汇编源码系列之cdcheck

汇编源码系列之cdcheck2008-04-30这个都是过去DOS时代的汇编源码，虽然已经过去了，但是对于学习汇编还是有帮助的，汇编语言只是程序员一门基础语言，大多人掌握即可，不一定要深入研究.......

.model small    ; It"s a flaw of mine ... I really like this model
      ; I know I should do a .com with the tiny model..
      ; but I just love the small :>
.stack 100h    ; Plenty stack ;>
.386
.data    
info db 30 dup （0）
right db "Right CD$"
wrong db "Wrong CD$"
nomscdex db "MSCDEX not installed$"
.code
mov ax, @data      ; Make DS&ES point to the DATA
mov ds,ax
mov es,ax
lea edx, nomscdex
xor ebx,ebx
mov eax, 1500h    ; MSCDEX installed？
int 2fh
test ebx,ebx
jz exit      
mov edi,10h
nextloop:
mov ecx,edi
mov ax, 150bh    ; is drive ECX supported by MSCDEX （is it a cdrom？）
int 2fh
test ax,ax    ; ax！=0 if drive is CDrom
jz continiue
mov ax, 440dh
mov dx, offset info
mov bl,5
mov ch,8
mov cl,66h
int 21h      ; Fetch volume serial number （same as when you do dir）
mov eax, dword ptr [info+2]
cmp eax, 0ffb7f724h;   ;<<<<calibrate this to fit your own "right" CD
jnz continiue
lea edx, right
jmp exit
continiue:
dec edi      ; next drive
jnz nextloop
lea edx, wrong    ; not in any drive！
exit:
mov ah, 9h
int 21h
mov ax,4c00h          ; terminate！
int 21h
end