1. Experimental task 1
Task 1-1
task1_1.asm source code
task1_1. Answer the screenshot question before the end of line17 and line19
① In debug, execute until the end of line17 and before line19. Record this time: register (DS) =_ 076A ___， Register (SS) =_ 076B ___， Register (CS)= __ 076C __
② Assuming that the segment address of the code segment is X after the program is loaded, the segment address of the data segment is X__ x-2__， The segment address of stack is__ x-1__.
Task 1-2
Task task1_2.asm source code
task1_2. After debugging to the end of line17 and before line19, observe the screenshot of the values of registers DS, CS and SS and answer the question
① In debug, execute until the end of line17 and before line19. Record this time: register (DS) =__ 076A__， Register (SS) =__ 076B__， Register (CS)= _ 076C___
② Assuming that the segment address of the code segment is X after the program is loaded, the segment address of the data segment is X_ X-2___， The segment address of stack is_ x-1_.
Task 1-3
Task task1_3.asm source code
task1_3. After debugging to the end of line17 and before line19, observe the screenshot of the values of registers DS, CS and SS and answer the question
① In debug, execute until the end of line17 and before line19. Record this time: register (DS) =__ 076A__， Register (SS) =__ 076C__， Register (CS)= __ 076E__
② Assuming that the segment address of the code segment is X after the program is loaded, the segment address of the data segment is X_ x-4__， The segment address of stack is
___X-2_.
Tasks 1-4
Task task1_4.asm source code
task1_4. After debugging to the end of line17 and before line19, observe the screenshot of the values of registers DS, CS and SS and answer the question
① In debug, execute until the end of line9 and before line11. Record this time: register (DS) =__ 076C__， Register (SS) =_ 076E___， Register (CS)= _ 076A___
② Suppose that after the program is loaded, the segment address of the code segment is x__, Then, the segment address of the data segment is_ X+2___， The segment address of stack is_ X+4___.
Tasks 1-5
Based on the practice and observation of the above four experimental tasks, summarize and answer:
① For the segment defined below, after the program is loaded, the actual memory space allocated to the segment is __ ([N/16] rounding + 1)*16byte_.
② If the program Task1_ 1.asm, task1_ 2.asm, task1_ 3.asm, task1_ 4. In ASM, if the pseudo instruction end start is changed to end, which program can still be executed correctly. The reasons are analyzed and explained in combination with the conclusions obtained from practical observation.
As shown in the figure above, task 1_ 1. An error will be reported after modification. Similarly, task1_2,task1_3.
Task1_4 still works correctly.
Because end start indicates that the program starts after start:, if only end will be executed from the first line of the program, only task1_4 is the content of the code segment from the beginning, so there is only task1_4 can operate correctly.
2. Experimental task 2
Write an assembly source program to realize 160 consecutive bytes to memory units b800:0f00 ~ b800:0f9f, and fill hexadecimal data 03 and 04 repeatedly in turn.
- Assembly source code
assume cs:code code segment start: mov ax,0b800h mov ds,ax mov bx,0f00h mov cx,50h mov ax,0403h s:mov ds:[bx],ax add bx,2 loop s mov ah, 4ch int 21h code ends end start
- Screenshot of operation results
3. Experimental task 3
- Complete assembly source code
assume cs:code data1 segment db 50, 48, 50, 50, 0, 48, 49, 0, 48, 49 ; ten numbers data1 ends data2 segment db 0, 0, 0, 0, 47, 0, 0, 47, 0, 0 ; ten numbers data2 ends data3 segment db 16 dup(0) data3 ends code segment start: mov bx, 0 mov cx, 10 s:mov dx, 0 mov ax, data1 mov ds, ax add dx, [bx] mov ax, data2 mov ds, ax add dx, [bx] mov ax, data3 mov ds, ax mov [bx], dx inc bx loop s mov ah,4ch int 21h code ends end start
- Load, disassemble and debug screenshots in debug
It is required to give the debug command and screenshot to view the original value of memory space data corresponding to logical segments data1, data2 and data3 before adding data items in turn
And, after adding in turn, view the debug command and screenshot of the original value of memory space data corresponding to logical segments data1, data2 and data3
4. Experimental task 4
- Complete assembly source code
assume cs:code data1 segment dw 2, 0, 4, 9, 2, 0, 1, 9 data1 ends data2 segment dw 8 dup(?) data2 ends code segment start: mov ax, data1 mov ds, ax mov ax, data2 mov ss, ax mov sp, 16 mov bx, 0 mov cx, 8 s:push [bx] add bx, 2 loop s mov ah, 4ch int 21h code ends end start
- Load, disassemble and debug screenshots in debug
It is required to give a screenshot of the memory space corresponding to data segment data2 by using the d command before the program exits.
