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// license:BSD-3-Clause
// copyright-holders:Morten Shearman Kirkegaard, Samuel Neves, Peter Wilhelmsen
/*************************************************************************
atarixga.h
Atari XGA encryption FPGAs
*************************************************************************/
#ifndef MAME_MACHINE_ATARIXGA_H
#define MAME_MACHINE_ATARIXGA_H
DECLARE_DEVICE_TYPE(ATARI_136094_0072, atari_136094_0072_device)
DECLARE_DEVICE_TYPE(ATARI_136095_0072, atari_136095_0072_device)
class atari_xga_device : public device_t
{
public:
virtual void write(offs_t offset, uint32_t data, uint32_t mem_mask = ~0) = 0;
virtual uint32_t read(offs_t offset, uint32_t mem_mask = ~0) = 0;
protected:
// construction/destruction
atari_xga_device(const machine_config &mconfig, device_type type, const char *tag, device_t *owner, uint32_t clock)
: device_t(mconfig, type, tag, owner, clock)
{
}
virtual void device_start() override = 0;
virtual void device_reset() override = 0;
std::unique_ptr<uint16_t[]> m_ram; // CY7C185-45PC, only 16-Kbit used
};
class atari_136094_0072_device : public atari_xga_device
{
public:
atari_136094_0072_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock);
virtual void write(offs_t offset, uint32_t data, uint32_t mem_mask = ~0) override;
virtual uint32_t read(offs_t offset, uint32_t mem_mask = ~0) override;
protected:
virtual void device_start() override;
virtual void device_reset() override;
private:
static const size_t RAM_WORDS = 2048;
uint16_t powers2(uint8_t k, uint16_t x);
uint16_t lfsr2(uint16_t x);
uint16_t lfsr1(uint16_t x);
uint16_t decipher(uint8_t k, uint16_t c);
enum fpga_mode
{
FPGA_RESET,
FPGA_SETKEY,
FPGA_DECIPHER
};
fpga_mode m_mode{};
uint16_t m_address = 0; // last written address
uint16_t m_ciphertext = 0; // last written ciphertext
};
class atari_136095_0072_device : public atari_xga_device
{
public:
atari_136095_0072_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock);
void polylsb_write(offs_t offset, uint32_t data);
uint32_t polylsb_read(offs_t offset, uint32_t mem_mask = ~0);
virtual void write(offs_t offset, uint32_t data, uint32_t mem_mask = ~0) override;
virtual uint32_t read(offs_t offset, uint32_t mem_mask = ~0) override;
protected:
virtual void device_start() override;
virtual void device_reset() override;
private:
static const size_t RAM_WORDS = 4096;
uint16_t powers2(uint8_t k, uint16_t x);
uint16_t lfsr2(uint16_t x);
uint16_t lfsr1(uint16_t x);
uint16_t decipher(uint8_t k, uint16_t c);
enum fpga_mode
{
FPGA_SETKEY,
FPGA_DECIPHER,
FPGA_PROCESS,
FPGA_RESULT
};
struct
{
uint16_t addr = 0;
uint32_t data[64]{};
} m_update;
fpga_mode m_mode{};
uint8_t m_poly_lsb = 0;
uint16_t m_reply = 0;
};
#endif // MAME_MACHINE_ATARIXGA_H
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