ECE4270/ECE7210 LABORATORY 1 DEVELOPING AN ASSEMBLY PROGRAM

Transcription

1 ECE4270/ECE7210 LABORATORY 1 DEVELOPING AN ASSEMBLY PROGRAM OBJECTIVE To become familiar with the development system s software: screen editor, assembler, linker, and debugger. After finishing this experiment, you should be able to do the following: 1. Use a text editor to create an assembly source code (.ASM) for a program in.exe or.com format. 2. Understand the general procedure to develop an assembly language program. 3. Use an assembler to create a file of objective code (.OBJ). 4. Use a linker to generate an executable file (.EXE or.com). 5. Learn three basic DOS service routine function calls, function 1, 2, and 9. BACKGROUND HOW TO ASSEMBLE AND LINK A SOURCE FILE: A) To Create a.com File: (assuming the filename is lab1a.asm ) The following steps outline the general procedure for creating a.com file. 1. Activate Turbo Assembler: C:> tasm /zi/l lab1a.asm 2. Activate Linker: C:> tlink /t lab1a B) To Create An.EXE File: (assuming the filename is lab1b.asm ) The following steps outline the general procedure for developing an.exe file. 1. Activate Turbo Assembler: C:> tasm /zi/l lab1b.asm 2. Activate Linker: C:> tlink /v lab1b.obj

2 PRELAB NO PRELAB REPORT is required for this lab. LABORATORY 1. Use the ConTEXT text editor (or any other editor you are familiar with) to create an.asm file (that is, an ASCII file without special formatting, as in a.doc file). Use the first sample program at the end of this document. 2. Use Turbo assembler system (TASM, TLINK) to create a.com file, an.lst file, etc Repeat parts 1 & 2 above for the other two sample files, but this time create an.exe, an.lst, etc. 4. Demonstrate these two executable files to your TA. 5. Look at the.lst files and contrast the different code generated for each sample program. 6. Use Turbo Debugger (e.g. type td lab1b.exe ) to examine both.com and.exe files and to be familiar with the following operations: a) set a watch b) view variable content in memory c) set break points d) single step through the program REPORT Answer the following questions. You will need to look at the.lst files, to use the debugger, and to read the book for the answers. 1) What does.model do? 2) What does a TINY model imply? What about MEDIUM? 3) What do.data,.code and.stack do? 4) Why the second program doesn t use them? 5) Where is the STACK for the first program? 6) What does.startup do in each case? Why are they different? 7) What is the function of the ASCII character $? (Try to remove it and see what happens) 8) What does do?

3 Sample Program Lab1a.com ;PROGRAM 1 OF LAB 1 ;FILENAME: lab1a.asm ;FILE FORMAT: COM.MODEL TINY.DATA MESSAGE DB 'ECE4270 LAB1',0DH,0AH OUTMSG DB 0DH,0AH,'THE CHARACTER YOU JUST ENTERED IS $' NEWLINE DB 0DH,0AH,'$'.CODE.STARTUP ;INITIALIZE THE PROGRAM LEA DX,MESSAGE ;PR A MESSAGE AH,1 ;READ A CHARACTER FROM KEYBOARD LEA DX,OUTMSG ;PR A MESSAGE DL,INCHAR ;OUTPUT A CHARACTER TO THE SCREEN ;E CURSOR TO NEXT LINE END

4 Sample Program Lab1b.exe ;PROGRAM 2 OF LAB 1 ;FILENAME: Lab1b.asm ;FILE FORMAT: EXE STACK_SEG SEGMENT STACK DB 100 DUP(?) STACK_SEG ENDS DATA_SEG SEGMENT 'DATA' MESSAGE DB 'ECE4270 LAB1',0DH,0AH OUTMSG DB 0DH,0AH,'THE CHARACTER YOU JUST ENTERED IS: $' NEWLINE DB 0DH,0AH,'$' DATA_SEG ENDS CODE_SEG SEGMENT PARA 'CODE' ASSUME CS:CODE_SEG, DS:DATA_SEG, SS:STACK_SEG MAIN PROC FAR AX,DATA_SEG ;INITIALIZE THE PROGRAM DS,AX AX,STACK_SEG SS,AX LEA DX,MESSAGE ;PR MESSAGE AH,1 ;READ A CHARACTER FROM KEYBOARD LEA DX,OUTMSG ;PR A MESSAGE DL,INCHAR ;OUTPUT A CHARACTER TO THE SCREEN ;E CURSOR TO NEXT LINE MAIN ENDP CODE_SEG ENDS END MAIN

5 Sample Program Lab1c.exe ;PROGRAM 3 OF LAB 1 ;FILENAME: Lab1c.asm ;FILE FORMAT: EXE.MODEL MEDIUM.STACK 100H.DATA MESSAGE DB 'ECE4270 LAB1',0DH,0AH OUTMSG DB 0DH,0AH,'THE CHARACTER YOU JUST ENTERED IS: $' NEWLINE DB 0DH,0AH,'$'.CODE.STARTUP ;INITIALIZE THE PROGRAM MAIN PROC FAR LEA DX,MESSAGE ;PR MESSAGE AH,1 ;READ A CHARACTER FROM KEYBOARD LEA DX,OUTMSG ;PR A MESSAGE DL,INCHAR ;OUTPUT A CHARACTER TO THE SCREEN ;E CURSOR TO NEXT LINE MAIN ENDP END