Electronics at your Doorstep: A 4 digit calculator using 8086 microprocessor.....

A 4 digit calculator using 8086 microprocessor.....

circuit diagram.

Download programs required for various programmable chips from below...

7seg.h

/* 7-seg LED driver routines and defines */

/* Defines To Be Changed According To The Current Schematic */

// Comment following line if common cathode (non inverted), and uncomment if common cathode (inverted).

//#define LED_INVERT 1

// Digits positions

#ifndef LED_SEG_POS_A

#define LED_SEG_POS_A 0

#define LED_SEG_POS_B 1

#define LED_SEG_POS_C 2

#define LED_SEG_POS_D 3

#define LED_SEG_POS_E 4

#define LED_SEG_POS_F 5

#define LED_SEG_POS_G 6

#define LED_SEG_POS_H 7

#endif

/* Non-changeable Defines */

#ifndef LED_INVERT

#define LED_INVERT 0

#endif

#if LED_INVERT

#define LED_OPER &

#define LED_INV ~

#define LED_INIT_VAL 0xFF

#define LED_SEG_VAL(seg_pos) (0xFF & ~(1 << seg_pos))

#else

#define LED_OPER |

#define LED_INV

#define LED_INIT_VAL 0x00

#define LED_SEG_VAL(seg_pos) (1 << seg_pos)

#endif

#define LED_SEG_A LED_SEG_VAL(LED_SEG_POS_A)

#define LED_SEG_B LED_SEG_VAL(LED_SEG_POS_B)

#define LED_SEG_C LED_SEG_VAL(LED_SEG_POS_C)

#define LED_SEG_D LED_SEG_VAL(LED_SEG_POS_D)

#define LED_SEG_E LED_SEG_VAL(LED_SEG_POS_E)

#define LED_SEG_F LED_SEG_VAL(LED_SEG_POS_F)

#define LED_SEG_G LED_SEG_VAL(LED_SEG_POS_G)

#define LED_SEG_H LED_SEG_VAL(LED_SEG_POS_H)

/* Output bytes for diffirent numbers */

#define LED_SIGN_0 (LED_INIT_VAL LED_OPER LED_SEG_A LED_OPER LED_SEG_B LED_OPER LED_SEG_C LED_OPER LED_SEG_D LED_OPER LED_SEG_E LED_OPER LED_SEG_F)

#define LED_SIGN_1 (LED_INIT_VAL LED_OPER LED_SEG_B LED_OPER LED_SEG_C)

#define LED_SIGN_2 (LED_INIT_VAL LED_OPER LED_SEG_A LED_OPER LED_SEG_B LED_OPER LED_SEG_D LED_OPER LED_SEG_E LED_OPER LED_SEG_G)

#define LED_SIGN_3 (LED_INIT_VAL LED_OPER LED_SEG_A LED_OPER LED_SEG_B LED_OPER LED_SEG_C LED_OPER LED_SEG_D LED_OPER LED_SEG_G)

#define LED_SIGN_4 (LED_INIT_VAL LED_OPER LED_SEG_B LED_OPER LED_SEG_C LED_OPER LED_SEG_F LED_OPER LED_SEG_G)

#define LED_SIGN_5 (LED_INIT_VAL LED_OPER LED_SEG_A LED_OPER LED_SEG_C LED_OPER LED_SEG_D LED_OPER LED_SEG_F LED_OPER LED_SEG_G)

#define LED_SIGN_6 (LED_INIT_VAL LED_OPER LED_SEG_A LED_OPER LED_SEG_C LED_OPER LED_SEG_D LED_OPER LED_SEG_E LED_OPER LED_SEG_F LED_OPER LED_SEG_G)

#define LED_SIGN_7 (LED_INIT_VAL LED_OPER LED_SEG_A LED_OPER LED_SEG_B LED_OPER LED_SEG_C)

#define LED_SIGN_8 (LED_INIT_VAL LED_OPER LED_SEG_A LED_OPER LED_SEG_B LED_OPER LED_SEG_C LED_OPER LED_SEG_D LED_OPER LED_SEG_E LED_OPER LED_SEG_F LED_OPER LED_SEG_G)

#define LED_SIGN_9 (LED_INIT_VAL LED_OPER LED_SEG_A LED_OPER LED_SEG_B LED_OPER LED_SEG_C LED_OPER LED_SEG_D LED_OPER LED_SEG_F LED_OPER LED_SEG_G)

