Microprocessor Programming (Code :- 314321)

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MICROPROCESSOR PROGRAMMING (314321)

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Microprocessor Programming (Code :- 314321) 

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Unit 1 :- 8086 16-bit Microprocessor

Unit 2 :- The Art of assembly Language Programming 

Unit 3 :- Instruction Set of 8086 Microprocessor

Unit 4 :- 8086 Assembly Language Programming

Unit 5 :- Procedure and Macro in Assembly Language Program 

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Some Notes on 8086 Microprocessor 

BHE :- Bus High Enable it is available at pin 34. It is used to indicate transfer of data bus D8 to D15. This signal is low active during first clock cycle and thereafter it becomes active.

ALE :- ALE stands for address latch enable as address and data bus both are multiplexed, ALE is used to lock either address or data.

The fetching of next instruction while current instruction is being executed is known as Pipelining. Pipelining as become possible due to because of queue. BIU (Bus interface unit ) starts filling the queue until the entire queue is full. BIU restarts the filling queue when at least last two places are vacant.

Ready is used as acknowledgement signal from slower I/O device. When device is ready to transfer data then Ready is Active High signal. It is available at pin 22.

The Single Stepping or Tracing is done using Trap Flag Register. Trap Flag Register is also known as Control Flag Register. When TF=1 then Processor perform Single step i.e. it execute single line. Single Step mode is known as Executing a one line at a time. 

Debugger is program is extension of single step mode under the user control.

8086 supports memory segmentation. 8086 supports pipelining method. So it will increase the speed of execution of program. 

Ready : It is used as acknowledgement from slower I/O device or memory. It is Active high signal, when high; it indicates that the peripheral device is ready to transfer data. 

INTR :- This is a level triggered interrupt request input, checked during last clock cycle of each instruction to determine the availability of request. If any interrupt request is occurred, the processor enters the interrupt acknowledge cycle.

Flag register of 8086 

• Carry Flag :-  It is set when the carry / borrow is generated out of MSB of result (i.e. D7 for 8-bit 

operation and D15 for 16-bit operation ). Carry flag shows status of carry. When CF =0 then No 

carry generated and when CF =1 then carry is generated of MSB. Carry flag (CF) is at D0 . 

• Parity Flag :- It is set to 1 if the lower byte of result contains even number of 1’s otherwise it is 

set to reset i.e. 0. Parity Flag (PF) is at D2 . When PF=0 then Odd Parity and when PF=1 then Even 

Parity. 

• Auxiliary Flag :- It is set to 1 if the carry generated from lower nibble to higher nibble otherwise 

it is reset i.e. 0. Auxiliary Flag (AF) is at D4 . It is applicable at 8-bit instructions. 

• Zero Flag :- It is set to 1 if the result after performing ALU operations is zero otherwise it is reset. 

Zero Flag (ZF) is available at D6 .  

• Sign Flag :- It is set to 1 if the MSB of the result is 1 otherwise it is reset. Sign Flag is available at 

D7 . If SF=1 then it indicates that number is negative and SF=0 then it indicates that number is 

positive. It is applicable for signed operations.  

Practical Programs :- 

Write a program to perform addition of two 8 bit numbers 

include 'emu8086.inc' .model small .data     num db 12h .code     mov ax,@data     mov ds,ax     mov al,num     mov ah,13h     add ah,al      mov ah,4CH     INT 21h   ENDS

Write an ALP to perform addition of two 16 bit numbers.

include 'emu8086.inc' .model small .data     num1 dw 6753h     num2 dw 2020h     sum dw ? .code     mov ax,@data     mov ds,ax     mov ax,num1     mov bx,num2     add ax,bx     mov sum,ax     mov ah,4ch     int 21h  ends

Write an ALP to perform subtraction of two 8 bit numbers.

include 'emu8086.inc' .model small .data     a db 52h     b db 12h     c db ? .code     mov ax,@data     mov ds,ax     mov al,a     mov bl,b     sub al,bl     mov c,al     mov ah,4ch     int 21h ends

