Added A3 code and updated link in README.

README file. (Thanks to Afan for the code 🙇)
(He made me add those credits)

Codes/Group A/Assignment-A1/Code-A1.py

@@ -0,0 +1,109 @@
+# Assignment-A1
+
+try:
+    source = open('source.txt','r')
+    data = source.read()
+    print('File read successfully\n\n')
+    source.seek(0)
+except FileNotFoundError: #A little bit of exception handling
+    print('\n\n\nFile Not found. Create a source.txt first.\n\n\n ')
+except IOError:
+    print('There was an IO error')
+LT_index = 0 #index of LT table
+ST_index = 0 #index of ST table
+add = 0 # address in source code
+MOT = {'STOP': '00','ADD': '01','SUB': '02','MULT': '03','MOVER': '04','MOVEM': '05','COMP': '06','BC': '07','DIV': '08','READ': '09','PRINT': '10','START': '01','END': '02','ORIGIN': '03','LTORG': '05','DS': '01','DC': '02','AREG,': '01','BREG,': '02','EQ':'01'}
+ST = []
+code=[]
+LT=[]
+MC = []
+# LT, ST are lists of lists. code= intermediate code table
+
+
+def classy(text):
+    '''This function will return the class of the word to be inputted in the Intermediate table'''
+    text = text.upper()
+    if text in ['STOP','ADD','SUB', 'MULT','MOVER','MOVEM','COMP','BC','DIV','READ', 'PRINT']:
+        return 'IS'
+    elif text in ['START','END','ORIGIN','LTORG']:
+        return 'AD'
+    elif text in ['DS','DC']:
+        return 'DL'
+    elif text in ['AREG,','BREG,']: return 'RG'
+    elif text in ['EQ']: return 'CC'
+    else: return 'None'
+
+def handle_start():
+    '''This function gives you the starting address of the code'''
+    line= source.readline()
+    words=line.split()
+    if words[0].upper()=='START':
+        return int(words[1])
+    else: 
+        print("No Start Statement! Abort!\n")
+        return 0
+
+def pass1():
+    add=handle_start()
+    if not add:
+        print("Ending Pass 1 due to Above error.")
+        return
+    global ST_index, LT_index  # to modify global variables, use global keyword
+    while True:
+        line=source.readline()# handlestart function reads line 1 and we start from the second line.
+        if not line:
+            break
+        words= line.split()
+        for w in words:
+            w=w.upper()
+            if w[0]=='=':
+                entry=[LT_index,w, add]
+                LT.append(entry)
+                LT_index +=1 
+            elif classy(w)== 'None':
+                for term in ST:
+                    if w== term[1]: break # I check if the label is already present in ST.
+                else:
+                    entry=[ST_index,w, add]
+                    ST.append(entry)
+                    ST_index +=1
+        add+=1
+    print('LT:')
+    for a in LT:
+        print(a)
+    print('\n\n\nST:')
+    for a in ST:
+        print(a)
+        
+def intermediate():
+    source.seek(0)
+    while True:
+        entry=[]
+        ind = 0
+        line=source.readline()
+        if not line:
+            break
+        words=line.split()
+        for w in words:
+            w=w.upper()
+            if classy(w)!='None': #it is a directive
+                entry.append((classy(w),MOT[w]))
+            elif w[0]== '=': #it is a literal.
+                for a in LT:
+                    if a[1]==w:
+                        ind = a[0]
+                        break
+                entry.append(('L',ind))
+            else: #it is a symbol
+                for a in ST:
+                    if a[1]==w:
+                        ind = a[0]
+                        break
+                entry.append(('S',ind))
+        code.append(entry)
+    print("\nThe Intermediate code is:")
+    for entry in code:
+        print(entry)
+
+pass1()
+intermediate()

