString.
Historically the implementation of become has either required an extra level of indirection between an objectís address and its body, slowing down slot access, or has required a sweep of all objects, a very slow operation on large heaps. Spur, a new object representation and memory manager for Smalltalk-like languages, has neither of these deficiencies. It uses direct pointers but still provides a fast become operation in large heaps, thanks to forwarding objects that when read conceptually answer another object and a partial read barrier that avoids the cost of explicitly checking for forwarding objects on the vast majority of object accesses.
Squeak 5.0 Release Notes.