// license:BSD-3-Clause
// copyright-holders:Karl Stenerud
/* ======================================================================== */
/* =============================== COPYRIGHT ============================== */
/* ======================================================================== */
/*

G65C816 CPU Emulator V1.00

Copyright Karl Stenerud
All rights reserved.

*/
/* ======================================================================== */
/* ================================= NOTES ================================ */
/* ======================================================================== */
/*

Changes:
    1.01 (2010-04-04):
        Angelo Salese
        - Added boundary checks for MVP and MVN in M mode.

    1.00 (2008-11-27):
        R. Belmont
        - Reworked for modern MAME

    0.94 (2007-06-14):
            Zsolt Vasvari
            - Removed unnecessary checks from MVP and MVN

    0.93 (2003-07-05):
            Angelo Salese
            - Fixed the BCD conversion when using the Decimal Flag in ADC and SBC.
            - Removed the two conversion tables for ADC and SBC as they aren't
              needed anymore.

    0.92 (2000-05-28):
            Lee Hammerton <lee-hammerton@hammerhead.ltd.uk>
            - Fixed debugger bug that caused D to be misrepresented.
            - Fixed MVN and MVP (they were reversed)

    0.91 (2000-05-22):
            Lee Hammerton <lee-hammerton@hammerhead.ltd.uk>
            - Fixed reset vector fetch to be little endian
            - Fixed disassembler call bug
            - Fixed C flag in SBC (should be inverted before operation)
            - Fixed JSR to stack PC-1 and RTS to pull PC and add 1

            Karl Stenerud <karl@higashiyama-unet.ocn.ne.jp>
            - Added correct timing for absolute indexed operations
            - SBC: fixed corruption of interim values

    0.90 (2000-05-17):
            Karl Stenerud <karl@higashiyama-unet.ocn.ne.jp>
            - first public release


Note on timings:
    - For instructions that write to memory (ASL, ASR, LSL, ROL, ROR, DEC,
      INC, STA, STZ), the absolute indexed addressing mode takes 1 extra
      cycle to complete.
    - The spec says fc (JMP axi) is 6 cyles, but elsewhere says 8 cycles
      (which is what it should be)


TODO general:
    - WAI will not stop if RDY is held high.

    - RDY internally held low when WAI executed and returned to hi when RES,
      ABORT, NMI, or IRQ asserted.

    - ABORT will terminate WAI instruction but wil not restart the processor

    - If interrupt occurs after ABORT of WAI, processor returns to WAI
      instruction.

    - Add one cycle when indexing across page boundary and E=1 except for STA
      and STZ instructions.

    - Add 1 cycle if branch is taken. In Emulation (E= 1 ) mode only --add 1
      cycle if the branch is taken and crosses a page boundary.

    - Add 1 cycle in Emulation mode (E=1) for (dir),y; abs,x; and abs,y
      addressing modes.

*/
/* ======================================================================== */
/* ================================= DATA ================================= */
/* ======================================================================== */

#include "emu.h"
#include "g65816.h"


DEFINE_DEVICE_TYPE(G65816, g65816_device, "g65c816", "G65C816")
DEFINE_DEVICE_TYPE(_5A22,  _5a22_device,  "5a22",    "5A22")

enum
{
	CPU_TYPE_G65816 = 0,
	CPU_TYPE_5A22 = 1
};


g65816_device::g65816_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
	: g65816_device(mconfig, G65816, tag, owner, clock, CPU_TYPE_G65816, address_map_constructor())
{
}


g65816_device::g65816_device(const machine_config &mconfig, device_type type, const char *tag, device_t *owner, uint32_t clock, int cpu_type, address_map_constructor internal)
	: cpu_device(mconfig, type, tag, owner, clock)
	, m_program_config("program", ENDIANNESS_LITTLE, 8, 24, 0, internal)
	, m_cpu_type(cpu_type)
{
}


device_memory_interface::space_config_vector g65816_device::memory_space_config() const
{
	return space_config_vector {
		std::make_pair(AS_PROGRAM, &m_program_config)
	};
}


ADDRESS_MAP_START(_5a22_device::_5a22_map)
	AM_RANGE(0x4202, 0x4202) AM_MIRROR(0xbf0000) AM_WRITE(wrmpya_w)
	AM_RANGE(0x4203, 0x4203) AM_MIRROR(0xbf0000) AM_WRITE(wrmpyb_w)
	AM_RANGE(0x4204, 0x4204) AM_MIRROR(0xbf0000) AM_WRITE(wrdivl_w)
	AM_RANGE(0x4205, 0x4205) AM_MIRROR(0xbf0000) AM_WRITE(wrdivh_w)
	AM_RANGE(0x4206, 0x4206) AM_MIRROR(0xbf0000) AM_WRITE(wrdvdd_w)

