This method offers a compatibility advantage because it kept the PTE (page table entry) size of 4 bytes. PSE (Page Size Extension) was the first method, which shipped with the Pentium II. IA-32 supports two methods to access memory above 4 GB (32 bits). This was the codename for SSE3 before it was released on the Intel Prescott processor (which was later added to the Pentium 4 family name). The address translation is done without the use of page tables (the PDE supplies the page frame address directly). Many of the UNIX operating systems rely on the 2 MB-page mode. PAE also supports a mode where 2-MB pages are supported. This is where the extra four bits are introduced to complete the 36-bit physical address. The Page directories and the page tables are extended to 8 byte formats, allowing the extension of the base addresses of page tables and page frames to 24 bits (from 20 bits). PAE maps up to 64 GB of physical memory into a 32-bit (4 GB) virtual address space using either 4-KB or 2-MB pages. PAE is the second method supported to access memory above 4 GB (PSE36 being the first) this method has been widely implemented. PAE is the added ability of the IA32 processor to address more than 4 GB of physical memory using Intel’s 36bit page addresses instead of the standard 32bit page addresses to access a total of 64gibibytes of RAM. It is rumoured to stand for MultiMedia eXtension or Multiple Math or Matrix Math eXtension, but officially it is a meaningless acronym trademarked by Intel. If multiple programs use the same registers by both logical CPUs, Hyper-threading can actually be known to slow down overall performance in some cases. The ability to use one physical CPU as two separate logical CPUs by taking advantage of unused CPU registers during typical operation in an attempt to make the CPU more efficient. Hyper-Transport (AMD CPUs) or Hyper-Threading (Intel CPU) The destination is a 512-byte memory location. (The FXSAVE instruction writes the current state of the x87 FPU, MMX technology, Streaming SIMD Extensions, and Streaming SIMD Extensions 2 data, control, and status registers to the destination operand. All Pentium CPUs and later have this functionality built in.įXSAVE/FXRSTOR. Used to be a separate chip on the 80486SX and earlier (called the 80487 or 80387, etc. This is where most mathematically intense calculations take place. X87 Floating Point Unit built into the CPU. Uses 64bit CPU registers and 64bit physical RAM addresses (page addresses) to support up to 1 tebibyte of RAM, which can later be extended (through future processor revisions) to 1 Pebibyte. Intel’s derivative of AMD’s 64bit CPU technology. Without CMPXCHG16B the only way to perform such an operation is by using a critical section.) This is useful for high resolution counters that could be updated by multiple processors (or cores). (CMPXCHG16B allows for atomic operations on 128-bit double quadword (or oword) data types. Also known as f00f (pronounced “foof”), an abbreviation of f0 0f c7 c8, is the hexadecimal encoding of an instruction that exhibits a design flaw in the majority of Intel Pentium, Pentium MMX, and Pentium OverDrive processors).ĬMPXCHG16B Instruction. On Intel P-4s, the TSC runs with constant frequency independent of cpu frequency when EST is used.ĬMPXCHG8B Instruction. Register showing the CPU is not Hyper-Threading capable. (A certification for experienced PCB design professionals.) Most probably this stands for Certified Interconnect Designer. Could also pertain to AMD’s 3DNow! Enhanced/Extended.Īdvanced Configuration and Power Interface.Īdvanced Programmable Interrupt Controller. Here is what I found:Ī multimedia extension created by AMD for its processors – enhancemend of MMX.ģDNOW Extensions. Most of the output is self explained, but flags is little bit difficult. Model name : Intel(R) Xeon(TM) CPU 3.06GHzįlags : fpu tsc msr pae mce cx8 apic mtrr mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe cid xtpr PROC CPUINFO FLAGS FULLI was looking to find a good explanation what are the meanings of CPU flags (shown by cat /proc/cpuinfo), but did not find full explanation.
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