Wang Shuang s Assembly Language Second Edition Experiment 5

There are four segments in it, which are A, B, C, and Code.

Segments a, b, and c can all be considered data segments.

Started writing like this.

mov ax,a

mov es,ax

mov ax,c

mov ds,ax

The results of paragraphs A and B are added up and finally put together in paragraph C.

====All the programs are as follows***************==assume cs:code

a segment

db 1,2,3,4,5,6,7,8

a ends

b segment

db 1,2,3,4,5,6,7,8

b ends

c segment

db 0,0,0,0,0,0,0,0

c ends

code segment

start:mov ax,a

mov es,ax

mov ax,c

mov ds,ax

mov bx,0

mov cx,8

s1:mov ax,es:[bx]

add [bx],ax

add bx,2

loop s1

mov ax,b

mov es,ax

mov ds,ax

mov bx,0

mov cx,8

s2:mov ax,es:[bx]

add [bx],ax

add bx,2

loop s2

mov ax,4c00h

int 21h

code ends

end start

The number of both cycles should be 4 instead of 8, so mov cx,8 should be changed to mov cx,4

Why can't the image be uploaded?

The start position of the CPU execution instruction is confirmed by CS:IP, and the initial CS=2000H, IP=0

i.e.: mov ax,6622h cs=2000h ip=0003hjmp 0ff0,0100 cs=0ff0h ip=0100h; The JMP command modifies the values of the CS and IP registers. The address you will be directed to is:

0ff0h*16+0100h=10000h

mov ax,2000h cs=0ff0h ip=0103hmov ds,ax cs=0ff0h ip=0105hmov ax,[0008] cs=0ff0h ip=0108hmov ax,[0002] cs=0ff0h ip=010bhWhen there is no jump command, the value of the ip always points to the position of the next command. That is, the value of the next IP address is the current IP value + the current instruction length.

With this understood, the above is not a problem.