[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)

2 [2 n) P* L6 }. l% D/ U) _) J我的计算机用的是intel的ICH7南桥。
* a5 w- R7 p( a+ l+ `! S9 h- O在手册上
FWH_SEL2—Firmware Hub Select 2 Register (LPC I/F—D31:F0)
( g) Z2 I1 C' `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
0 f# W3 J* x0 V# F8 V/ |0 Q8 ~在这里 IDSEL 如何理解。
FWH_DEC_EN1—Firmware Hub Decode Enable Register
) O/ u: u7 ^) ~' a3 V& x(LPC I/F—D31:F0)
FWH_70_EN — R/W. Enables decoding two 1-M Firmware Hub memory ranges.
/ u" |" M; O' ~9 N3 t1 Q" ?0 = Disable.
& A6 J5 F+ A" Y+ Q9 e. F1 = Enable the following ranges for the Firmware Hub
) j) V  h) C& Z( o* SFF70 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？

5 P9 E" u, `0 z9 P1 q% P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.
+ d7 Y" P/ P3 tThe 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
/ g5 V4 `: H1 {' I9 udecode 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.
, n0 c8 o7 f: b. {: ^) l$ I& m
. _* i8 N& }  u0 K' t) }- Z详见LPC spec:
8 A' h& g, l4 o9 {! shttp://www.intel.com/design/chipsets/industry/25128901.pdf
4 g6 z: b6 l9 j/ ^; t8 U" N4 H7 p& ~
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.