made new functions accessible to the calculator

src/decn/decn.c

@@ -1393,6 +1393,13 @@ void to_radian_decn(void) {
 	div_decn();
 }
 
+void pi_decn(void) {
+	set_dec80_zero(&BDecn);
+	BDecn.lsu[0] = 5; // 0.5 00 ..
+	copy_decn(&AccDecn, &DECN_2PI);
+	mult_decn();
+}
+
 
 static void set_str_error(void){
 	Buf[0] = 'E';

src/decn/decn.h

@@ -92,6 +92,7 @@ void tan_decn(void);
 void arctan_decn(void);
 void to_degree_decn(void);
 void to_radian_decn(void);
+void pi_decn(void);
 
 //Buf should hold at least 18 + 4 + 5 + 1 = 28
 #define DECN_BUF_SIZE 28