Nicholas Sherlock wrote:
On 19/05/2010 8:54 p.m., Reza Roboubi wrote:
Nicholas Sherlock wrote:
On 19/05/2010 3:58 p.m., Reza Roboubi wrote:
Do you know what it takes to do it? How much work for a newcomer to get
up to speed with gcc? (Maybe this should go to the developer list?)
You would need to write a memory allocator which divides the address
space into 4GB (32-bit pages). Then you could create a new malloc
routine which has an extra argument to allow you to allocate memory
from within a specified 4GB page. That way you can make all of your
allocations for a given data structure lie within the same region.
Since we are trying to _compress_ these structs in the first place
malloc'ing them individually is pointless anyway. We should probably
have some sort of custom (fixed size) allocator.
If the pointers only have to refer to memory within the same memory
allocation, and that allocation is smaller than 4GB, that's a
significantly more restricted problem. You wouldn't need a custom memory
allocator, you could just store the difference between the pointer
target and the pointer's location instead of an absolute pointer. That
sounds doable.
And that gets your ALU's doing a lot of unneeded additions and
subtractions, every time you access such pointers.
Reza.
