Книга: Embedded Linux Primer: A Practical, Real-World Approach
3.1.3. Freescale MPC7448
3.1.3. Freescale MPC7448
The Freescale MPC7448 contains what is referred to as a fourth-generation PowerPC core, commonly called G4.[18] This high-performance 32-bit processor is commonly found in networking and telecommunications applications. Several companies manufacture blades that conform to an industry-standard platform specification, including this and other similar stand-alone Freescale processors. We examine these platforms in Section 3.3, "Hardware Platforms," later in this chapter.
The MPC7448 has enjoyed popularity in a wide variety of signal-processing and networking applications because of the advanced feature set highlighted here:
• Operating clock rates in excess of 1.5GHz
• 1MB onboard L2 cache
• Advanced power-management capabilities, including multiple sleep modes
• Advanced AltiVec vector-execution unit
• Voltage scaling for reduced-power configurations
The MPC7448 contains a Freescale technology called AltiVec to enable very fast algorithmic computations and other data-crunching applications. The AltiVec unit consists of a register file containing 32 very wide (128-bit) registers. Each value within one of these AltiVec registers can be considered a vector of multiple elements. AltiVec defines a set of instructions to manipulate this vector data effectively in parallel with core CPU instruction processing. AltiVec operations include such computations as sum-across, multiply-sum, simultaneous data distribute (store), and data gather (load) instructions.
Programmers have used the AltiVec hardware to enable very fast software computations commonly found in signal-processing and network elements. Examples include fast Fourier Transform, digital signal processing such as filtering, MPEG video coding and encoding, and fast generation of encryption protocols such as DES, MD5, and SHA1.
Other chips in the Freescale lineup of stand-alone processors include the MPC7410, MPC7445, MPC7447, MPC745x, and MPC7xx family.
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