5. Experimental task 5
- task5.asm source code
assume cs:code, ds:data data segment db 'Nuist' db 5 dup(2) data ends code segment start: mov ax, data mov ds, ax mov ax, 0b800H mov es, ax mov cx, 5 mov si, 0 mov di, 0f00h s: mov al, [si] and al, 0dfh mov es:[di], al mov al, [5+si] mov es:[di+1], al inc si add di, 2 loop s mov ah, 4ch int 21h code ends end start
- Screenshot of operation results
Use the debug tool to debug the program, and use the g command to execute it once before the program returns (i.e. after ine25 and before line27)
What is the function of line19 in the source code?
0dfh is 1101111, the ASCII code difference between upper and lower case letters is 32, and 0dfh converts lower case letters to upper case letters.
What is the purpose of the byte data in the data segment line4 in the source code?
Modify the character color.
6. Experimental task 6
- task6.asm source code
assume cs:code, ds:data data segment db 'Pink Floyd ' db 'JOAN Baez ' db 'NEIL Young ' db 'Joan Lennon ' data ends code segment start: mov ax,data mov ds,ax mov cx,4 mov bx,0 s: mov dx,cx mov cx,4 mov si,0 p: mov al,ds:[bx+si] or al,00100000B mov ds:[bx+si],al inc si loop p add bx,16 mov cx,dx loop s mov ah, 4ch int 21h code ends end start
- Load, disassemble and debug screenshots in debug
It is required to give a screenshot of the memory space corresponding to the data segment data by using the d command before the program exits.
7. Experimental task 7
- task7.asm source code
assume cs:code, ds:data, es:table data segment db '1975', '1976', '1977', '1978', '1979' dw 16, 22, 382, 1356, 2390 dw 3, 7, 9, 13, 28 data ends table segment db 5 dup( 16 dup(' ') ) ; table ends code segment start: mov ax, data mov ds, ax mov ax, table mov es, ax mov bx, 0 mov dx, 0 mov cx, 5 s1: mov ax, ds:[bx] mov es:[dx], ax mov ax, ds:[bx+2] mov es:[dx+2], ax add bx, 4 add dx, 10h loop s1 mov bp, 5 mov cx, 5 s2: mov ax, ds:[bx] mov es:[dx], ax add bx, 2 add dx, 10h loop s2 mov cx, 5 mov dx, 10 s3: mov ax, ds:[bx] mov es:[dx], ax add bx, 2 add dx, 10h loop s3 mov cx, 5 mov dx, 5 s4: mov ax, es:[dx] mov bl, es:[dx+5] div bl mov es:[dx+8], al add dx,10h loop s4 mov ah, 4ch int 21h code ends end star
- Debug screenshot
View screenshot of original data information of table segment
Run in debug until the program exits, use the d command to view the screenshot of the memory space corresponding to the table segment, and confirm whether the information is structurally written to the specified memory as required.
Experiment summary:
The completion of this experiment needs to master the transfer of data between registers in the loop instruction and clarify the number of addresses skipped by each register.
Use the debug tool to debug the program, and use the g command to execute the screenshot before the program returns (i.e. after ine25 and before line27)