[请教]BIOS地址映射?

暴雪

原512K的ROM，现换了一个1M的ROM，windows下在 0xFFF0 0000~0xFFF7 FFFF 可以看到追加的512K的内容。
但在启动计算机时(BIOS没有初始化计算机），无法访问追加的512K的ROM。
; G2 A: |, O9 k# c% V4 n5 u(可以访问原512K的ROM 0xFFF8 0000~0xFFFF FFFF)

我的计算机用的是intel的ICH7南桥。
' L( l  b3 {2 E在手册上
FWH_SEL2—Firmware Hub Select 2 Register (LPC I/F—D31:F0)
FWH_70_IDSEL — R/W. IDSEL for two, 1-M Firmware Hub memory ranges.
/ O3 q. a9 E3 ]" yThe IDSEL programmed in this field addresses the following memory ranges:
  l! T& c8 ]" \: Z% _# FFF70 0000h – FF7F FFFFh
# `1 G# `: I2 [0 d0 F" L! MFF30 0000h – FF3F FFFFh
5 H6 e2 z: N4 p0 H7 w. ^# g7 |, ?在这里 IDSEL 如何理解。
FWH_DEC_EN1—Firmware Hub Decode Enable Register
(LPC I/F—D31:F0)
FWH_70_EN — R/W. Enables decoding two 1-M Firmware Hub memory ranges.
7 J# f! \, M. ^' N& e: E! ]0 = Disable.
1 = Enable the following ranges for the Firmware Hub
6 ~3 v- T. X: s% iFF70 0000h – FF7F FFFFh
FF30 0000h – FF3F FFFFh
除了上面的数据区域，还有其它的数据区域控制ROM到内存地址的映射吗？

谢谢大家了！！！

xtdumpling

IDSEL是LPC spec的一个信号(Device Select),
  a. |7 S# F+ p( R1 S7 N* _This one clock field is used to indicate which of multiple Firmware components is being selected.
+ V- k: u# _; @  n( U$ {The four bits transmitted over AD[3:0] during this clock are compared with values strapped onto
pins on the Firmware component. If there is a match, the Firmware component will continue to
+ r) c) y6 c3 s2 ]! [! Sdecode the cycle to determine which bytes are requested on a read or which bytes to update on a
+ K" l+ d+ R7 k( F1 {write. If there isn’t a match, the Firmware component may discard the rest of the cycle and go into
a standby power state.

详见LPC spec:
http://www.intel.com/design/chipsets/industry/25128901.pdf

0 G" i5 G+ V2 m8 E在ICH 7 中似乎就这几个吧(FWH_SEL1,FWH_SEL2,FWH_DEC_EN1,BIOS_CNTL),据我现在知道的.