PCI Express System Architecture

Execution of Initialization Code

Prior to the discovery of the device's ROM, the configuration software has accomplished the following:

• Assigned one or more memory and/or IO ranges to the function by programming its Base Address Registers (see “Base Address Registers” on page 792).

• If the device is interrupt-driven, the interrupt routing information has been programmed into the device's Interrupt Line register (see “Interrupt Line Register” on page 791).

• In addition, if the UDF bit (this bit was in the 2.1 PCI spec and was deleted from the 2.2 PCI spec) was set in the device's configuration Status register, the user has been prompted to insert the diskette containing the PCI configuration file, or PCF, and the user selected any configuration options ...