#define LED_SIGN_A (LED_INIT_VAL LED_OPER LED_SEG_A LED_OPER LED_SEG_B LED_OPER LED_SEG_C LED_OPER LED_SEG_E LED_OPER LED_SEG_F LED_OPER LED_SEG_G)

#define LED_SIGN_B (LED_INIT_VAL LED_OPER LED_SEG_C LED_OPER LED_SEG_D LED_OPER LED_SEG_E LED_OPER LED_SEG_F LED_OPER LED_SEG_G)

#define LED_SIGN_C (LED_INIT_VAL LED_OPER LED_SEG_A LED_OPER LED_SEG_D LED_OPER LED_SEG_E LED_OPER LED_SEG_F)

#define LED_SIGN_D (LED_INIT_VAL LED_OPER LED_SEG_B LED_OPER LED_SEG_C LED_OPER LED_SEG_D LED_OPER LED_SEG_E LED_OPER LED_SEG_G)

#define LED_SIGN_E (LED_INIT_VAL LED_OPER LED_SEG_A LED_OPER LED_SEG_D LED_OPER LED_SEG_E LED_OPER LED_SEG_F LED_OPER LED_SEG_G)

#define LED_SIGN_F (LED_INIT_VAL LED_OPER LED_SEG_A LED_OPER LED_SEG_E LED_OPER LED_SEG_F LED_OPER LED_SEG_G)

/* Encode one digit number into the output byte */

#define LED_ENCODE(value) \

(value & 0x08)? \

((value & 0x04)? \

((value & 0x02)? \

((value & 0x01)? \

(LED_SIGN_F): \

(LED_SIGN_E) \

): \

((value & 0x01)? \

(LED_SIGN_D): \

(LED_SIGN_C) \

) \

): \

((value & 0x02)? \

((value & 0x01)? \

(LED_SIGN_B): \

(LED_SIGN_A) \

): \

((value & 0x01)? \

(LED_SIGN_9): \

(LED_SIGN_8) \

) \

): \

((value & 0x04)? \

((value & 0x02)? \

((value & 0x01)? \

(LED_SIGN_7): \

(LED_SIGN_6) \

): \

((value & 0x01)? \

(LED_SIGN_5): \

(LED_SIGN_4) \

) \

): \

((value & 0x02)? \

((value & 0x01)? \

(LED_SIGN_3): \

(LED_SIGN_2) \

): \

((value & 0x01)? \

(LED_SIGN_1): \

(LED_SIGN_0) \

Board.c

#include "board.h"

#include "7seg.h"

void outp(unsigned int addr, char data)

// Output byte to port

{ __asm

{ mov dx, addr

mov al, data

out dx, al

}

char inp(unsigned int addr)

// Input byte from port

{ char result;

__asm

{ mov dx, addr

in al, dx

mov result, al

}

return result;

}

void set_int(unsigned char int_no, void * service_proc)

{ _asm

{ push es

xor ax, ax

mov es, ax

mov al, int_no

xor ah, ah

shl ax, 1

mov si, ax

mov ax, service_proc

mov es:[si], ax

inc si

mov bx, cs

mov es:[si], bx

pop es

}

/* USART */

unsigned char putch_buffer[256];

unsigned char putch_out_pos;

unsigned char putch_pos;

void putch_out(void)

// Output one symbol from buffer to 8251A USART

{ if (putch_out_pos == putch_pos)

return;

if((inp(ADR_USART_STAT) & 0x01) == 0)

return;

outp(ADR_USART_DATA, putch_buffer[putch_out_pos]);

putch_out_pos++;

}

unsigned char putch( unsigned char c )

// Put one symbol into buffer

{ putch_buffer[putch_pos] = c;

putch_pos++;

return c;

}

void prints(char* s)

// Print string using putch() function

{ char c;

while(s && *s)

{ c = *s;

if (c == '\r')

c = '\n';

putch(c);

s++;

}

void printui(unsigned int i)

// Print unsigned int using putch() function

{ unsigned char val;

unsigned int temp = 10000;

unsigned char printed=0;

while (temp >= 1)

{ val = (i / temp) % 10;

if ((val!=0) || printed || (temp == 1))

{ putch(val + '0');

printed = 1;

