Fix issue where void pointers were being dereferenced

In calls to move_stack_pointer(), intial_stack_pointer should not be dereferenced in the call
This was causing page faults but this has now been corrected

userprog/populate_stack.c

@@ -29,27 +29,27 @@ void populate_stack(void** stack_pointer, int argc, char** argv) {
 		memcpy(*stack_pointer, argv[i], strlen(argv[i]) + 1);
 	}
 
-    move_stack_pointer(*stack_pointer, -4); //Moves the stack pointer back 4
+    move_stack_pointer(stack_pointer, -4); //Moves the stack pointer back 4
 
 	(*(int *)(*stack_pointer)) = 0;//sentinel          
 	i = argc;
 
 	while (--i >= 0)
 	{
-		move_stack_pointer(*stack_pointer, -4); //32bit  Moves the stack pointer back 4
+		move_stack_pointer(stack_pointer, -4); //32bit  Moves the stack pointer back 4
 
 		(*(uint32_t **)(*stack_pointer)) = arr[i];
 	}
 	
-	move_stack_pointer(*stack_pointer, -4);
-    move_stack_pointer(*stack_pointer, 4); //Moves the stack pointer forwards 4
+	move_stack_pointer(stack_pointer, -4);
+    move_stack_pointer(stack_pointer, 4); //Moves the stack pointer forwards 4
     // TODO: Test if still required in later version
     
 	(*(uintptr_t  **)(*stack_pointer)) = *stack_pointer;
-	move_stack_pointer(*stack_pointer, -4); //Moves the stack pointer back 4
+	move_stack_pointer(stack_pointer, -4); //Moves the stack pointer back 4
 
 	*(int *)(*stack_pointer) = argc;
-	move_stack_pointer(*stack_pointer, -4); //Moves the stack pointer back 4
+	move_stack_pointer(stack_pointer, -4); //Moves the stack pointer back 4
 
 	(*(int *)(*stack_pointer)) = 0;
 }
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