[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。
2 Q6 s; d/ E1 T4 F- L& I8 k& h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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: n- x3 Y3 l3 V6 G$ a9 D  u我的计算机用的是intel的ICH7南桥。
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.
The IDSEL programmed in this field addresses the following memory ranges:
* Y0 E5 L0 }& B4 JFF70 0000h – FF7F FFFFh
3 ^1 Y9 ?% M0 I% M; m4 u4 YFF30 0000h – FF3F FFFFh
, W3 o) m- P& d; U7 P# U; E* X, J在这里 IDSEL 如何理解。
( A7 v( ?  o; j' O* h! H+ a. zFWH_DEC_EN1—Firmware Hub Decode Enable Register
' q; g. f* H- G+ o(LPC I/F—D31:F0)
7 v' l5 X4 ^4 @7 A/ Y  k, SFWH_70_EN — R/W. Enables decoding two 1-M Firmware Hub memory ranges.
0 = Disable.
) _4 O0 h8 S, c, h: |6 `! F1 = Enable the following ranges for the Firmware Hub
FF70 0000h – FF7F FFFFh
3 S' v) J( P$ C7 W8 y8 _FF30 0000h – FF3F FFFFh
$ C& J6 G2 o1 P0 p4 T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？

, U( B, N/ H7 s: F& u( q谢谢大家了！！！

xtdumpling

IDSEL是LPC spec的一个信号(Device Select),
* A2 f% y3 M2 j3 w7 i, bThis one clock field is used to indicate which of multiple Firmware components is being selected.
- J; Z) t6 ^3 ]The four bits transmitted over AD[3:0] during this clock are compared with values strapped onto
7 e0 n" s8 {0 C1 ]8 e+ Epins 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
a standby power state.
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详见LPC spec:
http://www.intel.com/design/chipsets/industry/25128901.pdf
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! X+ b- L) M8 l/ I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.