diff --git a/asm_rules.c b/asm_rules.c
index 73d4474..8050698 100644
--- a/asm_rules.c
+++ b/asm_rules.c
@@ -7,8 +7,11 @@ void trit_flip(char *in, char *instruction) {
 		in[i] = instruction[i];
 	}
 }
-int asm_rules(char *in, char _asm[27], char _asm_addr[27]){
+int asm_rules(char *in, char _asm[27]){
 	
+	for (int i = 0; i < 27; i++) {
+		_asm[i] = 0;
+	}
 	int pass = 0;
 
 	char *word = strtok(in, " ");
@@ -60,7 +63,14 @@ int asm_rules(char *in, char _asm[27], char _asm_addr[27]){
 				trit_flip(_asm, "+00000-000000");
 			} else if (strstr(word, "mov")) {
 				trit_flip(_asm, "+000000000000");
+			} else if (strstr(word, "Nst")) { //underflow test
+				trit_flip(_asm, "-------------");
+			} else if (strstr(word, "Pst")) { //overflow test
+				trit_flip(_asm, "+++++++++++++");
 			}
+
+
+
 		}
 
 		word = strtok(NULL, " ");
@@ -68,3 +78,4 @@ int asm_rules(char *in, char _asm[27], char _asm_addr[27]){
 	pass = 0;
 	return 0;
 }
+
diff --git a/main.c b/main.c
index 291b55e..b0a0f3f 100644
--- a/main.c
+++ b/main.c
@@ -1,72 +1,15 @@
 #include <stdio.h>
 #include "asm_rules.c"
 
-void bin_to_hex(char *tryte, int *hex) {
-	char *a = tryte;
-	long num = 0;
-	do {
-		long b = *a=='1'?1:0;
-		num = (num<<1)|b;
-		a++;
-	} while (*a);
-	*hex = num;
-
-}
-void asm_to_hex(char *_asm, int *opcode, int *in0, int *in1, int *out){
-
-	char tryte[108] = "\0";
-	char t0[26] = "\0"; 
-	char t1[26] = "\0"; 
-	char t2[26] = "\0"; 
-	char t3[26] = "\0"; 
-
-	int size = sizeof(_asm)/sizeof(_asm[0]);
-	//convert assembly to formated binary representation of ternary
-	for (int i = 0; i < sizeof(_asm)/4; i++) {
-		
-		//printf("%c",_asm[i]);
-		if(_asm[i]=='-') {
-			strcat(tryte, "10");
-		} else if (_asm[i]=='+') {
-			strcat(tryte, "01");
-		} else {
-			strcat(tryte, "00");
-		}
-	}
-
-	bin_to_hex(t0, opcode);
-	bin_to_hex(t1, in0);
-	bin_to_hex(t2, in1);
-	bin_to_hex(t3, out);
-}
-
+void bin_to_hex(char *tryte, int *hex);
+void asm_to_hex(char *_asm, int *opcode, int *in0, int *in1, int *out);
+int params(int argc, char **argv);
 
+FILE *dest_asm;
+FILE *src_asm;
 int main(int argc, char **argv) {
-
-	FILE *dest_asm;
-	FILE *src_asm;
-	if (argc > 2) {
-		for (int i = 1 ; i < argc; i++) {
-			if (strcmp("-i", argv[i]) == 0 || strcmp("--input", argv[i]) == 0) {
-				src_asm = fopen(argv[i+1], "r");
-				i=i+1;
-			} else if (strcmp("-o", argv[i]) == 0 || strcmp("--output", argv[i]) == 0) {
-				dest_asm = fopen(argv[i+1], "w");
-				i=i+1;
-			} else if (strcmp("-h", argv[i]) == 0 || strcmp("--help", argv[i]) == 0) {
-				printf("Usage: tasm [options] file...\n");
-				printf("Options:\n");
-				printf("-h,--help		Prints this information\n");
-				printf("-i,--input <arg> 	Path of input file\n");
-				printf("-o,--output <arg>	Path of output file\n");
-				return 0; 
-			} else {
-				printf("unknown argument: %s\n", argv[i]);
-				return 1;
-			}
-		}
-	} else {
-		printf("tasm: no input file\n");
+	int p = params(argc, argv);
+	if (p==1) {
 		return 1;
 	}
 
@@ -94,16 +37,13 @@ int main(int argc, char **argv) {
 			asm_to_hex(out_asm, &hex_op, &hex_in0, &hex_in1, &hex_out);
 
 			printf("%.5x %.5x %.5x %.5x\n", hex_op, hex_in0, hex_in1, hex_out);
-
+			// Write the hex to a file
 			fprintf(dest_asm,"%.5x ", hex_op);
 			fprintf(dest_asm,"%.5x ", hex_in0);
 			fprintf(dest_asm,"%.5x ", hex_in1);
 			fprintf(dest_asm,"%.5x \n", hex_out);
-			// Write the hex to a file
-
 			size = size + 3; //1 word = 3trytes
 		}
-
 	}
 
 	printf("\n%u trytes\n\n", size);
@@ -116,3 +56,82 @@ int main(int argc, char **argv) {
 	return 0;
 }
 
+int params(int argc, char **argv){
+	if (argc > 2) {
+		for (int i = 1 ; i < argc; i++) {
+			if (strcmp("-i", argv[i]) == 0 || strcmp("--input", argv[i]) == 0) {
+				src_asm = fopen(argv[i+1], "r");
+				i=i+1;
+			} else if (strcmp("-o", argv[i]) == 0 || strcmp("--output", argv[i]) == 0) {
+				dest_asm = fopen(argv[i+1], "w");
+				i=i+1;
+			} else if (strcmp("-h", argv[i]) == 0 || strcmp("--help", argv[i]) == 0) {
+				printf("Usage: tasm [options] file...\n");
+				printf("Options:\n");
+				printf("-h,--help		Prints this information\n");
+				printf("-i,--input <arg> 	Path of input file\n");
+				printf("-o,--output <arg>	Path of output file\n");
+				return 1; 
+			} else {
+				printf("unknown argument: %s\n", argv[i]);
+				return 1;
+			}
+		}
+	} else {
+		printf("tasm: no input file\n");
+		return 1;
+	}
+	return 0;
+}
+
+void asm_to_hex(char *_asm, int *opcode, int *in0, int *in1, int *out){
+
+	char tryte[54];
+	char t0[27]; 
+	char t1[26]; 
+	char t2[26]; 
+	char t3[26]; 
+	for (int i = 0; i < 18; i++) {
+ 		t0[i] = 0;
+ 		t1[i] = 0;
+ 		t2[i] = 0;
+ 		t3[i] = 0;
+	}
+	tryte[0] = '\0';
+
+	//convert assembly to formated binary representation of ternary
+	int i = 0;
+	do {
+		if(_asm[0]=='-') {
+			strcat(tryte, "10");
+		} else if (_asm[0]=='+') {
+			strcat(tryte, "01");
+		} else {
+			strcat(tryte, "00");
+		}
+		i++;
+	} while (i<13);
+		
+	int j = 0;
+	for (int i = 0; i < 27; i++) {
+		t0[i] = tryte[j];
+		j++;
+	}
+		j++;
+
+	bin_to_hex(t0, opcode);
+	bin_to_hex(t1, in0);
+	bin_to_hex(t2, in1);
+	bin_to_hex(t3, out);
+}
+
+void bin_to_hex(char *tryte, int *hex) {
+	for (int i = 0; i < 26; ++i){
+		if (tryte[i] == '1' ){
+			*hex = (*hex << 1)|1;
+		} else {
+			*hex = (*hex << 1)|0;
+		}
+	}
+}
+