	AM_RANGE(0x420d, 0x420d) AM_MIRROR(0xbf0000) AM_WRITE(memsel_w)

	AM_RANGE(0x4214, 0x4214) AM_MIRROR(0xbf0000) AM_READ(rddivl_r)
	AM_RANGE(0x4215, 0x4215) AM_MIRROR(0xbf0000) AM_READ(rddivh_r)
	AM_RANGE(0x4216, 0x4216) AM_MIRROR(0xbf0000) AM_READ(rdmpyl_r)
	AM_RANGE(0x4217, 0x4217) AM_MIRROR(0xbf0000) AM_READ(rdmpyh_r)
ADDRESS_MAP_END


_5a22_device::_5a22_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
	: g65816_device(mconfig, _5A22, tag, owner, clock, CPU_TYPE_5A22, address_map_constructor(FUNC(_5a22_device::_5a22_map), this))
{
}


void g65816_device::g65816i_set_execution_mode(unsigned mode)
{
	assert(mode < 5);
	switch (mode)
	{
		case 0: FTABLE_OPCODES = g65816i_opcodes_M0X0; break;
		case 1: FTABLE_OPCODES = g65816i_opcodes_M0X1; break;
		case 2: FTABLE_OPCODES = g65816i_opcodes_M1X0; break;
		case 3: FTABLE_OPCODES = g65816i_opcodes_M1X1; break;
		case 4: FTABLE_OPCODES = g65816i_opcodes_E; break;
	}
	FTABLE_GET_REG = s_g65816_get_reg[mode];
	FTABLE_SET_REG = s_g65816_set_reg[mode];
	FTABLE_SET_LINE = s_g65816_set_line[mode];
	FTABLE_EXECUTE = s_g65816_execute[mode];
}


const g65816_device::get_reg_func g65816_device::s_g65816_get_reg[5] =
{
	&g65816_device::g65816i_get_reg_M0X0,
	&g65816_device::g65816i_get_reg_M0X1,
	&g65816_device::g65816i_get_reg_M1X0,
	&g65816_device::g65816i_get_reg_M1X1,
	&g65816_device::g65816i_get_reg_E
};

const g65816_device::set_reg_func g65816_device::s_g65816_set_reg[5] =
{
	&g65816_device::g65816i_set_reg_M0X0,
	&g65816_device::g65816i_set_reg_M0X1,
	&g65816_device::g65816i_set_reg_M1X0,
	&g65816_device::g65816i_set_reg_M1X1,
	&g65816_device::g65816i_set_reg_E
};

const g65816_device::set_line_func g65816_device::s_g65816_set_line[5] =
{
	&g65816_device::g65816i_set_line_M0X0,
	&g65816_device::g65816i_set_line_M0X1,
	&g65816_device::g65816i_set_line_M1X0,
	&g65816_device::g65816i_set_line_M1X1,
	&g65816_device::g65816i_set_line_E
};

const g65816_device::execute_func g65816_device::s_g65816_execute[5] =
{
	&g65816_device::g65816i_execute_M0X0,
	&g65816_device::g65816i_execute_M0X1,
	&g65816_device::g65816i_execute_M1X0,
	&g65816_device::g65816i_execute_M1X1,
	&g65816_device::g65816i_execute_E
};


/* ======================================================================== */
/* ================================= MEMORY =============================== */
/* ======================================================================== */

#define ADDRESS_65816(A) ((A)&0x00ffffff)

unsigned g65816_device::g65816i_read_8_normal(unsigned address)
{
	address = ADDRESS_65816(address);
	CLOCKS -= (bus_5A22_cycle_burst(address));
	return g65816_read_8(address);
}

unsigned g65816_device::g65816i_read_8_immediate(unsigned address)
{
	address = ADDRESS_65816(address);
	CLOCKS -= (bus_5A22_cycle_burst(address));
	return g65816_read_8_immediate(address);
}

unsigned g65816_device::g65816i_read_8_direct(unsigned address)
{
	if (FLAG_E)
	{
		/* force address into zero page */
		address = REGISTER_D + MAKE_UINT_8(address - REGISTER_D);
		CLOCKS -= (bus_5A22_cycle_burst(address));
	}
	else
	{
		address = ADDRESS_65816(address);
		CLOCKS -= (bus_5A22_cycle_burst(address));
	}
	return g65816_read_8(address);
}

unsigned g65816_device::g65816i_read_8_vector(unsigned address)
{
	if (!READ_VECTOR.isnull())
		return READ_VECTOR(*m_program, address, 0xff);
	else
		return g65816i_read_8_normal(address);
}

void g65816_device::g65816i_write_8_normal(unsigned address, unsigned value)
{
	address = ADDRESS_65816(address);
	CLOCKS -= (bus_5A22_cycle_burst(address));
	g65816_write_8(address, MAKE_UINT_8(value));
}

