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#pragma once
#ifndef __SEGA315_5881_CRYPT__
#define __SEGA315_5881_CRYPT__
typedef device_delegate<UINT16 (UINT32)> sega_m2_read_delegate;
extern const device_type SEGA315_5881_CRYPT;
#define MCFG_SET_READ_CALLBACK( _class, _method) \
sega_315_5881_crypt_device::set_read_cb(*device, sega_m2_read_delegate(&_class::_method, #_class "::" #_method, NULL, (_class *)0));
class sega_315_5881_crypt_device : public device_t
{
public:
// construction/destruction
sega_315_5881_crypt_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock);
UINT16 do_decrypt(UINT8 *&base);
void set_addr_low(UINT16 data);
void set_addr_high(UINT16 data);
void set_subkey(UINT16 data);
void set_key(UINT32 data);
sega_m2_read_delegate m_read;
static void set_read_cb(device_t &device,sega_m2_read_delegate readcb)
{
sega_315_5881_crypt_device &dev = downcast<sega_315_5881_crypt_device &>(device);
dev.m_read = readcb;
}
protected:
virtual void device_start();
virtual void device_reset();
private:
enum {
BUFFER_SIZE = 32768, LINE_SIZE = 512,
FLAG_COMPRESSED = 0x10000, FLAG_LINE_SIZE_512 = 0x20000
};
UINT32 key;
UINT8 *buffer, *line_buffer, *line_buffer_prev;
UINT32 prot_cur_address;
UINT16 subkey, dec_hist;
UINT32 dec_header;
bool enc_ready;
int buffer_pos, line_buffer_pos, line_buffer_size, buffer_bit;
struct sbox {
UINT8 table[64];
int inputs[6]; // positions of the inputs bits, -1 means no input except from key
int outputs[2]; // positions of the output bits
};
static const sbox fn1_sboxes[4][4];
static const sbox fn2_sboxes[4][4];
static const int fn1_game_key_scheduling[38][2];
static const int fn2_game_key_scheduling[34][2];
static const int fn1_sequence_key_scheduling[20][2];
static const int fn2_sequence_key_scheduling[16];
static const int fn2_middle_result_scheduling[16];
static const UINT8 trees[9][2][32];
int feistel_function(int input, const struct sbox *sboxes, UINT32 subkeys);
UINT16 block_decrypt(UINT32 game_key, UINT16 sequence_key, UINT16 counter, UINT16 data);
UINT16 get_decrypted_16();
int get_compressed_bit();
void enc_start();
void enc_fill();
void line_fill();
};
#endif
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