COURSE OUTCOMES OF MICROPROCESSOR AND PROGRAMMING

1. COURSE OUTCOMES OF MICROPROCESSOR AND PROGRAMMING Visit for more Learning Resources

2. THE ART OF ASSEMBLY LANGUAGE PROGRAMMING CHAPTER 4

3. Program development steps • Defining the problem • Algorithm • Flowchart • Initialization checklist • Choosing instruction • Converting algorithm to assembly language program

4. Defining the problem • The first steps in writing program is to think very carefully about the problem that you want to solve. • The problem is given in the form of statement or mathematical expression • Read the problem carefully and understand the problem • Expand the problem to get a clear ,concise and accurate description • E.g: read temperature from sensor

5. Algorithm • An algorithm is a step-by-step instruction require to solve any problem. • An algorithm consist of a set of explicit , finite steps which when carried out for a given set of initial condition,produce the output.

6. Flowchart • The flowchart is graphically representation of the program operation • The specific operation is represented by graphical symbol such as circle ,rectangle , diagonal, square, parallelogram.

7. Initialization checklist • In program there are many variables, constant ,and various part of the system such as segment registers ,flags ,stack , programmable port which must be initialize properly. • The best way to approach the initialization task is to make the checklist of the entire variables, constants, registers , flags &ports

8. Choosing instructions • Next steps is to choose proper instruction that performs your problem’s operation • This is an important step that breaking down the programming problems sequences of steps  easy to find the instruction solve the problem

9. Converting algorithm into assembly language • In assembly language program a first step is to set up & declare the data structure that the algorithm will be working with then write down the instruction required for initialization at the start of the code section. • Determine the instruction required to implement the major actions in the algorithm

10. Assembly language program development tools 1)Editor: • An editor is a program which helps you to construct your assembly language program in right format- translate it correctly in machine language • So you can type your program using editor • Form of the program source program. • DOS based editor such as EDIT ,wordstar &norton editor

11. Assembler • An assembly is a program that translate the program-into binary code for each instruction .i.e: machine code and generate the file called as object file with extension .obj • Example: tasm ,masm

12. Linker • A linker is a program which combines if requested more than one separately assembled module into one executable program • Example: Tlink

13. Debugger • Debugger is a program that allows the execution of program in single step mode under the control of the user. • The process of locating & correcting errors using a debugger is known as debugging • Example: DOS debug command , borland’s turbo debugger.

14. Program development process • Source file creation • Object code generation • Executable file creation • Program running • Program testing • Program debugging

15. Data definition direction 1) DB • The directive DB  to define a byte type variable • It can be used to single or multiple byte variable. • The range of values that can be stored in a byte is 0 to 255 for unsigned number & -128 to +127 for signed numbers • Name_of_variable DB initalization_value(s)

16. Dw: define word • The directive Dw to define a word type • It can be used to define single or multiple word variables • The range is 0 to 65535 for unsigned numbers & -32768 to +32767 • General form: Name of variable DW initialization value(,s)

17. DD: define double word • DD used to define a double word type • Can be used to define single or multiple double word variable i.e 4 byte • Range is 0 to 2^32-1 for unsigned numbers • -2^32-1 to 2^32-1-1for signed numbers • General form: Name_of_variable DD Initalization_value(,s) Example: NUM DD ?=allocate four memory locations

18. DQ: define quad word • DQ is used to define a quad word type • It can be used to define single or multiple quad word variable • Range is 0 to 2^64-1 for unsigned numbers • -2^64-1 to 2^64-1-1 for signed numbers • It is used in the math coprocessor instruction where large no are used in computation • General form: Name_of _variable DQ initalization_value(,s) Example: NUM DQ ? = allocate 8 memory location

19. DT: define ten byte • DT: used to define a ten byte type variable • Can be used to define a single or multiple 10 byte variable. • Range 0 to 2^80-1 for unsigned number • -2^80-1 to 2^80-1-1 for signed integer numbers • The floating point numbers range from 10^-4932 to 10^4932 • The DT type variables useful in math coprocessor instruction where large numbers are used in computation

20. -General form: • Name_Of _ variable DT Initalization_Value( , s) • Example: • NUM DT ? = allocate ten memory locations • TABLE DT 1,2,3,564,5689 = allocate fifty memory location -

