9052 请教

4.2.1.5.3 Direct Slave Example

A 1 MB prefetchable Local Address Space
encompassing Local Bus Addresses 01200000h
through 012FFFFFh is to be configured for Local
Address Space 0. Assume the BIOS System
Resource Manager allocates 1 MB with a PCI Base
Address of 34500000h. The Local memory is then
accessible at PCI Addresses 34500000h through
345FFFFFh.
a. Program the serial EEPROM as follows:
• Range―FFF00008h [1 MB, decode the upper
12 PCI Address bits, and set the Prefetchable
bit (LAS0RR[3]=1)].
• Local Base Address (Remap)―01200001h
(Local Base Address for PCI-to-Local
accesses). Bit 0 must be set to enable address
decoding (LAS0BA[0]=1).
想请问一下在range步骤中,fff00008h中的fff是指对应pci基址中的345吧?但对于las0rr［３］，如果我的pci基址是00000fffh，那这个
las0rr[3]不是没地方放了！是不是基址只使用高位，不使用低位，
低位一定用来设置las0rr［３］?