[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。
6 i& O. F7 B& W& E1 x' X- x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。
* i7 X: I6 g. b/ O9 }7 U! q(可以访问原512K的ROM 0xFFF8 0000~0xFFFF FFFF)
- V! _4 N6 Y; U, A
我的计算机用的是intel的ICH7南桥。
1 g- w1 |0 K! V( z在手册上
FWH_SEL2—Firmware Hub Select 2 Register (LPC I/F—D31:F0)
4 n9 S, M& A$ J; M+ aFWH_70_IDSEL — R/W. IDSEL for two, 1-M Firmware Hub memory ranges.
7 d! B, u% l$ d$ g3 L+ Q4 ?: YThe IDSEL programmed in this field addresses the following memory ranges:
9 f9 ~1 d% n9 A$ p3 S3 [6 BFF70 0000h – FF7F FFFFh
7 m2 R/ e8 Z6 t3 K3 y6 FFF30 0000h – FF3F FFFFh
4 C. P0 z+ M3 I4 A7 n9 n在这里 IDSEL 如何理解。
, u; p3 x0 N' M" hFWH_DEC_EN1—Firmware Hub Decode Enable Register
(LPC I/F—D31:F0)
# i: Y7 M' ~$ ]# ?& [$ Y$ FFWH_70_EN — R/W. Enables decoding two 1-M Firmware Hub memory ranges.
0 = Disable.
1 = Enable the following ranges for the Firmware Hub
# a, @0 D: t! C% u5 k" iFF70 0000h – FF7F FFFFh
FF30 0000h – FF3F FFFFh
8 [( G  _$ K4 U& {/ a( c! _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？

谢谢大家了！！！

xtdumpling

IDSEL是LPC spec的一个信号(Device Select),
3 E, e) k0 c0 x9 G0 Y, g' t4 UThis one clock field is used to indicate which of multiple Firmware components is being selected.
# A; Q& P& r5 |$ |The four bits transmitted over AD[3:0] during this clock are compared with values strapped onto
/ s, X, N. h- e* G5 _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
: I/ u) R& y/ s, i0 b! Hwrite. If there isn’t a match, the Firmware component may discard the rest of the cycle and go into
5 E* x$ F( y$ N" [% ^$ U$ Oa standby power state.

详见LPC spec:
/ R$ `4 N  X( r( Mhttp://www.intel.com/design/chipsets/industry/25128901.pdf
. m6 E+ }: p. K/ U; h2 T! G
: s6 G" w" b) B2 g2 \. W# r- S/ N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.