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naomi: faster gdrom loading

This commit is contained in:
Flyinghead 2019-12-15 21:22:51 +01:00
parent 29fd406dd8
commit 7ab275d4b5
2 changed files with 13 additions and 30 deletions
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36
core/hw/naomi/gdcartridge.cpp
View File

@ -221,8 +221,7 @@ const u8 GDCartridge::DES_ROTATE_TABLE[16] = {
void GDCartridge::permutate(u32 &a, u32 &b, u32 m, int shift)
{
u32 temp;
temp = ((a>>shift) ^ b) & m;
u32 temp = ((a>>shift) ^ b) & m;
a ^= temp<<shift;
b ^= temp;
}
@ -311,7 +310,8 @@ void GDCartridge::des_generate_subkeys(const u64 key, u32 *subkeys)
}
}
u64 GDCartridge::des_encrypt_decrypt(bool decrypt, u64 src, const u32 *des_subkeys)
template<bool decrypt>
u64 GDCartridge::des_encrypt_decrypt(u64 src, const u32 *des_subkeys)
{
u32 r = (src & 0x00000000ffffffffULL) >> 0;
u32 l = (src & 0xffffffff00000000ULL) >> 32;
@ -389,22 +389,6 @@ u64 GDCartridge::rev64(u64 src)
return ret;
}
u64 GDCartridge::read_to_qword(const u8 *region)
{
u64 ret = 0;
for(int i=0;i<8;i++)
ret |= u64(region[i]) << (56-(8*i));
return ret;
}
void GDCartridge::write_from_qword(u8 *region, u64 qword)
{
for(int i=0;i<8;i++)
region[i] = qword >> (56-(i*8));
}
void GDCartridge::find_file(const char *name, const u8 *dir_sector, u32 &file_start, u32 &file_size)
{
file_start = 0;
@ -449,9 +433,9 @@ void GDCartridge::find_file(const char *name, const u8 *dir_sector, u32 &file_st
}
}
void GDCartridge::read_gdrom(Disc *gdrom, u32 sector, u8* dst)
void GDCartridge::read_gdrom(Disc *gdrom, u32 sector, u8* dst, u32 count)
{
gdrom->ReadSectors(sector + 150, 1, dst, 2048);
gdrom->ReadSectors(sector + 150, count, dst, 2048);
}
void GDCartridge::device_start()
@ -567,7 +551,8 @@ void GDCartridge::device_start()
if (file_start) {
u32 file_rounded_size = (file_size + 2047) & -2048;
for (dimm_data_size = 4096; dimm_data_size < file_rounded_size; dimm_data_size <<= 1);
for (dimm_data_size = 4096; dimm_data_size < file_rounded_size; dimm_data_size <<= 1)
;
dimm_data = (u8 *)malloc(dimm_data_size);
verify(dimm_data != NULL);
if (dimm_data_size != file_rounded_size)
@ -575,17 +560,16 @@ void GDCartridge::device_start()
// read encrypted data into dimm_data
u32 sectors = file_rounded_size / 2048;
for (u32 sec = 0; sec != sectors; sec++)
read_gdrom(gdrom, file_start + sec, dimm_data + 2048 * sec);
read_gdrom(gdrom, file_start, dimm_data, sectors);
// decrypt loaded data
u32 des_subkeys[32];
des_generate_subkeys(rev64(key), des_subkeys);
for (int i = 0; i < file_rounded_size; i += 8)
write_from_qword(dimm_data + i, rev64(des_encrypt_decrypt(true, rev64(read_to_qword(dimm_data + i)), des_subkeys)));
*(u64 *)(dimm_data + i) = des_encrypt_decrypt<true>(*(u64 *)(dimm_data + i), des_subkeys);
}
// decrypt loaded data
delete gdrom;
if (!dimm_data)

7
core/hw/naomi/gdcartridge.h
View File

@ -70,11 +70,10 @@ private:
inline void permutate(u32 &a, u32 &b, u32 m, int shift);
void des_generate_subkeys(const u64 key, u32 *subkeys);
u64 des_encrypt_decrypt(bool decrypt, u64 src, const u32 *des_subkeys);
template<bool decrypt>
u64 des_encrypt_decrypt(u64 src, const u32 *des_subkeys);
u64 rev64(u64 src);
u64 read_to_qword(const u8 *region);
void write_from_qword(u8 *region, u64 qword);
void read_gdrom(Disc *gdrom, u32 sector, u8* dst);
void read_gdrom(Disc *gdrom, u32 sector, u8* dst, u32 count = 1);
};
#endif /* CORE_HW_NAOMI_GDCARTRIDGE_H_ */