void g65816_device::g65816i_write_8_direct(unsigned address, unsigned value)
{
	if (FLAG_E)
	{
		/* force address into zero page */
		address = REGISTER_D + MAKE_UINT_8(address - REGISTER_D);
		CLOCKS -= (bus_5A22_cycle_burst(address));
	}
	else
	{
		address = ADDRESS_65816(address);
		CLOCKS -= (bus_5A22_cycle_burst(address));
	}
	g65816_write_8(address, MAKE_UINT_8(value));
}

unsigned g65816_device::g65816i_read_16_normal(unsigned address)
{
	return   g65816i_read_8_normal(address) |
			(g65816i_read_8_normal(address+1)<<8);
}

unsigned g65816_device::g65816i_read_16_immediate(unsigned address)
{
	return   g65816i_read_8_immediate(address) |
			(g65816i_read_8_immediate(address+1)<<8);
}

unsigned g65816_device::g65816i_read_16_direct(unsigned address)
{
	return   g65816i_read_8_direct(address) |
			(g65816i_read_8_direct(address+1)<<8);
}

unsigned g65816_device::g65816i_read_16_vector(unsigned address)
{
	return   g65816i_read_8_vector(address) |
			(g65816i_read_8_vector(address+1)<<8);
}

void g65816_device::g65816i_write_16_normal(unsigned address, unsigned value)
{
	g65816i_write_8_normal(address, value&0xff);
	g65816i_write_8_normal(address+1, value>>8);
}

void g65816_device::g65816i_write_16_direct(unsigned address, unsigned value)
{
	g65816i_write_8_direct(address, value&0xff);
	g65816i_write_8_direct(address+1, value>>8);
}

unsigned g65816_device::g65816i_read_24_normal(unsigned address)
{
	return   g65816i_read_8_normal(address)       |
			(g65816i_read_8_normal(address+1)<<8) |
			(g65816i_read_8_normal(address+2)<<16);
}

unsigned g65816_device::g65816i_read_24_immediate(unsigned address)
{
	return   g65816i_read_8_immediate(address)       |
			(g65816i_read_8_immediate(address+1)<<8) |
			(g65816i_read_8_immediate(address+2)<<16);
}

unsigned g65816_device::g65816i_read_24_direct(unsigned address)
{
	return   g65816i_read_8_direct(address)         |
			(g65816i_read_8_direct(address+1)<<8) |
			(g65816i_read_8_direct(address+2)<<16);
}


/* ======================================================================== */
/* ================================= STACK ================================ */
/* ======================================================================== */

void g65816_device::g65816i_push_8(unsigned value)
{
	g65816i_write_8_normal(REGISTER_S, value);
	if (FLAG_E)
	{
		REGISTER_S = MAKE_UINT_8(REGISTER_S-1) | 0x100;
	}
	else
	{
		REGISTER_S = MAKE_UINT_16(REGISTER_S-1);
	}
}

unsigned g65816_device::g65816i_pull_8()
{
	if (FLAG_E)
	{
		REGISTER_S = MAKE_UINT_8(REGISTER_S+1) | 0x100;
	}
	else
	{
		REGISTER_S = MAKE_UINT_16(REGISTER_S+1);
	}
	return g65816i_read_8_normal(REGISTER_S);
}

void g65816_device::g65816i_push_16(unsigned value)
{
	g65816i_push_8(value>>8);
	g65816i_push_8(value&0xff);
}

unsigned g65816_device::g65816i_pull_16()
{
	unsigned res = g65816i_pull_8();
	return res | (g65816i_pull_8() << 8);
}

void g65816_device::g65816i_push_24(unsigned value)
{
	g65816i_push_8(value>>16);
	g65816i_push_8((value>>8)&0xff);
	g65816i_push_8(value&0xff);
}

unsigned g65816_device::g65816i_pull_24()
{
	unsigned res = g65816i_pull_8();
	res |= g65816i_pull_8() << 8;
	return ((res + 1) & 0xffff) | (g65816i_pull_8() << 16);
}


/* ======================================================================== */
/* ============================ PROGRAM COUNTER =========================== */
/* ======================================================================== */

void g65816_device::g65816i_jump_16(unsigned address)
{
	REGISTER_PC = MAKE_UINT_16(address);
	g65816i_jumping(REGISTER_PC);
}

void g65816_device::g65816i_jump_24(unsigned address)
{
	REGISTER_PB = address&0xff0000;
	REGISTER_PC = MAKE_UINT_16(address);
	g65816i_jumping(REGISTER_PC);
}

void g65816_device::g65816i_branch_8(unsigned offset)
{
	if (FLAG_E)
	{
		unsigned old_pc = REGISTER_PC;
		REGISTER_PC = MAKE_UINT_16(REGISTER_PC + MAKE_INT_8(offset));
		if((REGISTER_PC^old_pc)&0xff00)
			CLK(1);
	}
	else
	{
		REGISTER_PC = MAKE_UINT_16(REGISTER_PC + MAKE_INT_8(offset));
	}
	g65816i_branching(REGISTER_PC);
}

void g65816_device::g65816i_branch_16(unsigned offset)
{
	REGISTER_PC = MAKE_UINT_16(REGISTER_PC + offset);
	g65816i_branching(REGISTER_PC);
}


