[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。
+ }" O6 h& i% q  r- l- g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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% P3 x  K1 j+ k( _9 x我的计算机用的是intel的ICH7南桥。
# T' {$ h* u1 P+ w6 }在手册上
FWH_SEL2—Firmware Hub Select 2 Register (LPC I/F—D31:F0)
' E0 B! N9 @" f7 n! Z) vFWH_70_IDSEL — R/W. IDSEL for two, 1-M Firmware Hub memory ranges.
) M1 X5 ]9 b$ [( Q$ }1 x5 S# fThe IDSEL programmed in this field addresses the following memory ranges:
  r8 b- \) c; p( }1 y5 j3 zFF70 0000h – FF7F FFFFh
  l* m/ o  m- f. n* T: t8 A6 _FF30 0000h – FF3F FFFFh
- `  v% C. a* E- Y" r. K在这里 IDSEL 如何理解。
0 z  u7 Y+ z# GFWH_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.
& r, a3 K) S9 N2 |0 G% r1 = Enable the following ranges for the Firmware Hub
3 x: q; D, R* g; }' C& b* FFF70 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？
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谢谢大家了！！！

xtdumpling

IDSEL是LPC spec的一个信号(Device Select),
This 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
+ l: r" j& I0 D$ Adecode 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
a standby power state.
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2 X" S$ _7 t% g' B* R/ S0 T& U( i详见LPC spec:
http://www.intel.com/design/chipsets/industry/25128901.pdf

0 [: a7 ]2 t: u  {# d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.