GBA.ino: Get rid of calcChecksumStr as a global

Frees 150 bytes of program space and 5 bytes of global ram space.

1 files changed, 23 insertions, 21 deletions

diff --git a/Cart_Reader/GBA.ino b/Cart_Reader/GBA.ino
index 2163a01..a824096 100644
--- a/Cart_Reader/GBA.ino
+++ b/Cart_Reader/GBA.ino
@@ -6,7 +6,6 @@
 /******************************************

    Variables

  *****************************************/

-char calcChecksumStr[5];

 boolean readType;

 

 /******************************************

@@ -569,6 +568,16 @@ void writeByte_GBA(unsigned long myAddress, byte myData) {
 /******************************************

   GBA ROM Functions

 *****************************************/

+// Compute the checksum of rom header

+// "header" must contain at least the rom's first 188 bytes

+byte checksumHeader_GBA(const byte *header) {

+    byte result = 0x00;

+    for (byte n = 0xA0; n < 0xBD; n++) {

+      result -= header[n];

+    }

+    return result - 0x19;

+}

+

 // Read info out of rom header

 void getCartInfo_GBA() {

   char saveTypeStr[14];

@@ -760,22 +769,21 @@ void getCartInfo_GBA() {
     // Get ROM version

     romVersion = sdBuffer[0xBC];

 

-    // Get Checksum as string

-    sprintf(checksumStr, "%02X", sdBuffer[0xBD]);

-

     // Calculate Checksum

-    int calcChecksum = 0x00;

-    for (int n = 0xA0; n < 0xBD; n++) {

-      calcChecksum -= sdBuffer[n];

-    }

-    calcChecksum = (calcChecksum - 0x19) & 0xFF;

-    // Turn into string

-    sprintf(calcChecksumStr, "%02X", calcChecksum);

+    byte calcChecksum = checksumHeader_GBA(sdBuffer);

+

+    // Convert checksum from header into string

+    // (used in compare_checksum_GBA... it should just exchange an integer

+    // instead)

+    sprintf(checksumStr, "%02X", sdBuffer[0xBD]);

 

     // Compare checksum

-    if (strcmp(calcChecksumStr, checksumStr) != 0) {

+    if (sdBuffer[0xBD] != calcChecksum) {

+      char calcChecksumStr[3];

       display_Clear();

       print_Msg(F("Result: "));

+      // Turn into string

+      sprintf(calcChecksumStr, "%02X", calcChecksum);

       println_Msg(calcChecksumStr);

       print_Error(F("Checksum Error"), false);

       println_Msg(F(""));

@@ -912,15 +920,9 @@ boolean compare_checksum_GBA() {
     myFile.read(sdBuffer, 512);

     myFile.close();

 

-    // Calculate Checksum

-    int calcChecksum = 0x00;

-    for (int n = 0xA0; n < 0xBD; n++) {

-      calcChecksum -= sdBuffer[n];

-    }

-    calcChecksum = (calcChecksum - 0x19) & 0xFF;

-

-    // Turn into string

-    sprintf(calcChecksumStr, "%02X", calcChecksum);

+    // Calculate Checksum and turn into string

+    char calcChecksumStr[3];

+    sprintf(calcChecksumStr, "%02X", checksumHeader_GBA(sdBuffer));

     print_Msg(calcChecksumStr);

 

     if (strcmp(calcChecksumStr, checksumStr) == 0) {