[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)
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# P- I' \6 r7 S我的计算机用的是intel的ICH7南桥。
在手册上
8 g+ V/ l  a1 kFWH_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.
- a& f  _& U. y/ D# c& N" \4 hThe IDSEL programmed in this field addresses the following memory ranges:
4 P" H7 u& `3 x# S% v  ]FF70 0000h – FF7F FFFFh
FF30 0000h – FF3F FFFFh
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.
$ r  R, U/ \5 {. ]% [  r9 C0 = Disable.
1 = Enable the following ranges for the Firmware Hub
0 ~6 ?" E' e5 g3 v# q! |0 t- YFF70 0000h – FF7F FFFFh
FF30 0000h – FF3F FFFFh
' S" w1 W9 F2 T. E% [3 l8 Q9 q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？

+ A: [, a! i3 M- D谢谢大家了！！！

xtdumpling

IDSEL是LPC spec的一个信号(Device Select),
7 G1 I3 |& a& C1 u& S9 YThis one clock field is used to indicate which of multiple Firmware components is being selected.
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
7 _# M% D, s6 y& m! l" v( [1 `decode the cycle to determine which bytes are requested on a read or which bytes to update on a
6 B( e0 p& N. J' hwrite. If there isn’t a match, the Firmware component may discard the rest of the cycle and go into
$ ?+ A5 _* E5 U! v' Y6 Wa standby power state.

详见LPC spec:
http://www.intel.com/design/chipsets/industry/25128901.pdf
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; K* B. K/ c4 |$ A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.