[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。
(可以访问原512K的ROM 0xFFF8 0000~0xFFFF FFFF)
) N" U. S# q) i7 Y% r
我的计算机用的是intel的ICH7南桥。
3 a. ^- i. R+ |/ _) ]在手册上
FWH_SEL2—Firmware Hub Select 2 Register (LPC I/F—D31:F0)
: p& V. ?+ U4 N- P1 V6 `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:
2 E- A$ \/ [7 v2 z" g: JFF70 0000h – FF7F FFFFh
FF30 0000h – FF3F FFFFh
( o/ a. w7 Y: H1 \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.
3 B/ `: [! M6 f0 = Disable.
9 g8 u4 ]+ I) U/ u4 S  Z1 = Enable the following ranges for the Firmware Hub
$ s: ]4 t4 A7 C# [& v& K+ IFF70 0000h – FF7F FFFFh
$ V4 I& P+ Q$ U3 `% L- O  sFF30 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？

* O: ]$ M8 j$ H' J' t. M谢谢大家了！！！

xtdumpling

IDSEL是LPC spec的一个信号(Device Select),
3 _' \- \; V$ v! t3 QThis one clock field is used to indicate which of multiple Firmware components is being selected.
' w, a! q5 X) {; w( a( R  hThe four bits transmitted over AD[3:0] during this clock are compared with values strapped onto
3 q+ V% s$ n9 x: f4 c- ppins 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
5 Y% v/ |4 \! [" J3 k7 |0 Rwrite. If there isn’t a match, the Firmware component may discard the rest of the cycle and go into
a standby power state.
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详见LPC spec:
8 @( b2 m" |9 I* Ahttp://www.intel.com/design/chipsets/industry/25128901.pdf
1 @7 ?5 V3 h- w0 M7 n  F) F
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.