On Sat, 2015-08-29 at 02:26 +0200, Carlos E. R. wrote:
On 2015-08-29 00:39, Jim Henderson wrote:
On Fri, 28 Aug 2015 22:23:07 +0200, Per Jessen wrote:
The deficiency is that a 64bit app uses more memory than a 32bit ditto.
How much? 2x? 1.5x? 16 bytes more because of double-byte pointers?
I remember a similar discussion long ago. We did some testing with sample programs, and some would use double memory when compiled for 64 bit than when compiled for 32 bit, and not using pointers at all.
Of course, it is a problem with the program design. You can declare some type of integer array, which /may/ compile with different integer sizes (16, 32, 64 bits...) depending on the architecture. Simply because the default for the used declaration is "biggest word available" (which was not a problem when "biggest" meant "32 bit").
Of course, you can declare a different type of integer and this is not a problem anymore.
Ok, but this was with "sample test programs", it can be said. True. But that thread originated because the OP had found a particular application (sorry, I don't remember which) which used huge amounts of memory, and in 64 bits it doubled the already huge amount.
Mind, I'm not saying that "any 64 bit install uses double the memory than a 32 bit install". No. I say that "it can" use up to that. What is the figure currently, I don't know. I haven't tested. I was told, I think, but I forgot.
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