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Unformatted text preview: s. First, the CPU places the address on the system bus. The I/O bridge passes the signal along to the memory bus (Figure 6.7(a)). Next, the main memory senses the address signal on the memory bus, reads the address from the memory bus, fetches the data word from the DRAM, and writes the data to the memory bus. The I/O bridge translates the memory bus signal into a system bus signal, and passes it along to the system bus (Figure 6.7(b)). Finally, the CPU senses the data on the system bus, reads it from the bus, and copies it to register %eax (Figure 6.7(c)). Conversely, when the CPU performs a store instruction such as
movl %eax,A where the contents of register %eax are written to address , the CPU initiates a write transaction. Again, there are three basic steps. First, the CPU places the address on the system bus. The memory reads the address from the memory bus and waits for the data to arrive (Figure 6.8(a)). Next, the CPU copies the data word in %eax to the system bus (Figure 6.8(b)). Finally, the main memory reads the dat...
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- Spring '10
- The American