Add fallback if ROM size in MD header is 0

1 files changed, 11 insertions, 9 deletions

diff --git a/Cart_Reader/MD.ino b/Cart_Reader/MD.ino
index 69b74d1..659555a 100644
--- a/Cart_Reader/MD.ino
+++ b/Cart_Reader/MD.ino
@@ -1091,6 +1091,17 @@ void getCartInfo_MD() {
     cartSize = 0x80000;

   }

 

+  // Some games are missing the ROM size in the header, in this case calculate ROM size by looking for mirror of the first line of the ROM

+  // This does not work for cartridges that have SRAM mapped directly after the maskrom like Striker (Europe)

+  if ((cartSize < 0x8000) || (cartSize > 0xEAF400)) {

+    for (cartSize = 0x20000 / 2; cartSize < 0x400000 / 2; cartSize += 0x20000 / 2) {

+      if ((readWord_MD(0x0) == readWord_MD(cartSize)) && (readWord_MD(0x1) == readWord_MD(0x1 + cartSize)) && (readWord_MD(0x2) == readWord_MD(0x2 + cartSize)) && (readWord_MD(0x3) == readWord_MD(0x3 + cartSize)) && (readWord_MD(0x4) == readWord_MD(0x4 + cartSize)) && (readWord_MD(0x5) == readWord_MD(0x5 + cartSize)) && (readWord_MD(0x6) == readWord_MD(0x6 + cartSize)) && (readWord_MD(0x7) == readWord_MD(0x7 + cartSize)) && (readWord_MD(0x8) == readWord_MD(0x8 + cartSize))) {

+        break;

+      }

+    }

+    cartSize = cartSize * 2;

+  }

+

   display_Clear();

   println_Msg(F("Cart Info"));

   println_Msg(F(" "));

@@ -1249,9 +1260,6 @@ void readROM_MD() {
 

   byte buffer[1024] = { 0 };

 

-  // get current time

-  // unsigned long startTime = millis();

-

   // Phantasy Star/Beyond Oasis with 74HC74 and 74HC139 switch ROM/SRAM at address 0x200000

   if (0x200000 < cartSize && cartSize < 0x400000) {

     enableSram_MD(0);

@@ -1475,12 +1483,6 @@ void readROM_MD() {
     writeSSF2Map(0x50987F, 7);  // 0xA130FF

   }

 

-  // print elapsed time

-  //print_Msg(F("Time elapsed: "));

-  //print_Msg((millis() - startTime) / 1000);

-  //println_Msg(F("s"));

-  //display_Update();

-

   // Calculate internal checksum

   print_Msg(F("Internal checksum..."));

   display_Update();