}

if (temp == 1)

break;

temp /= 10;

}

void setup_usart(void)

// 8251 USART Setup

{ /* setup USART */

outp(ADR_USART_CMD, 0x7D); /* ED */

outp(ADR_USART_CMD, 0x07); /* RxEn, TxEn, DTRa */

putch_out_pos = 0;

putch_pos = 0;

}

/* Timer */

signed char delay;

int sound_enabled;

int display_enabled;

void sound_nmi(void)

{ delay++;

if (delay >= 10)

delay = -delay;

outp(ADR_TIMER_CONTROL, TIMER_COUNTER2 | TIMER_MODE2 | TIMER_LSB);

outp(ADR_TIMER_DATA2, ABS(delay)+0x40);

}

void _interrupt _far nmi_handler(void);

void setup_nmi(void)

// Set NMI Timer at 50Hz.

{ set_int(0x02, (void *)&nmi_handler);

outp(ADR_TIMER_CONTROL, TIMER_COUNTER1 | TIMER_MODE2 | TIMER_LSB_MSB);

outp(ADR_TIMER_DATA1, 0xD0);

outp(ADR_TIMER_DATA1, 0x07);

}

/* PIO */

// Value to be displayed

unsigned int display_value;

// Current display position

unsigned char cur_display_pos;

// Current dispaly segments

unsigned char cur_display_segs;

unsigned char keys[16];

#define KEY_7 0

#define KEY_8 1

#define KEY_9 2

#define KEY_DIV 3

#define KEY_4 4

#define KEY_5 5

#define KEY_6 6

#define KEY_MUL 7

#define KEY_1 8

#define KEY_2 9

#define KEY_3 10

#define KEY_MIN 11

#define KEY_C 12

#define KEY_0 13

#define KEY_EQ 14

#define KEY_PLU 15

#define KEYBUFFERLEN 16

unsigned char keybuffer[KEYBUFFERLEN];

unsigned char keypos=0;

void process_key(unsigned char keycode)

{ if (keypos < KEYBUFFERLEN)

{ keybuffer[keypos] = keycode;

keypos++;

}

#define NUM_LED_DIGITS 4

unsigned char disp_buffer[4] = {LED_INIT_VAL, LED_INIT_VAL, LED_INIT_VAL, LED_INIT_VAL};

void display_nmi(void)

// Display And Keyboard Handler

{ unsigned int i;

unsigned int cur_key;

unsigned int keys_inp;

unsigned int out_value;

// Light Off All Digits

outp(ADR_PPI_PORTA, 0xFF);

// Output Segments Value

outp(ADR_PPI_PORTB, cur_display_segs);

// Light On Current Digit

outp(ADR_PPI_PORTA, 0xFF & ~(1 << cur_display_pos));

// Keyboard Input

keys_inp = inp(ADR_PPI_PORTC);

cur_key = (cur_display_pos * 4);

for (i=0; i<4; i++)

{ if (keys_inp & (1 << i))

keys[cur_key]=0;

else

{ if (!keys[cur_key])

{ process_key(cur_key);

keys[cur_key]=1;

}

cur_key++;

}

// Shift To The Next Digit

cur_display_pos++;

if (cur_display_pos > 3)

{ cur_display_pos = 0;

}

// Set Next Digit Value

cur_display_segs = disp_buffer[cur_display_pos];

}

void init_pio(void)

/* 8255A PIO Demo */

{ outp(ADR_PPI_CONTROL, PPI_PORTA_OUT | PPI_PORTB_OUT | PPI_PORTCL_INP | PPI_PORTCH_INP | PPI_MODE_BCL_0 | PPI_MODE_ACH_0 | PPI_ACTIVE);

display_value = 0;

cur_display_pos = 0;

cur_display_segs = 0xFF;

display_enabled = 1;

}

/* NMI Interrupt Handler */

void _interrupt _far nmi_handler(void)

{ if (sound_enabled)

sound_nmi();

if (display_enabled)

display_nmi();

putch_out();

}

/* Support functions */

void initialise(void)

{ sound_enabled = 0;

display_enabled = 0;

cur_display_segs = LED_INIT_VAL;

setup_nmi();

setup_usart();

init_pio();

}

char input ()

{ if (keypos > 0)

