[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。
5 J0 N: {4 d( Q( l" z6 K" B0 j  E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)

我的计算机用的是intel的ICH7南桥。
8 R; O9 `' y5 f. {( p2 t9 `3 q在手册上
6 P3 ^1 `# C' W) eFWH_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:
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.
0 = Disable.
5 L! c* g' u& H2 {; w. c: T1 = Enable the following ranges for the Firmware Hub
FF70 0000h – FF7F FFFFh
& \" H* O: k8 }3 p* s& iFF30 0000h – FF3F FFFFh
* v- w, ?8 Q/ f3 j, N  C9 x% @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？

: d0 Y6 x9 o$ y" m谢谢大家了！！！

xtdumpling

IDSEL是LPC spec的一个信号(Device Select),
3 M8 m8 a/ R& ]+ H: q9 S/ qThis 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
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.

* {' ?1 P  S- A- }$ N详见LPC spec:
( k- E4 ]: q, q9 c7 V" M: D1 Y; \1 y2 Ahttp://www.intel.com/design/chipsets/industry/25128901.pdf
7 i- N( ^) h# u* n: F6 W5 C4 O
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.