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请教各位高手一个PCI的问题
我们知道，PCI设备有三个空间——内存地址空间、IO地址空间和配置空间。由于PCI支持即插即用，所以PCI设备不是占用固定的内存地址空间或I/O地址空间，而是可以由操作系统决定其映射的基址。怎么配置呢？这就是配置空间的作用。
DW | Byte3 | Byte2 | Byte1 | Byte0 | Addr ---+---------------------------------------------------------+----- 0 | Device ID | Vendor ID | 00 ---+---------------------------------------------------------+----- 1 | Status | Command | 04 ---+---------------------------------------------------------+----- 2 | Class Code | Revision ID | 08 ---+---------------------------------------------------------+----- 3 | BIST | Header Type | Latency Timer | Cache Line | 0C ---+---------------------------------------------------------+----- 4 | Base Address 0 | 10 ---+---------------------------------------------------------+----- 5 | Base Address 1 | 14 ---+---------------------------------------------------------+----- 6 | Base Address 2 | 18 ---+---------------------------------------------------------+----- 7 | Base Address 3 | 1C ---+---------------------------------------------------------+----- 8 | Base Address 4 | 20 ---+---------------------------------------------------------+----- 9 | Base Address 5 | 24 ---+---------------------------------------------------------+----- 10 | CardBus CIS pointer | 28 ---+---------------------------------------------------------+----- 11 | Subsystem Device ID | Subsystem Vendor ID | 2C ---+---------------------------------------------------------+----- 12 | Expansion ROM Base Address | 30 ---+---------------------------------------------------------+----- 13 | Reserved(Capability List) | 34 ---+---------------------------------------------------------+----- 14 | Reserved | 38 ---+---------------------------------------------------------+----- 15 | Max_Lat | Min_Gnt | IRQ Pin | IRQ Line | 3C ------------------------------------------------------------------- 我现在的问题是，如何从这些信息中判断一个PCI设备是PCI桥还是AGP桥，由于他们的CLass都是0x060400，请各位高手指教。 |
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