diff --git a/cpu.c b/cpu.c
index f8e03d9..f84901e 100644
--- a/cpu.c
+++ b/cpu.c
@@ -4,6 +4,10 @@
 #include <math.h>
 #include <string.h>
 
+/* Known errors:
+ * 1) Exec does the calculations on the first clock cycle, there is a bug where in some cases exec isn't run on the last cycle and because of this the CPU still works.
+ */
+
 
 struct fetch_data_t *malloc_fetch_data(){
 	struct fetch_data_t *ret=malloc(sizeof(struct fetch_data_t));
@@ -606,44 +610,54 @@ int cpu_cycle_clock(struct simdata_t *simdata){
 	free_instr_list(&simdata->cpu_gui_hints->fetching_list);
 	free_instr_list(&simdata->cpu_gui_hints->decoding_list);
 	free_instr_list(&simdata->cpu_gui_hints->executing_list);
-	switch(exec(simdata)){
-		case 0:  break;
-		case 2:  return 4;
-		default: return 1;
+	switch(simdata->cpu_structure){
+		case CPU_STRUCTURE_SIMPLE_PIPELINED:
+			switch(exec(simdata)){
+				case 0:  break;
+				case 2:  return 4;
+				default: return 1;
+			}
+			switch(decode(simdata)){
+				case 0:  break;
+				default: return 2;
+			}
+			switch(fetch(simdata)){
+				case 0:  break;
+				default: return 3;
+			}
+			break;
+		case CPU_STRUCTURE_SIMPLE_NON_PIPELINED:
+			switch(state){
+				case 0:
+					switch(fetch(simdata)){
+						case 0:  break;
+						default: return 3;
+					}
+					break;
+				case 1:
+					switch(decode(simdata)){
+						case 0:  break;
+						default: return 2;
+					}
+					break;
+				case 2:
+					switch(exec(simdata)){
+						case 0:  break;
+						case 2:  return 4;
+						default: return 1;
+					}
+					break;
+			}
+			if(state==2){
+				if(simdata->decode_data->exec_done)
+					state=0;
+			}else
+				state++;
+			break;
+		default:
+			return 4;
+
 	}
-	switch(decode(simdata)){
-		case 0:  break;
-		default: return 2;
-	}
-	switch(fetch(simdata)){
-		case 0:  break;
-		default: return 3;
-	}
-//	switch(state){
-//		case 0:
-//			switch(fetch(simdata)){
-//				case 0:  break;
-//				default: return 3;
-//			}
-//			break;
-//		case 1:
-//			switch(decode(simdata)){
-//				case 0:  break;
-//				default: return 2;
-//			}
-//			break;
-//		case 2:
-//			switch(exec(simdata)){
-//				case 0:  break;
-//				case 2:  return 4;
-//				default: return 1;
-//			}
-//			break;
-//	}
-//	if(state==2)
-//		state=0;
-//	else
-//		state++;
 	simdata->current_clock++;
 	return 0;
 }
diff --git a/main.c b/main.c
index bbb0ae2..689560b 100644
--- a/main.c
+++ b/main.c
@@ -42,6 +42,8 @@ void help(char* progname){
 			"                            braille\n"
 #endif
 			"  -o < file >               Output simualtion data to specified json log file\n"
+			"  -S < cpu structure >      Select the structure of the cpu. You can choose one\n"
+			"                            of the following: simple, pipelined\n"
 			, progname);
 }
 
@@ -62,9 +64,13 @@ int main(int argc, char* argd[] ){
 	char *assemble = NULL;
 	enum FB_DRIVER_t fb_driver=FB_BRAILLE;
 	int opt;
+
 	char *json_log_filename=NULL;
 	FILE *JSON_LOG_FILE;
-	while ((opt = getopt(argc, argd, "hi:a:r:o:")) != -1) {
+
+	char *structure="pipelined";
+
+	while ((opt = getopt(argc, argd, "hi:a:r:o:S:")) != -1) {
 		switch (opt) {
 			case 'h':
 				help(argd[0]);
@@ -94,6 +100,9 @@ int main(int argc, char* argd[] ){
 			case 'o':
 				json_log_filename=optarg;
 				break;
+			case 'S':
+				structure=optarg;
+				break;
 			default:
 				help(argd[0]);
 				return 1;
@@ -110,6 +119,7 @@ int main(int argc, char* argd[] ){
 		help(argd[0]);
 		return 1;
 	}
+
 	if (json_log_filename){
 		JSON_LOG_FILE=fopen(json_log_filename,"w");
 		if(JSON_LOG_FILE==NULL){
@@ -133,6 +143,19 @@ int main(int argc, char* argd[] ){
 		return 1;
 	}
 
+	if(strcmp("simple",structure)==0){
+		simdata->cpu_structure=CPU_STRUCTURE_SIMPLE_NON_PIPELINED;
+	}else if(strcmp("pipelined",structure)==0){
+		simdata->cpu_structure=CPU_STRUCTURE_SIMPLE_PIPELINED;
+	}else{
+		printf("Invalid cpu structure \"%s\"\n",structure);
+		fclose(rom);
+		free_simdata(simdata);
+		return 1;
+	}
+
+
+
 	if ( assemble != NULL ){
 		/* RUN ASSEMBLER */
 		struct assembler_context_t *assembler_context=malloc_assembler_context();
diff --git a/simdata.c b/simdata.c
index b964e81..b34a011 100644
--- a/simdata.c
+++ b/simdata.c
@@ -46,7 +46,6 @@ struct simdata_t *init_simdata(){
 	ret->cpu_gui_hints->executing_list=NULL;
 	ret->terminal_output=malloc(0);
 	ret->terminal_output_size=0;
-	ret->cpu_structure=CPU_STRUCTURE_SIMPLE_PIPELINED;
 	return ret;
 }