汇编笔记(2) 多个段

；计算a段中各个内存值加上b段各个内存值后存放到c段中
assume cs:code

a segment
    db 1,2,3,4,5,6,7,8
a ends

b segment
    db 1,2,3,4,5,6,7,9
b ends

c1 segment
    db 0,0,0,0,0,0,0,0
c1 ends

code segment
s: 
   mov ax,a
   mov ds,ax  ;use ds point to a seg
   mov ax,c1
   mov es,ax  ;use es point to c seg
   
   mov cx,4
   mov bx,0
p1:
   mov ax,[bx]
   mov es:[bx],ax
   add bx,2
   loop p1

   mov ax,b
   mov ds,ax  ;use ds to point b seg
   mov cx,4
   mov bx,0
p2:mov ax,[bx]
   add es:[bx],ax
   add bx,2
   loop p2
   
   mov ax,4c00h
   int 21h
   
code ends

end s

（1）ds:[bx]所指向的物理地址即可读也可写；

（2）可以通过定义的段的标号作为该段的引用地址

可以手动指定数据段和栈段的位置：

assume cs:codeseg,ss:b,ds:a ;注意：这里虽然这么写，但是CPU不会直接把b当成栈，把a当成数据段，还是需要手动指定
a segment
    dw 1,2,3,4,5,6,7,8,9,0ah,0ch,0dh,0eh,0fh,0ffh
a ends

b segment
    dw 0,0,0,0,0,0,0,0
b ends

codeseg segment
start:
    mov ax,a
    mov ds,ax ;use ds to point to a seg
    
    mov ax,b
    mov ss,ax ;use ss to point to b seg,make b seg as a stack
    mov sp,16
    mov bx,0
    
    mov cx,8
s:
    push [bx]
    add bx,2
    loop s
    
    mov ax,4c00h
    int 21h
    
codeseg ends

end start