[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。
( f5 w# c. ^) V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。
" ?8 U5 l9 \3 j/ ], K(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。
% H6 ^+ S; F% i) _在手册上
: [# X# w* g6 O- G" j9 RFWH_SEL2—Firmware Hub Select 2 Register (LPC I/F—D31:F0)
+ Y% e- S( m) z- e5 V  FFWH_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
* F# J. x: \. U! A在这里 IDSEL 如何理解。
/ X3 r9 p% U. a7 T7 ]2 \9 `FWH_DEC_EN1—Firmware Hub Decode Enable Register
(LPC I/F—D31:F0)
& ~9 J; h6 l( n+ z* a& J7 [, zFWH_70_EN — R/W. Enables decoding two 1-M Firmware Hub memory ranges.
8 _& d) x( i9 Q9 \0 I0 = Disable.
1 = Enable the following ranges for the Firmware Hub
9 F/ A3 m0 J) A& h9 V. L2 ~$ uFF70 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 G; g' L. ]( c/ Y* J. ?: G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.
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
! m- z9 g# K! Z  x. a; Q3 la standby power state.
# J0 `( y( F% |9 N7 [0 x
8 c0 g" K* ^9 J. ~详见LPC spec:
3 R/ b$ M9 b$ Z; n0 m  x, _http://www.intel.com/design/chipsets/industry/25128901.pdf

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.