读取PCI配置空间的问题

[proghua]

这段程序来自微机接口实验

.386	;386模式编译
	mov ebx,080000000h
next:
	add ebx,100h	;PCI总线配置空间容量为256个字节，及100H
	cmp ebx,081000000h
	jnz continue
	mov dx,offset pcicardnotfind	;显示未找到tpc卡提示信息
	mov ah,09h
	int 21h
	mov ah,4ch
	int 21h			;退出

不明白之处在于mov ebx,080000000h，为什么是080000000h

[xtdumpling]

看PCI规范
Bit 31 is an enable flag for determining when accesses
to CONFIG_DATA are to be translated to configuration transactions on the PCI bus.

Bit31为访问PCI配置空间的使能位.