{ unsigned char head_key = keybuffer[0];

keypos--;

for (unsigned char i=0; i<keypos; i++)

keybuffer[i] = keybuffer[i+1];

switch (head_key)

{ case KEY_0:

return '0';

case KEY_1:

return '1';

case KEY_2:

return '2';

case KEY_3:

return '3';

case KEY_4:

return '4';

case KEY_5:

return '5';

case KEY_6:

return '6';

case KEY_7:

return '7';

case KEY_8:

return '8';

case KEY_9:

return '9';

case KEY_PLU:

return '+';

case KEY_MIN:

return '-';

case KEY_MUL:

return '*';

case KEY_DIV:

return '/';

case KEY_EQ:

return '=';

case KEY_C:

return 'C';

}

return 0;

}

char output(char ch)

{ putch(ch);

if (ch >= '0' && ch <= '9')

{ for (char i=0; i<NUM_LED_DIGITS-1; i++)

disp_buffer[i] = disp_buffer[i+1];

disp_buffer[NUM_LED_DIGITS-1] = LED_ENCODE(ch - '0');

}

return ch;

}

void clearscreen()

{ putch(13);

for (char i=0; i<NUM_LED_DIGITS; i++)

disp_buffer[i] = LED_INIT_VAL;

}

) \

)

Board.h

#ifndef _board_h_

#define _board_h_

/* 8086 Demo Board support functions and macros */

// Absolute value of an argument

#define ABS(a) ((a>=0)?a:-a)

// Set an Interrupt Handler

void set_int(unsigned char int_no, void * service_proc);

// I/O Ports input and output

void outp(unsigned int addr, char data);

char inp(unsigned int addr);

/* I/O Address Bus decode - every device gets 0x200 addresses */

#define IO0 0x0000

#define IO1 0x0200

#define IO2 0x0400

#define IO3 0x0600

#define IO4 0x0800

#define IO5 0x0A00

#define IO6 0x0C00

#define IO7 0x0E00

#define IO8 0x1000

#define IO9 0x1200

#define IO10 0x1400

#define IO11 0x1600

#define IO12 0x1800

#define IO13 0x1A00

#define IO14 0x1C00

#define IO15 0x1E00

/* 8251A USART */

#define ADR_USART_DATA (IO0 + 0x00)

#define ADR_USART_CMD (IO0 + 0x02)

#define ADR_USART_STAT ADR_USART_CMD

/* 8253A Timer */

#define ADR_TIMER_CONTROL (IO2 + 0x06)

#define ADR_TIMER_DATA0 (IO2 + 0x00)

#define ADR_TIMER_DATA1 (IO2 + 0x02)

#define ADR_TIMER_DATA2 (IO2 + 0x04)

#define TIMER_COUNTER0 0x00

#define TIMER_COUNTER1 0x40

#define TIMER_COUNTER2 0x80

#define TIMER_LATCH 0x00

#define TIMER_LSB 0x10

#define TIMER_MSB 0x20

#define TIMER_LSB_MSB 0x30

#define TIMER_MODE0 0x00

#define TIMER_MODE1 0x02

#define TIMER_MODE2 0x04

#define TIMER_MODE3 0x06

#define TIMER_MODE4 0x08

#define TIMER_MODE5 0x09

#define TIMER_BCD 0x01

/* 8255A PIO */

#define ADR_PPI_PORTA (IO1)

#define ADR_PPI_PORTB (IO1 + 0x02)

#define ADR_PPI_PORTC (IO1 + 0x04)

#define ADR_PPI_CONTROL (IO1 + 0x06)

#define PPI_PORTA_INP 0x10

#define PPI_PORTA_OUT 0x00

#define PPI_PORTB_INP 0x02

#define PPI_PORTB_OUT 0x00

#define PPI_PORTCL_INP 0x01

#define PPI_PORTCL_OUT 0x00

#define PPI_PORTCH_INP 0x08

#define PPI_PORTCH_OUT 0x00

#define PPI_MODE_BCL_0 0x00

#define PPI_MODE_BCL_1 0x04

#define PPI_MODE_ACH_0 0x00

#define PPI_MODE_ACH_1 0x20

#define PPI_MODE_ACH_2 0x40

#define PPI_ACTIVE 0x80

#endif

Calc.c

************ Integer Calculator ( 2K Code Limit) ************

*******************************************************************************/

#include "calc.h"

//Variables

static LONG lvalue;

static LONG rvalue;

static CHAR currtoken;

static CHAR lasttoken;

static CHAR lastpress;

static CHAR outputbuffer[MAX_DISPLAY_CHAR];

VOID main (VOID)

//Initialise our variables and call the

//Assembly routine to initialise the LCD display.

