Data Structure Chapter II experiment

Tag: Use input to modify command DOS to compute target DAO www.

1) using debug, use the e command and the a command to write instructions to memory in two ways

Machine Code Assembly Instructions

B8 4e mov ax,4e20h

Add ax,1416h

BB XX mov bx,2000h

D8 Add Ax,bx

C3 mov Bx,ax

D8 Add Ax,bx

B8 1a mov Ax,001ah

BB-XX mov bx,0026h

XX D8 Add Al,bl

XX DC Add AH,BL

XX C7 Add Bh,al

B4 XX mov ah,0

XX D8 Add Al,bl

9c Add al,9ch

The e command is the input data , the format is the-e address data

A command is used to enter the instruction, the format is a-a address and then press ENTER to start the input

(2) write the following 3 instructions to the memory unit starting from 2000:0, using these 3 instructions to calculate 2 of the 8-way

MOV ax,1

Add Ax,ax

JMP 2000:0003

(3) The ROM on the motherboard of the PC is written with a production date, in a few units of memory FFF00H~FFFFFH, please find this production date and try to change it

We modified the production date of the ROM with the e command, but the date remains the same because ROM read-only memory cannot modify the value of the memory.

4) Fill in the data in the memory unit starting with b8100h, such as:

-e b810:0000 01 01 02 02 03 03 04 04

In the actual environment A0000-BFFFF is the memory address space, so there will be the above phenomenon, but the dosbox seems to be with the actual environment in the address space distribution there are differences.

Data Structure Chapter II experiment