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Unformatted text preview: d starting at physical address 4 and returns it to the CPU, which stores it in a register. 10.2. ADDRESS SPACES 487 Early PCs used physical addressing, and systems such as digital signal processors, embedded microcontrollers, and Cray supercomputers continue to do so. However, modern processors designed for generalpurpose computing use a form of addressing known as virtual addressing (Figure 10.2).
CPU chip Virtual Address (VA) 4100 Main memory 0: 1: 2: 3: 4: 5: 6: 7: Address translation
MMU CPU Physical address (PA) 4 ...
M-1: Data word Figure 10.2: A system that uses virtual addressing. With virtual addressing, the CPU accesses main memory by generating a virtual address (VA), which is converted to the appropriate physical address before being sent to the memory. The task of converting a virtual address to a physical one is known as address translation. Like exception handling, address translation requires close cooperation between the CPU hardware and the operating system. Dedicated hardware on the CPU chip called the...
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- Spring '10
- The American