知道了IDSEL，怎样读取PCI配置寄存器？

我要读取ALI南桥芯片M1535D的PCI配置寄存器，但只知道它的
IDSEL ＝ AD28，硬件俺是一点不懂，怎样把这个东西转换成Bus number，Device number，Function number哪？帮帮忙啊！
为什么我只能给29分哪？我有500可用分

[编辑 -  10/16/04 by  boly81]

明白了
Device Number. This is used by the M1641 to drive the IDSEL lines that select a specific PCI
device during initialization. The IDSEL lines are only driven when the Bus Number is 0h. As for
the others, the M1641 will send the configuration to a PCI or PCI bridge device.

引用第1楼boly81于2004-10-16 11:11发表的  :
明白了
Device Number. This is used by the M1641 to drive the IDSEL lines that select a specific PCI
device during initialization. The IDSEL lines are only driven when the Bus Number is 0h. As for
the others, the M1641 will send the configuration to a PCI or PCI bridge device.

用windriver之类的工具看不到么？