Mirrors/cartreader
2
0
Fork 0
mirror of https://github.com/sanni/cartreader.git synced 2024-11-11 07:25:07 +01:00
Code Issues Projects Releases Wiki Activity

NES.ino: Simplify CRC functions.

Browse Source 
It seems crc32EEP only exists because the actual number of bytes read from
file were not checked, hence falling back to smaller reads.
Instead, always read up to the full available buffer, adding to the CRC
only as many bytes as were actually read.
Also, move some related variables to local scope.
Overall, this saves about 50 bytes of code and 80 bytes of global ram.
This commit is contained in:
Vincent Pelletier 2022-10-22 03:00:59 +00:00
parent b84f63d1dc
commit d81f2c0509
1 changed files with 18 additions and 42 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

60
Cart_Reader/NES.ino
View File

@ -1458,45 +1458,21 @@ int int_pow(int base, int exp) { // Power for int
/****************************************** /******************************************
CRC Functions CRC Functions
*****************************************/ *****************************************/
FsFile crcFile;
char tempCRC[9];
uint32_t crc32(FsFile& file, uint32_t& charcnt) { void calcCRC(char* checkFile, uint32_t* crcCopy, unsigned long offset) {
uint32_t oldcrc32 = 0xFFFFFFFF; uint32_t crc = 0xFFFFFFFF;
charcnt = 0; char tempCRC[9];
while (file.available()) { int byte_count;
crcFile.read(sdBuffer, 512); FsFile crcFile = sd.open(checkFile);
for (int x = 0; x < 512; x++) {
uint8_t c = sdBuffer[x];
charcnt++;
oldcrc32 = updateCRC(c, oldcrc32);
}
}
return ~oldcrc32;
}
uint32_t crc32EEP(FsFile& file, uint32_t& charcnt) {
uint32_t oldcrc32 = 0xFFFFFFFF;
charcnt = 0;
while (file.available()) {
crcFile.read(sdBuffer, 128);
for (int x = 0; x < 128; x++) {
uint8_t c = sdBuffer[x];
charcnt++;
oldcrc32 = updateCRC(c, oldcrc32);
}
}
return ~oldcrc32;
}
void calcCRC(char* checkFile, unsigned long filesize, uint32_t* crcCopy, unsigned long offset) {
uint32_t crc;
crcFile = sd.open(checkFile);
crcFile.seek(offset); crcFile.seek(offset);
if (filesize < 1024) while (crcFile.available()) {
crc = crc32EEP(crcFile, filesize); byte_count = crcFile.read(sdBuffer, sizeof(sdBuffer));
else for (int x = 0; x < byte_count; x++) {
crc = crc32(crcFile, filesize); uint8_t c = sdBuffer[x];
crc = updateCRC(c, crc);
}
}
crc = ~crc;
crcFile.close(); crcFile.close();
sprintf(tempCRC, "%08lX", crc); sprintf(tempCRC, "%08lX", crc);
@ -1753,7 +1729,7 @@ void outputNES() {
println_Msg(F("")); println_Msg(F(""));
display_Update(); display_Update();
calcCRC(outputFile, (prg + chr) * 1024, NULL, crcOffset); calcCRC(outputFile, NULL, crcOffset);
LED_RED_OFF; LED_RED_OFF;
LED_GREEN_OFF; LED_GREEN_OFF;
LED_BLUE_OFF; LED_BLUE_OFF;
@ -3671,7 +3647,7 @@ void readPRG(boolean readrom) {
println_Msg(F("")); println_Msg(F(""));
display_Update(); display_Update();
#ifndef nointro #ifndef nointro
calcCRC(fileName, prg * 1024, &prg_crc32, 0); calcCRC(fileName, &prg_crc32, 0);
#endif #endif
} }
} }
@ -4396,7 +4372,7 @@ void readCHR(boolean readrom) {
println_Msg(F("")); println_Msg(F(""));
display_Update(); display_Update();
#ifndef nointro #ifndef nointro
calcCRC(fileName, chr * 1024, &chr_crc32, 0); calcCRC(fileName, &chr_crc32, 0);
#endif #endif
} }
} }
@ -4585,9 +4561,9 @@ void readRAM() {
display_Update(); display_Update();
if ((mapper == 16) || (mapper == 159)) if ((mapper == 16) || (mapper == 159))
calcCRC(fileName, eepsize, NULL, 0); calcCRC(fileName, NULL, 0);
else else
calcCRC(fileName, ram * 1024, NULL, 0); calcCRC(fileName, NULL, 0);
} }
} }
set_address(0); set_address(0);