Write an ALP to perform subtraction of two 16 bit numbers.

include 'emu8086.inc' .model small .data     a dw 0081h     b dw 0011h     c dw ? .code     mov ax,@data     mov ds,ax     mov ax,a     mov bx,b     sub ax,bx     mov c,ax     mov ah,4ch     int 21h ends

Write an ALP to perform multiplication of two 8 bit numbers.

include 'emu8086.inc' .model small .data     a db 02h     b db 03h     c dw ? .code     mov ax,@data     mov ds,ax     mov al,a     mov bl,b     mul bl     mov c,ax     mov ah,4ch     int 21h ends

1.     1. ALP to perform addition and subtraction of two given numbers.

include 'emu8086.inc' .model small .data     a db 01h     b db 02h     c db 03h     d db 04h      e db ?     f db ? .code     mov ax,@data     mov ds,ax     mov al,a     mov bl,b     add al,bl     mov e,al     mov al,d     mov bl,c     sub al,bl     mov f,al     mov ah,4ch     int 21h ends

 

2.     2. ALP to find largest and smallest number from array of numbers.

include 'emu8086' .model small .stack 100h .data     ARRAY DB 15H,45H,08H,56H,78H     LARGEST DB 00H     small db 00h .code     MOV DX,DATA     MOV DS,DX     MOV CX,04H     MOV SI,OFFSET ARRAY     MOV AL,[SI]         smallest:     UP1: INC SI     CMP AL,[SI]     JC NEXT1     MOV AL,[SI]     NEXT1: DEC CX           JNZ UP1           MOV SMALL,AL                     MOV CX,04H     MOV DI,OFFSET ARRAY     MOV AL,[DI]         Large:        UP: INC DI     CMP AL,[DI]     JNC NEXT     MOV AL,[DI]     NEXT: DEC CX     JNZ UP     MOV LARGEST,AL     INT 21H ENDS

3.     

        3. ALP to find the length of string and concatenate two strings.

include 'emu8086.inc' .model small .data     msg db 'computer$'     count db ?      str1 db 'hello$'     str2 db 'world$'     .code     mov ax,@data     mov ds,ax          length:     mov si,offset msg     next1:         mov al,[si]         cmp al,'$'         je exit2             inc count             inc si             jmp next1     exit2:         mov dh,count              concat:         mov si,offset str1         next:             mov al,[si]             cmp al,'$'             je exit:             inc si             jmp next         exit:             mov di,offset str2         up:             mov al,[di]             cmp al,'$'             je exit1             mov [si],al             inc si             inc di             jmp up         exit1:             mov al,'$'             mov [si],al             mov ah,4ch         int 21h ends

 

4.     4. ALP to check a given number is odd or even

; Program to find number is odd or even include 'emu8086.inc' .MODEL SMALL .STACK 100H .DATA     MSG1 DB "ODD$"     MSG2 DB "EVEN$"     NUM DB ?   .CODE    MOV AX , @DATA     MOV DS , AX      MOV AH , 1h         INT 21H    MOV NUM , AL         ROR AL , 1         JC EL               LEA DX , MSG2      JMP EXIT        EL:     LEA DX , MSG1    EXIT:    MOV AH , 09H       INT 21H      MOV AH , 4CH       INT 21H ENDS

 

5.    5. ALP for multiplication of two signed and unsigned numbers.

include 'emu8086.inc' .model small .data     a db 02h     b db 04h     c db -03h     d db -05h     sign dw ?     unsign dw ? .code     mov ax,@data     mov ds,ax     mov al,a     mov bl,b     mul bl     mov unsign,ax     mov al,d     mov bl,c     imul bl     mov sign,ax     mov ah,4ch     int 21h end ends

 

6.     6. ALP to perform division of two unsigned and signed numbers.