Codes/Group A/Assignment-A1/source.txt

@@ -0,0 +1,4 @@
+Start 100
+Label MOVER AREG, =5
+add areg, =999
+sub breg, x

Codes/Group A/Assignment-A3/A3.c

@@ -0,0 +1,32 @@
+#include <jni.h>
+#include <stdio.h>
+#include "A3.h"
+
+JNIEXPORT jint JNICALL Java_A3_add(JNIEnv *env, jobject obj, jint a, jint b) {
+    jint result = a + b;
+    printf("\n%d + %d = %d\n", a, b, result);
+    return result; // Return the result
+}
+
+JNIEXPORT jint JNICALL Java_A3_sub(JNIEnv *env, jobject obj, jint a, jint b) {
+    jint result = a - b;
+    printf("\n%d - %d = %d\n", a, b, result);
+    return result; // Return the result
+}
+
+JNIEXPORT jint JNICALL Java_A3_mult(JNIEnv *env, jobject obj, jint a, jint b) {
+    jint result = a * b;
+    printf("\n%d * %d = %d\n", a, b, result);
+    return result; // Return the result
+}
+
+JNIEXPORT jint JNICALL Java_A3_div(JNIEnv *env, jobject obj, jint a, jint b) {
+    if (b == 0) {
+        printf("Error: Division by zero.\n");
+        return 0; // Return 0 or handle error appropriately
+    }
+    jint result = a / b;
+    printf("\n%d / %d = %d\n", a, b, result);
+    return result; // Return the result
+}
+

Codes/Group A/Assignment-A3/A3.java

@@ -0,0 +1,45 @@
+import java.io.*;
+import java.util.*;
+
+class A3 {
+    static {
+        System.loadLibrary("A3");
+    }
+
+    private native int add(int a, int b);
+    private native int sub(int a, int b);
+    private native int mult(int a, int b);
+    private native int div(int a, int b);
+
+    public static void main(String[] args) {
+        Scanner sc = new Scanner(System.in);
+        int a, b, ch;
+
+        System.out.println("\nEnter value of a : ");
+        a = sc.nextInt();
+        System.out.println("\nEnter value of b : ");
+        b = sc.nextInt();
+
+        do {
+            System.out.println("\nENTER YOUR CHOICE : ");
+            ch = sc.nextInt();
+            switch (ch) {
+                case 1:
+                    new A3().add(a, b);
+                    break;
+                case 2:
+                    new A3().sub(a, b);
+                    break;
+                case 3:
+                    new A3().mult(a, b);
+                    break;
+                case 4:
+                    new A3().div(a, b);
+                    break;
+                default:
+                    System.out.println("Your choice is wrong.");
+            }
+        } while (ch < 5);
+    }
+}
+

Codes/Group A/Assignment-A3/README.md

@@ -0,0 +1,36 @@
+## Steps to run this code
+
+These are the steps to run code for Assignment-A3.
+
+---
+
+> [!IMPORTANT]
+> I've tested this on Linux, thus I've included instructions for the same.
+
+### Prerequisites
+
+1. open-jdk (version 11 or higher)
+2. gcc
+3. Common sense
+
+### Steps
+
+1. Compile `A3.java`:
+```shell
+javac A3.java
+```
+
+2. Generate header file:
+```shell
+javac -h . A3.java
+```
+
+3. Compile C code:
+```shell
+gcc -shared -o libA3.so -fPIC -I"$JAVA_HOME/include" -I"$JAVA_HOME/include/linux" A3.c
+```
+
+4. Run program:
+```shell
+java -Djava.library.path=. A3
+```

README.md

@@ -8,7 +8,11 @@ This repository serves as a comprehensive resource for the Systems Programming a
 
 ### Codes
 ##### Group A
+1. [Code-A1 - Pass 1](https://git.kska.io/sppu-te-comp-content/SystemsProgrammingAndOperatingSystem/src/branch/main/Codes/Group%20A/Assignment-A1)
+    - [Code](https://git.kska.io/sppu-te-comp-content/SystemsProgrammingAndOperatingSystem/src/branch/main/Codes/Group%20A/Assignment-A1/Code-A1.py)
+    - [Source file](https://git.kska.io/sppu-te-comp-content/SystemsProgrammingAndOperatingSystem/src/branch/main/Codes/Group%20A/Assignment-A1/source.txt)
 2. [Code-A2 - Pass 1 and Pass 2 of 2-Pass Macroprocessor](https://git.kska.io/sppu-te-comp-content/SystemsProgrammingAndOperatingSystem/src/branch/main/Codes/Group%20A/Code-A2.py)
+3. [Code-A3 - DLL](https://git.kska.io/sppu-te-comp-content/SystemsProgrammingAndOperatingSystem/src/branch/main/Codes/Group%20A/Assignment-A3/)
 
 ##### Group B
 5. [CPU Scheduling Algorithms: FCFS, SJF (Preemptive), Priority (Non-Preemptive) and Round Robin (Preemptive)](https://git.kska.io/sppu-te-comp-content/SystemsProgrammingAndOperatingSystem/src/branch/main/Codes/Group%20B/Assignment%20-%205)