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To: muzosi who wrote (134794)	5/13/2001 2:26:41 PM
From: muzosi	Respond to of 186894

i should have waited till i got my morning coffee. i missed the bits portion here.

To: muzosi who wrote (134794)	5/14/2001 1:12:56 AM
From: pgerassi	Respond to of 186894

Dear Muzosi: No, not all DPFPs can do 64 bit integers. Most RISC FPUs only have the standard IEEE 796 FP 64 bits (52 bits (53 bits if you include the first bit which is 1 in all normal numbers (not NANs))mantissa, 1 bit sign, 21 bit offset exponent = 64 bits). x87 uses 80 bits, 64 bits for a non-normalized mantissa (first bit almost always a one (0 for some NANs)), 1 bit for sign, and 15 bits for a offset exponent. Thus, 64 bit integers can be used on x87 FPUs and any other that implements 64 bit mantissas or larger. On the older x86 CPUs, the FP instructions were a lot slower than FP register memory transfers. Besides, there are very small amount of programs that have working sets of 4GB or more. For most applications typically run with large amounts of memory, most of the memory is used to cache the disk, and virtual memory suffices as you can use SSD (Solid State Disk) for the additional cache. Thus with a 4KB page, a demand paged virtual memory (typical in such apps), can easily handle 16TB (the same size as virtual memory in all >=386 class CPUs) of SSD. Yes, it is easier with a 64 bit CPU, but not absolutely required (people are getting lazy lately). Pete