21. LABEL • The directive LABEL enables you to redefine the attribute of a data variable or instruction label. • General form: Variable_name LABEL type_specifier Example: • TEMP LABEL BYTE • NUM LABEL WORD

22. ALIGN : alignment of memory address • The directive ALIGN - to force the assembler to align the next data item • General form: ALIGN Numeric_value -the number must be a power of 2 such as 2 ,4 ,8 ,16 Example: ALIGN 4

23. STRUCT: structure declaration • STRUCT - to declare the data type which is primary collection of data type • Structure declaration allows the user to define a variable which has more thatn one data type. • General form: Structure _name STRUCT …………. ; sequence of DW ,DD directives for declaring ; ; field ………… structure_name ENDS • Example: Employee STRUCT emp_num DW ? emp_name DB 25 DUP(0) emp_dept DB 30 DUP (0) Employee ends

24. Accessing structure variable field: • - The structure variable field can be accessed by using a dot(.) operator known as the structure access operator. • General form: • Structure_variable. Field _name • Example: • here structure variable name is emp1 • emp1.emp_num • emp1. emp_name • emp1.emp_dept

25. EQU:equate to • The EQU directive  declare the symbols which some constant value is assigned. • Such symbolscalled as macro symbols • Macro assembler will replace every occurrences of the symbols • Macro increase readability of program • General form: symbols_name EQU Expression Example: NUM EQU 100

26. ORG: originate • ORGassign the location counter with the value specified in the directive • Helps in placing the machine code in the specified location while translating the instruction into machine codes by the assembler. • This feature useful in buliding device drivers • General form: ORG [$] Numeric_value Example: ORG 100h

27. Program organization directives 1) ASSUME : • Assume informs the assembler the name of the logical segment that should be used for a specified segment. • General form: ASSUME seg_reg: Seg_name,……………..seg_reg:Reg_name Where ASSUME is a assmebler directive Seg_reg is any of the segment register Seg_name is the name of an user defined segment Example: ASSUME CS: code segment, DS: data segment

28. SEGMENT • Segment is used to indicate the beginning of the logical segment. • Segment follows the name of the segment • Segment &ends must be enclosed the segment data, code ,extra or stack of the program. • General form: segment_name SEGMENT [WORD /PUBLIC] • WORD indicates that the segment has to be located at the next available address. • PUBLIC indicates that the given segment which have the same name.

29. Example: code segment ……………… ………………. code ends Data segment ………………. ……………… Data endsaa

30. ENDS:end of the segment • ENDS  informs the assembler the end of the segment • ENDS & SEGMENTmust enclosed the segment data or code of the program. • General form: segment_name ENDS Example: my_data segment ……….. My_data ENDS

31. END:end of the program • END to inform assembler the end of the program. • General form: END[start_address] • start_address indicates the location in the code segment where execution is to begin.

32. .CODE:simplified CODE segment directive • This simplified segment directive defines the code segment. • All executable code must be placed in this segment. • General form: .CODE [name]

33. .DATA:simplified DATA segment directive • This simplified segment directive defines the data segment for initialized near data • All data definition & decalration must be placed in this segment. • General form: .DATA

34. .STACK : simplified STACK segment directive • It defines the stack segment & default size of the stack is 1024 bytes which you may override. • General form: .STACK 100

35. .MODEL: memory model decalration for segment • It creates default segment. • General form: .MODEL memory_small Memory model: • TINY=masm 6.0 used for .com program • SMALL= all data in one segmetn & all code in one segment. • LARGE=both data &code in more than one segment

36. Value returning attribute directives 1) LENGTH: • The Lengthinforms the assemblers about the number of the elements in a data items such as array • If the array is defined in DB it return number of bytes allocated to a variable. • It the array is defined in DW it return the number of word allocated to the array variable.

37. General form: LENGTH variable_name Example: MOV CX,LENGTH NAME

38. SIZE • It is same as LENGTH except that it return the number of bytes allocated to the data items instead of the number of element in it • General form: SIZE variable_name Example: MOV AX, SIZE NAME

39. SEG:segment • The SEG is used to determine the segment in which the specified data items is defined • General form: SEG variable_name Example: MOV DS,SEG MSG For more detail contact us