a lot of work

- round to nearest instead of round to zero in SMS period calc
- implement arpeggio
- implement arp macro (kinda)
- polish the SMS platform
- correct the DIV_CMD_PITCH range to 1 semitone
- fix PSG volume in Genesis
- use a better register write strat in Genesis
- fix a bug caused by legacy code
- implement ECxx command
- implement EDxx command
- implement SN noise mode command
- vibrato table is now 64 positions long (instead of 60)

src/main.cpp

@@ -27,6 +27,11 @@ int main(int argc, char** argv) {
     return 1;
   }
   ssize_t len=ftell(f);
+  if (len==0x7fffffffffffffff) {
+    perror("could not get file length");
+    fclose(f);
+    return 1;
+  }
   if (len<1) {
     if (len==0) {
       printf("that file is empty!\n");