{ lvalue = 0;

rvalue = 0;

currtoken = '=';

lasttoken = '0';

initialise(); // Initialize the LCD

calc_output(OK);

calc_evaluate();

}

VOID calc_evaluate()

{ CHAR key;

INT i;

CHAR number[MAX_DISPLAY_CHAR];

CHAR *bufferptr;

// Clear the buffer before we start.

for (i = 0; i <= MAX_DISPLAY_CHAR; i++)

{ number[i] = ' ';

}

bufferptr = number;

for (;;)

{ key = calc_getkey();

if (calc_testkey(key))

// Key test positive for digit so we read it into the

// buffer and then write the buffer to the screen/LCD.

// Size limit the number of digits - allow for termination

// and possible negative results.

{ if (bufferptr != &number[MAX_DISPLAY_CHAR - 2])

{ *bufferptr = key;

calc_display(number);

bufferptr++;

}

else

// Key is an operator so pass it to the function handlers.

// If we are just after startup or cancel then assign to lvalue

// otherwise assign to rvalue.

{

//Assign the value.

if (lasttoken == '0')

{ lvalue = calc_asciidec (number);}

else

{ rvalue = calc_asciidec (number);}

//Clear the number buffer.

bufferptr = number;

for (i = 0;i <= MAX_DISPLAY_CHAR; i++)

{ number[i] = ' '; }

//Process the Operator.

currtoken = key;

if (currtoken == 'C')

{ calc_opfunctions(currtoken); }

else

{ calc_opfunctions(lasttoken); }

// Clear the outputbuffer for reuse on next operation.

for (i = 0;i <= MAX_DISPLAY_CHAR;i++)

{ outputbuffer[i] = ' ';}

bufferptr = number;

// Handle the equals operation here for brevity.

// All we need do is preserve the previous operator in

// lasttoken.

if (currtoken != 0x3D) lasttoken = currtoken;

}

lastpress = key;

}

VOID calc_opfunctions (CHAR token)

// Handle the operations. Lvalue holds the result and we test for

// consecutive operator presses.

{ CHAR result;

switch(token)

// Add.

{ case '+' : if ((currtoken == '=' ) || ((lastpress >= 0x30) && (lastpress <=0x39)))

{ lvalue += rvalue;

result = calc_chkerror(lvalue);

}

else

{ result = SLEEP; } break;

// Subtract.

case '-' : if ((currtoken == '=' ) || ((lastpress >= 0x30) && (lastpress <=0x39)))

{ lvalue -= rvalue;

result = calc_chkerror(lvalue);

}

else

{ result = SLEEP;} break;

// Multiply.

case '*' : if ((currtoken == '=' ) || ((lastpress >= 0x30) && (lastpress <=0x39)))

{ lvalue *= rvalue;

result = calc_chkerror(lvalue);

}

else

{ result = SLEEP;} break;

// Divide.

case '/' : if ((currtoken == '=' ) || ((lastpress >= 0x30) && (lastpress <=0x39)))

{ if (rvalue)

{ lvalue /= rvalue;

result = calc_chkerror(lvalue);

}

else

{ result = ERROR;}

}

else

{ result = SLEEP;} break;

// Cancel.

case 'C' : lvalue = 0;

rvalue = 0;

currtoken = '0';

lasttoken = '0';

result = OK; break;

default : result = SLEEP;

}

calc_output(result);

}

/************************************************************************

***** Utility Routines *****

***************************/

INT calc_chkerror (LONG num)

// Check upper and lower bounds for the display.

// i.e. 99999999 and -99999999.

{ if ((num >= -9999999) && (num <= 9999999))

return OK;

else

return ERROR;

}

VOID calc_output (INT status)

// Output according to the status of the operation.

// *Sleep* is used for the first op press after a full cancel

// or on startup.

{ switch (status)

{ case OK : calc_display(calc_decascii(lvalue)); break;

case SLEEP : break;

case ERROR : calc_display("Exception "); break;

default : calc_display("Exception "); break;

}

LONG calc_asciidec (CHAR *buffer)

// Convert the ASCII string into the floating point number.

