Address Decoding

the Downstream memory 3 address range must be set to a non-zero value when the upper 32 bits are enabled (a base address of 0 is not allowed).

.

Figure 10. Dual-Address Transaction Forwarding

 

264 Byte Boundary

 

4GB Boundary

Base + Offset

 

 

Translated

 

Base + Offset

Primary Address Map

Secondary Address Map

 

A7468-01

4.4I/O Transaction Address Decoding

The 21555 provides a mechanism where one BAR on each interface can be configured to be an I/O BAR instead of a memory BAR. The Downstream I/O or Memory 1 BAR in primary configuration space is used to decode primary bus I/O transactions for forwarding to the secondary bus. The Upstream I/O or Memory 0 BAR in secondary configuration space is used to decode secondary bus I/O transactions for forwarding to the primary bus. (See Table 37 on page 133.)

The 21555 performs direct offset address translation when forwarding I/O transactions in much the same manner that it translates memory addresses. The size of the I/O BARs can be configured to be 64 bytes, 128 bytes, or 256 bytes. Accordingly, the base address can consist of 26, 25, or 24 bits. The 21555 hardware does not restrict setting up larger I/O windows, although requesting more than 256 bytes of I/O space is a violation of the PCI Local Bus Specification, Revision 2.2. The upper bits comprising the base address of the I/O address on the primary bus is replaced with the base address written in the Downstream I/O or Memory 1 Translated BAR when initiated on the secondary bus. Similarly, the Upstream I/O or Memory 0 Translated BAR is used for upstream I/O transactions. These translated base registers are mapped in both device-specific configuration space and the 21555 CSR space.

4.4.1Indirect I/O Transaction Generation

The 21555 implements a CSR mechanism that allows access to any I/O address in the secondary or local I/O address map from the primary interface, or any I/O address in the primary or host I/O address map from the secondary interface. A pair of device-specific CSR registers contain the address and data used to initiate the I/O

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21555 specifications

The Intel 21555 is a prominent microprocessor developed by Intel, designed to cater to a variety of computing needs. This processor marks a significant step forward in Intel's lineup and underscores the company's commitment to advancing technology in personal computing, enterprise solutions, and beyond.

One of the standout features of the Intel 21555 is its advanced architecture. It utilizes a multi-core design, enabling improved performance through parallel processing. This architecture allows multiple applications to run seamlessly without a decline in speed. The cores are built on a cutting-edge manufacturing process that enhances energy efficiency while maintaining high clock speeds.

The Intel 21555 supports a wide range of technologies, including Intel Turbo Boost, which enables dynamic adjustments to the processor’s performance based on workload demands. This feature allows the processor to accelerate its speed during intensive tasks, providing users with a responsive experience when it matters the most.

Another key characteristic of the Intel 21555 is its support for integrated graphics. With Intel UHD Graphics technology, users can enjoy enhanced visuals for everyday tasks such as video playback, web browsing, and light gaming. This eliminates the need for a separate graphics card for many users, particularly in home office or light gaming scenarios.

Security is a significant focus in the design of the Intel 21555. It includes built-in hardware-based security features like Intel Trusted Execution Technology and Secure Boot. These features help protect against various types of threats, ensuring that user data remains secure from malicious attacks.

The Intel 21555 is also optimized for use with Intel's platform technologies, including Intel Optane memory and Intel Rapid Storage Technology. These technologies work together to deliver faster boot times and improved system responsiveness, making computing more efficient for users.

Furthermore, the Intel 21555 is designed to support virtualization technologies, allowing multiple operating systems to run concurrently without compromising performance. This is particularly useful for developers and businesses that rely on virtualization for testing and development environments.

In summary, the Intel 21555 is a powerful and versatile processor that reflects Intel's ongoing innovation in the computing space. With its multi-core architecture, enhanced graphics capabilities, strong security features, and advanced technologies, it stands out as an excellent choice for a wide range of applications, serving both casual users and professionals alike.
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