[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。
, U" {) L, f- K9 g9 h7 Z& I' |, O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。
8 N4 h$ ]6 ?. U& t! c(可以访问原512K的ROM 0xFFF8 0000~0xFFFF FFFF)
- x. ]  E' b1 M( ~6 Z. Y
( D1 r  O) J" i- {, i8 y我的计算机用的是intel的ICH7南桥。
在手册上
9 O$ ?  r; q: _- L+ y8 ~% u) YFWH_SEL2—Firmware Hub Select 2 Register (LPC I/F—D31:F0)
- H  N& |3 U. ~FWH_70_IDSEL — R/W. IDSEL for two, 1-M Firmware Hub memory ranges.
The IDSEL programmed in this field addresses the following memory ranges:
FF70 0000h – FF7F FFFFh
FF30 0000h – FF3F FFFFh
在这里 IDSEL 如何理解。
7 \) y6 j& i* F& K- A: u* h! JFWH_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.
0 = Disable.
( H4 m+ B5 f  B4 A: m) t1 = Enable the following ranges for the Firmware Hub
FF70 0000h – FF7F FFFFh
0 `2 c0 {* o9 v5 R* ~% v) X7 yFF30 0000h – FF3F FFFFh
9 k" c- ]3 W6 t5 Z& x. u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？
/ r& i4 M5 G% D: I6 c# F. R
/ _: H4 k* J# W- }, A7 z/ D& B谢谢大家了！！！

xtdumpling

IDSEL是LPC spec的一个信号(Device Select),
0 ~% G1 |) @8 j: S1 [3 N4 N1 nThis one clock field is used to indicate which of multiple Firmware components is being selected.
, r  u* E9 R# F6 W/ B/ YThe four bits transmitted over AD[3:0] during this clock are compared with values strapped onto
. n: u: P  k8 f$ l5 m  ^' \pins on the Firmware component. If there is a match, the Firmware component will continue to
decode the cycle to determine which bytes are requested on a read or which bytes to update on a
write. If there isn’t a match, the Firmware component may discard the rest of the cycle and go into
% f3 j) ?' `1 [4 e! }' P6 G$ @a standby power state.
3 X1 ~7 K0 R: b) s4 [& s
详见LPC spec:
http://www.intel.com/design/chipsets/industry/25128901.pdf

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.