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Improve DSiWare save creation (#1375)

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Pk11 2022-03-07 14:08:29 -06:00 committed by GitHub
parent c66df57256
commit c3adf6f606
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1 changed files with 39 additions and 22 deletions
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61
src/DSi_NAND.cpp
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@ -919,29 +919,44 @@ bool CreateSaveFile(const char* path, u32 len)
u32 clustersize, maxfiles, totsec16, fatsz16;
// CHECKME!
// code inspired from https://github.com/JeffRuLz/TMFH/blob/master/arm9/src/sav.c
if (len < 573440)
// code inspired from https://github.com/Epicpkmn11/NTM/blob/master/arm9/src/sav.c
const u16 sectorsize = 0x200;
// fit maximum sectors for the size
const u16 maxsectors = len / sectorsize;
u16 tracksize = 1;
u16 headcount = 1;
u16 totsec16next = 0;
while (totsec16next <= maxsectors)
{
clustersize = 512;
maxfiles = 16;
totsec16next = tracksize * (headcount + 1) * (headcount + 1);
if (totsec16next <= maxsectors)
{
headcount++;
totsec16 = totsec16next;
tracksize++;
totsec16next = tracksize * headcount * headcount;
if (totsec16next <= maxsectors)
{
totsec16 = totsec16next;
}
}
}
else if (len < 5472256)
totsec16next = (tracksize + 1) * headcount * headcount;
if (totsec16next <= maxsectors)
{
clustersize = 2048;
maxfiles = 256;
}
else
{
clustersize = 4096;
maxfiles = 256;
tracksize++;
totsec16 = totsec16next;
}
if (len <= 0x4000) fatsz16 = 1;
else if (len <= 0x200000) fatsz16 = 3;
else fatsz16 = 6;
maxfiles = len < 0x8C000 ? 0x20 : 0x200;
clustersize = (totsec16 > (8 << 10)) ? 8 : (totsec16 > (1 << 10) ? 4 : 1);
if (len == 0x4000) totsec16 = 27;
else totsec16 = len >> 9;
#define ALIGN(v, a) (((v) % (a)) ? ((v) + (a) - ((v) % (a))) : (v))
u16 totalclusters = ALIGN(totsec16, clustersize) / clustersize;
u32 fatbytes = (ALIGN(totalclusters, 2) / 2) * 3; // 2 sectors -> 3 byte
fatsz16 = ALIGN(fatbytes, sectorsize) / sectorsize;
FF_FIL file;
FRESULT res;
@ -960,17 +975,19 @@ bool CreateSaveFile(const char* path, u32 len)
// create FAT header
data[0x000] = 0xE9;
memcpy(&data[0x003], "MSWIN4.1", 8);
*(u16*)&data[0x00B] = 512; // bytes per sector
data[0x00D] = clustersize >> 9;
*(u16*)&data[0x00B] = sectorsize; // bytes per sector
data[0x00D] = clustersize;
*(u16*)&data[0x00E] = 1; // reserved sectors
data[0x010] = 2; // num FATs
*(u16*)&data[0x011] = maxfiles << 1;
*(u16*)&data[0x011] = maxfiles;
*(u16*)&data[0x013] = totsec16;
data[0x015] = 0xF8;
*(u16*)&data[0x016] = fatsz16;
data[0x024] = 0x07;
*(u16*)&data[0x018] = tracksize;
*(u16*)&data[0x01A] = headcount;
data[0x024] = 0x05;
data[0x026] = 0x29;
*(u32*)&data[0x027] = 305419896;
*(u32*)&data[0x027] = 0x12345678;
memcpy(&data[0x02B], "VOLUMELABEL", 11);
memcpy(&data[0x036], "FAT12 ", 8);
*(u16*)&data[0x1FE] = 0xAA55;