2 Replies Latest reply on Sep 22, 2013 12:35 PM by msaitoh2

    Encoding of CPUID Leaf 2 Descriptors

    msaitoh2

      Hello.

       

      I got the latest pdf of "Intel(R) 64 and IA-32 Architectures Software Developer's Manula."

       

      Table 3-22 "Encoding of CPUID Leaf 2 Descriptors" says:

       

      Value  | Type |   Description

      4FH    | TLB   |  Instruction TLB: 4Kbyte pages, 32 entries

       

      This description isn't clear whether this TLB is full associative or direct mapping.

      Which one? Direct mapping?

       

      And, I found a a typo in the same table. The description of C2H is

       

           "2MBytes/$Mbyte"

       

      This must be typo of 4Mbyte

       

      Thanks.

        • 1. Re: Encoding of CPUID Leaf 2 Descriptors
          sylvia_intel

          I would recommend you to check Table 3-12 (page 193) and Table 3-17 (page 218) of the “Intel® 64 and IA-32 Architectures -Software Developer’s Manual, Volume 2A” for more details. http://download.intel.com/products/processor/manual/325383.pdf

           

          Example 3-1 “Example of Cache and TLB Interpretation” explains how to interpret the information about caches and TLBs.

          • 2. Re: Encoding of CPUID Leaf 2 Descriptors
            msaitoh2

            Thank you for your reply.

             

            But...

             

            > Table 3-17 (page 218)


            This table describes about CPUID instruction and

            it include about EAX=02H. The detail is described in

            Table 3-22 as I wrote before.


            > Example 3-1 “Example of Cache and TLB Interpretation” explains how to interpret the information about caches and TLBs.


            Example 3-1 describes how to parse the result of CPUID with EAX =2.

            It describes how to get index values to look up table 3-22 as I said before.

             

            My question is not how to parse CPUID result. Almost all TLB entries in

            Table 3-22 describe about the associativity, e.g. direct mapped, {2,4,8,16} way

            or full associativity, but some others don't describe about the associativity.


            The TLB entires which don't describe the associativity in table 3-22 are:


            0x4f

            0x50

            0x51

            0x52

            0x5b

            0x5c

            0x5d


            I'm sorry if I'm misunderstanding.