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Use header values for rom and sram start/end instead of hardcoding

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This commit is contained in:
Roger Braunstein 2023-07-06 14:11:54 -07:00
parent 4621ad20f3
commit 1dccf84d9f
1 changed files with 19 additions and 9 deletions
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28
Cart_Reader/LOOPY.ino
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@ -3,6 +3,9 @@
//******************************************
// IMPORTANT: All data are stored as BIG-ENDIAN. Many ROM dumps online are little endian.
// See https://github.com/kasamikona/Loopy-Tools/blob/master/ROM%20Structure.md
//
// By @partlyhuman
// Special thanks to @kasamikona
#ifdef enable_LOOPY
// SH-1 memory map locations, ROM starts here
@ -19,6 +22,8 @@ const int LOOPY_RAMCS2 = A7;
// The internal checksum read from the cart header at 08h, will be checked against an actual sum
uint32_t loopyChecksum;
uint32_t loopyChecksumStart;
uint32_t loopyChecksumEnd;
// Whether the cart was found (by checksum) in the database
bool loopyCartRecognized;
@ -403,9 +408,18 @@ void getCartInfo_LOOPY() {
// Set control
dataIn_LOOPY();
// Last word of ROM stored as 32-bit pointer at 000004h
uint32_t headerRomSize = ((uint32_t)readWord_LOOPY(0x4) << 16) | (uint32_t)readWord_LOOPY(0x6);
cartSize = headerRomSize - LOOPY_MAP_ROM_ZERO + 2;
// First word after header stored as 32-bit pointer at 0h, final word (inclusive) at 4h
// based on SH-1 memory mapped location of ROM (shift to rebase on zero)
loopyChecksumStart = (((uint32_t)readWord_LOOPY(0x0) << 16) | (uint32_t)readWord_LOOPY(0x2)) - LOOPY_MAP_ROM_ZERO;
loopyChecksumEnd = (((uint32_t)readWord_LOOPY(0x4) << 16) | (uint32_t)readWord_LOOPY(0x6)) - LOOPY_MAP_ROM_ZERO;
// Full cart size DOES include the header, don't subtract it off :)
cartSize = loopyChecksumEnd + 2;
// SRAM first and last byte locations stored at 10h and 14h, based on SH-1 memory mapped location of SRAM
uint32_t loopySramStart = (((uint32_t)readWord_LOOPY(0x10) << 16) | (uint32_t)readWord_LOOPY(0x12)) - LOOPY_MAP_SRAM_ZERO;
uint32_t loopySramEnd = (((uint32_t)readWord_LOOPY(0x14) << 16) | (uint32_t)readWord_LOOPY(0x16)) - LOOPY_MAP_SRAM_ZERO;
sramSize = loopySramEnd - loopySramStart + 1;
// TODO sanity check these values
// Get internal checksum from header
loopyChecksum = ((uint32_t)readWord_LOOPY(0x8) << 16) | (uint32_t)readWord_LOOPY(0xA);
@ -423,10 +437,6 @@ void getCartInfo_LOOPY() {
print_Msg(F("Size: "));
print_Msg(cartSize * 8 / 1024 / 1024);
println_Msg(F(" MBit"));
// SRAM size can be calculated from subtracting 32bit pointers 000014h (last byte of sram, memory mapped) - 000010h (first byte of sram, memory mapped)
// But this is fine
sramSize = LOOPY_SRAM_SIZE;
print_Msg(F("Sram: "));
print_Msg(sramSize * 8 / 1024);
println_Msg(F(" KBit"));
@ -477,8 +487,8 @@ void readROM_LOOPY() {
word myWord = readWord_LOOPY(ptr);
// aggregate checksum over 16-bit words, starting at 80h, this address is stored in header but never varies
if (ptr >= 0x80) {
sum += myWord;
if (ptr >= loopyChecksumStart) {
sum += myWord;
}
// Store in buffer