这个是linux内核setup.s中取出hd0参数的代码   有一个地方很不懂   需要各位大虾提点一下
mov    ax,#0x0000
    mov    ds,ax
!书上写的是 这里从0x41中断入口处取出hd0参数表  此时的ds = 0x0000
    lds    si,[4*0x41]         
                                                                       !问题出在这里   该代码执行以后   ds的值是多少?  0x0000还是 [4*0x41+2]?
                                                                       !按照《linux内核完全注释》这书上的意思  是从0x41中断的入口地址处读   
                                                                       !取hd0参数表  可是lds  运行以后  好像ds的值改变了   那么结合下面的
                                                                       !rep movsb  指令  拷贝的数据将是  movsb es:[di],ds:[si]  如果按照书上的意
                                                                       !思要从0x41中断入口取硬盘参数的话  ds必须为0x0000 可是我查阅了下lds
                                                                       !的用法如下:
                                                                       !指针传送指令LDS
                                                                       !LDS r16,mem         ；r16←mem,DS←mem+2
                                                                       !LDS指令将主存中mem指定的字送至r16，并将mem的下一字送DS寄存器。
                                                                       !实际上，mem指定了主存的连续4个字节作为逻辑地址，即32位的地址指
                                                                       !针。
                                                                       !mov word ptr [3060h],0100h
                                                                       !mov word ptr [3062h],1450h
                                                                       !lds si,[3060h]              ；ds=1450h,si=0100h
                                                                       !这里ds的值是改变了的    所以请问各位大虾   这段代码又是怎么回事?
                                                                       !hd0参数表的入口到底在那里?

    mov    ax,#INITSEG
    mov    es,ax
    mov    di,#0x0080
    mov    cx,#0x10
    rep
    movsb

[[it] 本帖最后由 xmy20051643 于 2008-5-7 10:35 编辑 [/it]]