While high-level languages like C++ are well known for abstracting away low-level operations, sometimes it’s beneficial to peek under the hood to see how things really work at the machine level. In this post, we’ll explore a simple C++ program that incorporates inline assembly to add two 16-bit numbers.
#include<iostream.h>
#include<conio.h>
#include<stdio.h>
void main()
{
clrscr();
int a,b,c;
cout<<"Enter First Number:";
cin>>a;
cout<<"Enter Second Number:";
cin>>b;
asm mov ax, a // Move first number into AX
asm mov bx, b // Move second number into BX
asm add ax, bx // Add BX to AX (binary addition)
asm mov c, ax // Move result into variable 'c'
cout<<"Result:";
cout<<c;
getch();
}
While high-level programming languages like C++ make arithmetic operations incredibly simple, delving into inline assembly offers valuable insights into how the CPU processes instructions under the hood. Hence in this post, we’ll walk through a simple program that uses both C++ and inline assembly to add two integer values. Additionally, we will carry out decimal adjust after addition.
While modern high-level languages like C++ abstract away many low-level operations, sometimes it’s useful to dive into assembly-level instructions for greater control and understanding. This example demonstrates subtraction using inline assembly in C++, with the addition of the DAS instruction to adjust the result for Binary Coded Decimal (BCD) operations.
#include<iostream.h>
#include<conio.h>
#include<stdio.h>
void main() {
clrscr();
int a, b, c;
cout << "Enter First Number:";
cin >> a;
cout << "Enter Second Number:";
cin >> b;
asm mov ax, a // Move 'a' into AX
asm mov bx, b // Move 'b' into BX
asm sub ax, bx // Subtract BX from AX
asm das // Adjust AX for BCD subtraction
asm mov c, ax // Store result in 'c'
cout << "Result:";
cout << c;
getch();
}
While modern high-level languages like C++ abstract away many low-level operations, sometimes it’s useful to get closer to the hardware to understand how things work under the hood. This example demonstrates how to subtract two 16-bit numbers using inline assembly in a simple C++ program.
#include<iostream.h>
#include<conio.h>
#include<stdio.h>
void main() {
clrscr();
int a, b, c;
cout << "Enter First Number:";
cin >> a;
cout << "Enter Second Number:";
cin >> b;
asm mov ax, a // Move 'a' into AX
asm mov bx, b // Move 'b' into BX
asm sub ax, bx // Subtract BX from AX
asm mov c, ax // Store result in 'c'
cout << "Result:";
cout << c;
getch();
}
This blog post will guide you through a C++ program that performs the addition of two numbers using inline assembly. While modern compilers provide high-level arithmetic operations, understanding inline assembly can help in optimizing performance and understanding low-level interactions with the CPU. Let’s explore this step-by-step!
#include<iostream.h>
#include<conio.h>
#include<stdio.h>
void main()
{
clrscr();
short int a, b, c;
cout << "Enter First Number: ";
cin >> a;
cout << "Enter Second Number: ";
cin >> b;
asm mov ax, a
asm mov ah, 00h
asm mov bx, b
asm mov bh, 00h
asm add al, bl
asm mov c, ax
cout << "Result: ";
cout << c;
getch();
}
In this blog post, we’ll explore how to reverse an array using an 8086 assembly language program. We will walk through the logic, the step-by-step execution, and provide a working code snippet to illustrate the process.
Overall Process:
The program initializes registers and sets up pointers to the source (ARR) and destination (REV_ARR) arrays.
It processes each element of the original array, copying it in reverse order to the destination array.
After processing all elements, the program terminates, leaving the reversed array in memory.
8086 Assembly Code:
DATA SEGMENT
STR1 DB 01H,02H,05H,03H,04H
STR2 DB 5 DUP(?)
DATA ENDS
CODE SEGMENT
ASSUME CS:CODE, DS:DATA
START:
MOV AX, DATA
MOV DS, AX
LEA SI, STR1
LEA DI, STR2+4
MOV CX, 05H
BACK: CLD
MOV AL, [SI]
MOV [DI], AL
INC SI
DEC DI
DEC CX
JNZ BACK
INT 3
CODE ENDS
END START
A palindrome is a word, phrase, or sequence that reads the same forward and backward. This 8086 assembly program determines whether a given string is a palindrome by reversing the string and comparing it to the original.
The program follows these steps:
Initialize the Data Segment: Load the string to be checked.
Reverse the String: Store the reversed string in another memory location.
Compare the Original and Reversed Strings: Use CMPSB to compare byte-by-byte.
Print the Result: Display whether the string is a palindrome or not.
