add error message if no program selected

fix error with negative numbers

njvm.c

@@ -3,12 +3,11 @@
 #include "instruktion.c"
 #include "code.c"
 #include "stack.c"
-#include "program.c" 
+#include "program.c"
-
 
 //Comment to disable debug
 
-#define DEBUG
+//#define DEBUG
 
 // Stack
 struct stack stack;
@@ -33,48 +32,49 @@ void execute(struct program program) {
     for (i = 0; i < *program.size; ++i) {
         switch (program.program[i] >> 24) {
             case HALT:
-                  goto end;
+                goto end;
                 break;
             case PUSHC:
-                  push(stack,IMMEDIATE(program.program[i]));
+                push(stack, SIGN_EXTEND(IMMEDIATE(program.program[i])));
                 break;
             case ADD:
-                  push(stack,pop(stack)+pop(stack));
+                push(stack, pop(stack) + pop(stack));
                 break;
             case SUB:
-                  temp = pop(stack);
+                temp = pop(stack);
-                  push(stack,pop(stack) - temp);
+                push(stack, pop(stack) - temp);
                 break;
             case MUL:
-                  push(stack,pop(stack)*pop(stack));
+                push(stack, pop(stack) * pop(stack));
                 break;
             case DIV:
-                  temp = pop(stack);
+                temp = pop(stack);
-                  push(stack,pop(stack)/temp);
+                push(stack, pop(stack) / temp);
                 break;
             case MOD:
-                  temp = pop(stack);
+                temp = pop(stack);
-                  push(stack,pop(stack)%temp);
+                push(stack, pop(stack) % temp);
                 break;
             case RDINT:
-                  scanf("%i",&intInput);
+                scanf("%i", &intInput);
-                  push(stack,intInput);
+                push(stack, intInput);
                 break;
             case WRINT:
-                  printf("%i",pop(stack));
+                printf("%i", pop(stack));
                 break;
             case RDCHR:
-                  scanf("%c",&charInput);
+                scanf("%c", &charInput);
-                  push(stack,charInput);
+                push(stack, charInput);
                 break;
             case WRCHR:
-                  printf("%c",pop(stack));
+                printf("%c", pop(stack));
                 break;
         }
     }
     end:
     return;
 }
+
 #ifdef DEBUG
 
 void tests(void){
@@ -93,40 +93,47 @@ int main(int argc, char *argv[]) {
     stack.size = &size;
     stack.current = &current;
     stack.stack = s;
-     
+
     // Initialize ProgrammSpeicher
     int psize = 1000;
+    int saveProgram = 0;
     unsigned int p[1000];
     program.size = &psize;
     program.program = p;
+    program.saveProgram = &saveProgram;
 
-    
+
-    #ifdef DEBUG
+#ifdef DEBUG
-      tests();
+    tests();
-    #endif /* ifdef DEBUG */
+#endif /* ifdef DEBUG */
-     if (argc > 1) {
+    if (argc > 1) {
         if (strcmp(argv[1], "--version") == 0) {
             version();
         } else if (strcmp(argv[1], "--help") == 0) {
             help();
-        } else if (strcmp(argv[1], "--prog1") == 0) { 
+        } else if (strcmp(argv[1], "--prog1") == 0) {
-            copyToProgram(code1, sizeof(code1)/sizeof(code1[0]),program);
+            copyToProgram(code1, sizeof(code1) / sizeof(code1[0]), program);
             goto run;
-        } else if (strcmp(argv[1],"--prog2") == 0) {  
+        } else if (strcmp(argv[1], "--prog2") == 0) {
-            copyToProgram(code2, sizeof(code2)/sizeof(code2[0]),program);
+            copyToProgram(code2, sizeof(code2) / sizeof(code2[0]), program);
             goto run;
-        }else if (strcmp(argv[1],"--prog3") == 0) { 
+        } else if (strcmp(argv[1], "--prog3") == 0) {
-            copyToProgram(code3, sizeof(code3)/sizeof(code3[0]),program);
+            copyToProgram(code3, sizeof(code3) / sizeof(code3[0]), program);
             goto run;
-        }else {
+        } else {
             printf("unknown command line argument '%s', try './njvm --help'", argv[1]);
         }
     } else {
-  run:
+        run:
 //    Started
-        printf("Ninja Virtual Machine started\n");
+        if (*program.saveProgram == 1) {
-        printProgram(program);
+            printf("Ninja Virtual Machine started\n");
-        execute(program);
+            printProgram(program);
+            execute(program);
+        } else {
+            printf("Error: no program selected\n");
+            return 1;
+        }
 //    Stopped
         printf("Ninja Virtual Machine stopped\n");
         return 0;

program.c

@@ -11,6 +11,7 @@
 struct program {
     int *size;
     unsigned int *program;
+    int *saveProgram;
 };
 
 void copyToProgram(const unsigned int codeToCopy[], int size, struct program program) {
@@ -18,6 +19,7 @@ void copyToProgram(const unsigned int codeToCopy[], int size, struct program pro
         program.program[i] = codeToCopy[i];
     }
     *program.size = size;
+    *program.saveProgram = 1;
 }
 
 void printProgram(struct program program) {