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// license:BSD-3-Clause
// copyright-holders:Nicola Salmoria, Andreas Naive, Charles MacDonald
/***************************************************************************
Hitachi FD1089A/FD1089B encryption emulation
****************************************************************************
Copyright Nicola Salmoria, Andreas Naive, and Charles MacDonald.
All rights reserved.
***************************************************************************/
#ifndef __FD1089_H__
#define __FD1089_H__
#include "cpu/m68000/m68000.h"
//**************************************************************************
// CONSTANTS
//**************************************************************************
// device type definition
extern const device_type FD1089A;
extern const device_type FD1089B;
//**************************************************************************
// TYPE DEFINITIONS
//**************************************************************************
// ======================> fd1089_base_device
// base device, shared implementation between A and B variants
class fd1089_base_device : public m68000_device
{
public:
// construction/destruction
fd1089_base_device(const machine_config &mconfig, device_type type, const char *name, const char *tag, device_t *owner, UINT32 clock, const char *shortname, const char *source);
// explicit decryption helpers
void decrypt(offs_t baseaddr, UINT32 size, offs_t regionoffs, UINT16 *opcodesptr, UINT16 *dataptr) { decrypt(baseaddr, size, &m_plaintext[regionoffs/2], opcodesptr, dataptr); }
protected:
// device overrides
virtual void device_start() override;
// internal helpers
UINT8 rearrange_key(UINT8 table, bool opcode);
virtual UINT8 decode(UINT8 val, UINT8 key, bool opcode) = 0;
UINT16 decrypt_one(offs_t addr, UINT16 val, const UINT8 *key, bool opcode);
void decrypt(offs_t baseaddr, UINT32 size, const UINT16 *srcptr, UINT16 *opcodesptr, UINT16 *dataptr);
// internal state
required_memory_region m_region;
required_region_ptr<UINT8> m_key;
std::vector<UINT16> m_plaintext;
required_shared_ptr<UINT16> m_decrypted_opcodes;
// internal types
struct decrypt_parameters
{
UINT8 xorval;
UINT8 s7,s6,s5,s4,s3,s2,s1,s0;
};
// static tables
static const UINT8 s_basetable_fd1089[0x100];
static const decrypt_parameters s_addr_params[16];
static const decrypt_parameters s_data_params_a[16];
};
// ======================> fd1089a_device
// FD1089A variant
class fd1089a_device : public fd1089_base_device
{
public:
// construction/destruction
fd1089a_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock);
protected:
virtual UINT8 decode(UINT8 val, UINT8 key, bool opcode) override;
};
// ======================> fd1089b_device
// FD1089B variant
class fd1089b_device : public fd1089_base_device
{
public:
// construction/destruction
fd1089b_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock);
protected:
virtual UINT8 decode(UINT8 val, UINT8 key, bool opcode) override;
};
#endif
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