{ LONG value;

LONG digit;

value = 0;

while (*buffer != ' ')

{ digit = *buffer - 48;

value = value*10 + digit;

buffer++;

}

return value;

}

CHAR *calc_decascii (LONG num)

// A rather messy function to convert a floating

// point number into an ASCII string.

{ LONG temp = num;

CHAR *arrayptr = &outputbuffer[MAX_DISPLAY_CHAR];

LONG divisor = 10;

LONG result;

CHAR remainder,asciival;

INT i;

// If the result of the calculation is zero

// insert a zero in the buffer and finish.

if (!temp)

{ *arrayptr = 48;

goto done;

}

// Handle Negative Numbers.

if (temp < 0)

{ outputbuffer[0] = '-';

temp -= 2*temp;

}

for (i=0 ; i < sizeof(outputbuffer) ; i++)

{ remainder = temp % divisor;

result = temp / divisor;

// If we run off the end of the number insert a space into

// the buffer.

if ((!remainder) && (!result))

{ *arrayptr = ' ';}

// We're in business - store the digit offsetting

// by 48 decimal to account for the ascii value.

else

{ asciival = remainder + 48;

*arrayptr = asciival;

}

temp /= 10;

// Save a place for a negative sign.

if (arrayptr != &outputbuffer[1]) arrayptr--;

}

done: return outputbuffer;

}

CHAR calc_testkey (CHAR key)

// Test whether the key is a digit or an operator. Return 1 for digit, 0 for op.

{ if ((key >= 0x30) && (key <= 0x39))

{ return 1;}

else

{ return 0;}

}

/************************************************************************

***** I/O Routines *****

***********************/

CHAR calc_getkey (VOID)

// Use the input routine from the *Keypad_Read* assembly file to

// Scan for a key and return ASCII value of the Key pressed.

{ CHAR mykey;

do mykey = input();

while (mykey == 0);

return mykey;

}

VOID calc_display (CHAR buf[MAX_DISPLAY_CHAR])

// Use the Output and Clearscreen routines from the

// *LCD_Write* assembly file to output ASCII values to the LCD.

{ INT i = 0;

clearscreen();

for (i = 0 ; i <= MAX_DISPLAY_CHAR ; i++)

{ if (buf[i] != ' ')

{ output(buf[i]); }

}

Cal.h

************ Integer Calculator ( 2K Code Limit) ************

********************************************************************************/

typedef void VOID;

typedef int INT;

typedef unsigned short WORD;

typedef char CHAR;

typedef unsigned char BYTE;

typedef float FLOAT;

typedef double DOUBLE;

typedef long LONG;

// Define the maximum number of ASCII characters that can fit

// on the display.

#define MAX_DISPLAY_CHAR 9

//Error handling status.

enum ERROR { OK = 0, SLEEP = 1, ERROR = 2};

/************************************************************************

***** FUNCTION PROTOTYPES *****

******************************/

VOID calc_evaluate();

//Operator indirect function.

VOID calc_opfunctions (CHAR token);

//Utility functions.

CHAR calc_testkey (CHAR ch);

LONG calc_asciidec (CHAR *buffer);

CHAR *calc_decascii (LONG num);

INT calc_chkerror (LONG num);

VOID calc_output (INT status);

// I/O functions.

CHAR calc_getkey (VOID);

VOID calc_display (CHAR buf[MAX_DISPLAY_CHAR]);

//Assembly Function prototypes.

void initialise();

char input ();

char output(char ch);

void clearscreen();

Rt.asm

.MODEL SMALL

.8086

.code

extrn _main:proc

.startup

call near ptr _main

endless:

jmp endless

.data

public __acrtused ; trick to force in startup

__acrtused = 9876h ; funny value not easily matched in SYMDEB

.stack

END

2 comments:

Flamelight146666 February 2019 at 18:10
I have a few doubts regarding the circuit. Please email me your contact info, if possible. Here's my email id: flamelight14666@gmail.com
12345678923 October 2019 at 06:39
It is rather very good, nevertheless glance at the data with this handle. 48 inches in feet

Electronics at your Doorstep

Friday, 4 April 2014

A 4 digit calculator using 8086 microprocessor.....

2 comments:

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