[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。
' W/ Q2 U' `* `3 N/ }1 c: |(可以访问原512K的ROM 0xFFF8 0000~0xFFFF FFFF)
2 s8 f) n$ I$ Z; O& Q
: X" }8 l, _3 _3 h4 q7 m我的计算机用的是intel的ICH7南桥。
/ P! A3 e) o5 r7 O# o# {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:
; ]# m( G' F" ]- ?4 t8 oFF70 0000h – FF7F FFFFh
' I3 ^; S0 W2 Y/ k' GFF30 0000h – FF3F FFFFh
在这里 IDSEL 如何理解。
FWH_DEC_EN1—Firmware Hub Decode Enable Register
! V$ G6 ?) R- L2 i. G1 y. q" d5 {(LPC I/F—D31:F0)
FWH_70_EN — R/W. Enables decoding two 1-M Firmware Hub memory ranges.
0 = Disable.
- I. e7 y  t( K, B' ?  E1 = Enable the following ranges for the Firmware Hub
FF70 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？

9 l% @  L1 C: h& X6 b$ v: r. ~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.
6 n, w0 {0 |: C3 A/ HThe four bits transmitted over AD[3:0] during this clock are compared with values strapped onto
+ s' i4 L7 l0 rpins on the Firmware component. If there is a match, the Firmware component will continue to
: [- M1 U( W7 Kdecode the cycle to determine which bytes are requested on a read or which bytes to update on a
5 D' @1 t' `5 C$ d: q3 G4 X4 `write. If there isn’t a match, the Firmware component may discard the rest of the cycle and go into
$ s: b4 B% t2 b- E' h5 Q2 ~a standby power state.
  F- E" l4 p  w7 g3 L# g* @
. s2 R" L* c2 ~详见LPC spec:
& b  I) X  o, C- q2 Zhttp://www.intel.com/design/chipsets/industry/25128901.pdf

- I3 \  `7 u$ H. }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.