[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 |+ z% {+ m6 ?1 Y: a$ }7 N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)

% V8 h: |5 G& b# m( S我的计算机用的是intel的ICH7南桥。
在手册上
; `$ ]: M1 R; b6 k. ]- BFWH_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
/ N! F( h; R# o# e1 w5 X/ hFF30 0000h – FF3F FFFFh
, k% `( o6 O/ N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.
/ \+ W+ m) r0 T2 q  M0 = Disable.
) M" j. b0 X) E, s2 J6 u! O; {# \1 = Enable the following ranges for the Firmware Hub
& ?& W( H1 V' J8 iFF70 0000h – FF7F FFFFh
! Q& V5 e4 b+ {) Y1 MFF30 0000h – FF3F FFFFh
0 O$ x( c: h* `5 l1 M6 c9 z2 o: E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 K0 t9 P8 Y8 j5 z0 gThis 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
: G, f# |7 {1 D9 J3 fdecode the cycle to determine which bytes are requested on a read or which bytes to update on a
- {0 A+ P8 G/ J. C! s! P  }# a) zwrite. If there isn’t a match, the Firmware component may discard the rest of the cycle and go into
a standby power state.

& o" G* ?1 M  K3 P4 E详见LPC spec:
http://www.intel.com/design/chipsets/industry/25128901.pdf
6 W5 l& p. o0 q7 e  n6 ?- C9 f
  G% w7 t* {! L! c/ f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.