include 'emu8086.inc' .model small .data     unsign db ?     sign db ? .code     mov ax,@data     mov ds,ax         mov ax,203     mov bl,4     div bl     mov unsign,al                  mov ax,-203     mov bl,4     idiv bl     mov sign,al         mov ah,4ch     int 21h end ends

 

7.     7. ALP to find sum of series.

include 'emu8086.inc' .model small .data     a db 1,2,3,4,5,6,7,8,9,10     sum db ? .code             mov ax,data         mov ds,ax         mov cl,10         lea bx,a         mov ah,00         mov al,00              l1:         add al,byte ptr[bx]         inc bx         dec cl         cmp cl,00         jnz l1         mov sum,al         mov ah,4ch         int 21h end ends

 

8.     8. ALP for string operations such as string reverse and string copy.

include 'emu8086.inc' .model small .data     STRING DB "STUPID$"     ARR DB 10 DUP('$')     destination DB 20 DUP(0) .code     MOV DX,@DATA     MOV DS,DX         copystring:     LEA SI,STRING     LEA DI,destination     mov cx,7     mov al,0     copyloop:         mov al,[si]         mov [di],al         inc si         inc di         dec cx         cmp cx,0         jnz copyloop         mov ah,09h         lea dx,destination     reversestring:     MOV CL,00H     LEA SI,STRING     MOV BL,'$' AGAIN: MOV AL,[SI]        CMP AL,BL        JZ REVERSE        INC CL        INC SI        JMP AGAIN REVERSE: LEA DI,ARR          DEC SI UP: MOV AL,[SI]     MOV [DI],AL     INC DI     DEC SI     LOOP UP     MOV [DI],'$'     LEA DX,ARR     MOV AH,09H     INT 21H     MOV AH,4CH     INT 21H end ends

 

9.     9. ALP to check a given number is odd or even

include 'emu8086.inc' .MODEL SMALL .STACK 100H .DATA     MSG1 DB "ODD$"     MSG2 DB "EVEN$"     NUM DB ?   .CODE    MOV AX , @DATA     MOV DS , AX      MOV AH , 1h         INT 21H    MOV NUM , AL       ROR AL , 1         JC EL               LEA DX , MSG2      JMP EXIT        EL:     LEA DX , MSG1    EXIT:    MOV AH , 09H       INT 21H    MOV AH , 4CH       INT 21H ENDS

 

10  10. ALP to perform arithmetic operations on given numbers using procedure                     Z=(A+B)*(C+D)

include 'emu8086.inc' .MODEL SMALL .STACK 100H .DATA    A DB 2    B DB 2    C DB 4    D DB 4    Z DW ?    RES DB ? .CODE   MOV AX , @DATA   MOV DS , AX     MOV AL , A   MOV AH , B     CALL ADD_BYTE   MOV RES , AL   ; STORING RESULT OF A+B     MOV AL , C   MOV AH , D     CALL ADD_BYTE   MOV BL , RES     MUL BL   AAM          ; ASCII ADJUST AFTER MULTIPLICATION     MOV Z , AX     ; PRINTING RESULT   MOV BH , AL   MOV DL , AH      ADD DL , 48   MOV AH , 02   INT 21H     MOV DH , 00   MOV DL , BH   ADD DL , 48   MOV AH , 02   INT 21H    MOV AH , 4CH  ; Service Routine for exit  INT 21H     ; Creating Procedure   ADD_BYTE PROC      ADD AL , AH      RET   ENDP END

 

11   11. ALP to perform arithmetic operations on given numbers using macro for equation    P=(X2+Y2)

.MODEL SMALL PROG MACRO a,b     MOV al,a     MUL al     MOV bl,al     MOV al,b     MUL al     ADD al,bl ENDM .DATA     x DB 02H     y DB 03H     p DB ? .CODE       MOV ax,data     MOV ds,ax     PROG x, y     MOV p,al     MOV ah,4Ch     int 21H END

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