Novice entry: the difference between 32-bit and 64-bit Windows 7 and WIN XP (2)

X86-64's new set of CPU registers will provide faster execution efficiency. Registers are where the CPU internally creates and stores CPU operations and other computational results. The standard 32-bit x86 architecture includes eight general-purpose registers (GPRs), and AMD added eight more groups (R8-R9) to the X86-64, increasing the number of registers to sixteen. The X86-64 register defaults to 64-bit. Eight additional 128-bit XMM registers (also known as SSE registers, XMM8-XMM15) have been added that will provide more space for single instruction multiple data stream (SIMD) operations. These 128-bit registers will be provided in vector sum. 128-bit double precision processing in scalar calculation mode provides a hardware foundation for 3D modeling, vector analysis, and virtual reality implementation. By providing more registers, CPUs produced according to the X86-64 standard can process data more efficiently and can transfer more information in one clock cycle.

EM64T Technology

Intel officially defines EM64T as such: EM64T full name Extended Memory 64 Technology, which expands 64bit memory technology. The EM64T is an extension of the Intel IA-32 architecture, the IA-32e (Intel Architectur-32 extension). With the addition of EM64T technology, the IA-32 processor allows software to utilize more memory address space while compatible with IA-32 software, and allows software to write 32-bit linear addresses. The EM64T specifically emphasizes compatibility with 32-bit and 64-bit. Intel added eight 64-bit GPRs (R8-R15) to the new core and extended all of the original GRPs to 64 bits, which improves integer arithmetic as described earlier. Eight 128bit SSE registers (XMM8-XMM15) are added to enhance multimedia performance, including support for SSE, SSE2, and SSE3.

Intel has designed two models for processors supporting EM64T technology: legacy IA-32 mode and IA-32e mode. In the processor supporting EM64T technology, there is a component called extended feature enable register (IA32_EFER), in which Bit10 controls whether EM64T is activated. Bit 10 is called IA-32e mode active or long mode active (LMA). When LMA=0, the processor operates as a standard 32-bit (IA32) processor in the traditional IA-32 mode; when LMA=1, the EM64T is activated and the processor runs in IA-32e extended mode. under.

At present, AMD supports 64-bit technology CPUs such as Athlon 64 series, Athlon FX series and Opteron series. Intel's CPUs supporting 64-bit technology include the Xeon series using Nocona core, the Pentium 4 6 series using Prescott 2M core, and the P4 EE series using Prescott 2M core.