/*************************************************************************** 6883sam.h Motorola 6883 Synchronous Address Multiplexer ***************************************************************************/ #pragma once #ifndef __6883SAM__ #define __6883SAM__ #include "emu.h" #define MCFG_SAM6883_ADD(_tag, _clock, _config) \ MCFG_DEVICE_ADD(_tag, SAM6883, _clock) \ MCFG_DEVICE_CONFIG(_config) #define MCFG_SAM6883_RES_CALLBACK(_read) \ devcb = &sam6883_device::set_res_rd_callback(*device, DEVCB2_##_read); /* interface */ struct sam6883_interface { /* the CPU/space from which the SAM reads data */ const char * m_cpu_tag; address_spacenum m_cpu_space; }; //************************************************************************** // SAM6883 CORE //************************************************************************** // base class so that GIME emulation can use some functionality class sam6883_friend_device { public: sam6883_friend_device() { m_cpu = NULL; m_sam_state = 0x0000; } protected: // SAM state constants static const UINT16 SAM_STATE_TY = 0x8000; static const UINT16 SAM_STATE_M1 = 0x4000; static const UINT16 SAM_STATE_M0 = 0x2000; static const UINT16 SAM_STATE_R1 = 0x1000; static const UINT16 SAM_STATE_R0 = 0x0800; static const UINT16 SAM_STATE_P1 = 0x0400; static const UINT16 SAM_STATE_F6 = 0x0200; static const UINT16 SAM_STATE_F5 = 0x0100; static const UINT16 SAM_STATE_F4 = 0x0080; static const UINT16 SAM_STATE_F3 = 0x0040; static const UINT16 SAM_STATE_F2 = 0x0020; static const UINT16 SAM_STATE_F1 = 0x0010; static const UINT16 SAM_STATE_F0 = 0x0008; static const UINT16 SAM_STATE_V2 = 0x0004; static const UINT16 SAM_STATE_V1 = 0x0002; static const UINT16 SAM_STATE_V0 = 0x0001; // incidentals cpu_device * m_cpu; // device state UINT16 m_sam_state; ATTR_FORCE_INLINE UINT16 display_offset(void) { return ((m_sam_state & (SAM_STATE_F0|SAM_STATE_F1|SAM_STATE_F2|SAM_STATE_F3|SAM_STATE_F4|SAM_STATE_F5|SAM_STATE_F6)) / SAM_STATE_F0) << 9; } ATTR_FORCE_INLINE UINT16 alter_sam_state(offs_t offset) { /* determine the mask */ UINT16 mask = 1 << (offset >> 1); /* determine the new state */ UINT16 new_state; if (offset & 0x0001) new_state = m_sam_state | mask; else new_state = m_sam_state & ~mask; /* specify the new state */ UINT16 xorval = m_sam_state ^ new_state; m_sam_state = new_state; return xorval; } void update_cpu_clock(void); }; class sam6883_device : public device_t, public sam6883_friend_device { public: sam6883_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock); template static devcb2_base &set_res_rd_callback(device_t &device, _Object object) { return downcast(device).m_read_res.set_callback(object); } // called to configure banks void configure_bank(int bank, UINT8 *memory, UINT32 memory_size, bool is_read_only); void configure_bank(int bank, read8_delegate rhandler, write8_delegate whandler); // typically called by VDG ATTR_FORCE_INLINE DECLARE_READ8_MEMBER( display_read ) { if (offset == (offs_t) ~0) { /* the VDG is telling the counter to reset */ m_counter = display_offset(); m_counter_xdiv = 0; m_counter_ydiv = 0; } else if ((offset & 1) != (m_counter & 0x0001)) { /* DA0 has been toggled - first bump B0-B3 of the counter */ bool bit3_carry = (m_counter & 0x000F) == 0x000F; m_counter = (m_counter & ~0x000F) | ((m_counter + 1) & 0x000F); /* and apply the carry (if applicable */ if (bit3_carry) counter_carry_bit3(); } return m_read_res((m_counter & m_counter_mask) | m_counter_or); } DECLARE_WRITE_LINE_MEMBER( hs_w ); // typically called by machine address_space *mpu_address_space(void) const { return m_cpu_space; } void set_bank_offset(int bank, offs_t offset); protected: // device-level overrides virtual void device_start(); virtual void device_reset(); virtual void device_post_load(); private: // represents an external memory bank - memory or IO that the SAM // points to with the S2/S1/S0 output struct sam_bank { UINT8 * m_memory; UINT32 m_memory_size; offs_t m_memory_offset; bool m_memory_read_only; read8_delegate m_rhandler; write8_delegate m_whandler; }; // represents one of the memory "spaces" (e.g. - $8000-$9FFF) that // can ultimately point to a bank template class sam_space { public: sam_space(sam6883_device &owner); void point(const sam_bank *bank, UINT16 offset, UINT16 mask); private: sam6883_device & m_owner; memory_bank * m_read_bank; memory_bank * m_write_bank; UINT16 m_mask; address_space &cpu_space() const; void point_specific_bank(const sam_bank *bank, UINT16 offset, UINT16 mask, memory_bank *&memory_bank, INT32 addrstart, INT32 addrend, bool is_write); }; // incidentals address_space * m_cpu_space; devcb2_read8 m_read_res; sam_bank m_banks[8]; sam_space<0x0000, 0x7FFF> m_space_0000; sam_space<0x8000, 0x9FFF> m_space_8000; sam_space<0xA000, 0xBFFF> m_space_A000; sam_space<0xC000, 0xFEFF> m_space_C000; sam_space<0xFF00, 0xFF1F> m_space_FF00; sam_space<0xFF20, 0xFF3F> m_space_FF20; sam_space<0xFF40, 0xFF5F> m_space_FF40; sam_space<0xFF60, 0xFFBF> m_space_FF60; sam_space<0xFFE0, 0xFFFF> m_space_FFE0; UINT16 m_counter_mask; UINT16 m_counter_or; // SAM state UINT16 m_counter; UINT8 m_counter_xdiv; UINT8 m_counter_ydiv; // dummy scratch memory UINT8 m_dummy[0x8000]; // typically called by CPU DECLARE_READ8_MEMBER( read ); DECLARE_WRITE8_MEMBER( write ); // called when there is a carry out of bit 3 on the counter ATTR_FORCE_INLINE void counter_carry_bit3(void) { UINT8 x_division; switch((m_sam_state & (SAM_STATE_V2|SAM_STATE_V1|SAM_STATE_V0)) / SAM_STATE_V0) { case 0x00: x_division = 1; break; case 0x01: x_division = 3; break; case 0x02: x_division = 1; break; case 0x03: x_division = 2; break; case 0x04: x_division = 1; break; case 0x05: x_division = 1; break; case 0x06: x_division = 1; break; case 0x07: x_division = 1; break; default: fatalerror("Should not get here\n"); return; } if (++m_counter_xdiv >= x_division) { m_counter_xdiv = 0; m_counter ^= 0x0010; if ((m_counter & 0x0010) == 0x0000) counter_carry_bit4(); } } // called when there is a carry out of bit 4 on the counter ATTR_FORCE_INLINE void counter_carry_bit4(void) { UINT8 y_division; switch((m_sam_state & (SAM_STATE_V2|SAM_STATE_V1|SAM_STATE_V0)) / SAM_STATE_V0) { case 0x00: y_division = 12; break; case 0x01: y_division = 1; break; case 0x02: y_division = 3; break; case 0x03: y_division = 1; break; case 0x04: y_division = 2; break; case 0x05: y_division = 1; break; case 0x06: y_division = 1; break; case 0x07: y_division = 1; break; default: fatalerror("Should not get here\n"); return; } if (++m_counter_ydiv >= y_division) { m_counter_ydiv = 0; m_counter += 0x0020; } } // other members void configure_bank(int bank, UINT8 *memory, UINT32 memory_size, bool is_read_only, read8_delegate rhandler, write8_delegate whandler); void horizontal_sync(void); void update_state(void); void update_memory(void); }; extern const device_type SAM6883; #endif /* __6883SAM__ */