/* ======================================================================== */
/* ============================ STATUS REGISTER =========================== */
/* ======================================================================== */

void g65816_device::g65816i_set_flag_mx(unsigned value)
{
	if (FLAG_M)
	{
		if(!(value & FLAGPOS_M))
		{
			REGISTER_A |= REGISTER_B;
			REGISTER_B = 0;
			FLAG_M = MFLAG_CLEAR;
		}
	}
	else
	{
		if(value & FLAGPOS_M)
		{
			REGISTER_B = REGISTER_A & 0xff00;
			REGISTER_A = MAKE_UINT_8(REGISTER_A);
			FLAG_M = MFLAG_SET;
		}
	}
	if (FLAG_X)
	{
		if(!(value & FLAGPOS_X))
		{
			FLAG_X = XFLAG_CLEAR;
		}
	}
	else
	{
		if(value & FLAGPOS_X)
		{
			REGISTER_X = MAKE_UINT_8(REGISTER_X);
			REGISTER_Y = MAKE_UINT_8(REGISTER_Y);
			FLAG_X = XFLAG_SET;
		}
	}
	g65816i_set_execution_mode((FLAG_M>>4) | (FLAG_X>>4));
}

void g65816_device::g65816i_set_flag_e(unsigned value)
{
	if (FLAG_E)
	{
		if(!value)
		{
			FLAG_E = EFLAG_CLEAR;
			g65816i_set_execution_mode(EXECUTION_MODE_M1X1);
		}
	}
	else
	{
		if(value)
		{
			if (!FLAG_M)
			{
				REGISTER_B = REGISTER_A & 0xff00;
				REGISTER_A &= 0x00ff;
				FLAG_M = MFLAG_SET;
			}
			if (!FLAG_X)
			{
				REGISTER_X = MAKE_UINT_8(REGISTER_X);
				REGISTER_Y = MAKE_UINT_8(REGISTER_Y);
				FLAG_X = XFLAG_SET;
			}
			REGISTER_S = MAKE_UINT_8(REGISTER_S) | 0x100;
			FLAG_E = EFLAG_SET;
			g65816i_set_execution_mode(EXECUTION_MODE_E);
		}
	}
}

void g65816_device::g65816i_set_flag_i(unsigned value)
{
	value &= FLAGPOS_I;
	if(!FLAG_I || value)
	{
		FLAG_I = value;
		return;
	}
	FLAG_I = value;
}

/* Get the Processor Status Register */
unsigned g65816_device::g65816i_get_reg_p()
{
	return  (FLAG_N&0x80)       |
			((FLAG_V>>1)&0x40)  |
			FLAG_M              |
			FLAG_X              |
			FLAG_D              |
			FLAG_I              |
			((!FLAG_Z)<<1)      |
			((FLAG_C>>8)&1);
}

void g65816_device::g65816i_set_reg_p(unsigned value)
{
	if (FLAG_E)
	{
		FLAG_N = value;
		FLAG_V = value << 1;
		FLAG_D = value & FLAGPOS_D;
		FLAG_Z = !(value & FLAGPOS_Z);
		FLAG_C = value << 8;
		g65816i_set_flag_i(value);
	}
	else
	{
		FLAG_N = value;
		FLAG_V = value << 1;
		FLAG_D = value & FLAGPOS_D;
		FLAG_Z = !(value & FLAGPOS_Z);
		FLAG_C = value << 8;
		g65816i_set_flag_mx(value);
		g65816i_set_flag_i(value);
	}
}


/* ======================================================================== */
/* =============================== INTERRUPTS ============================= */
/* ======================================================================== */

void g65816_device::g65816i_interrupt_hardware(unsigned vector)
{
	if (FLAG_E)
	{
		CLK(7);
		g65816i_push_16(REGISTER_PC);
		g65816i_push_8(g65816i_get_reg_p() & ~FLAGPOS_B);
		FLAG_D = DFLAG_CLEAR;
		g65816i_set_flag_i(IFLAG_SET);
		REGISTER_PB = 0;
		g65816i_jump_16(g65816i_read_16_vector(vector));
		standard_irq_callback(0);
	}
	else
	{
		CLK(8);
		g65816i_push_8(REGISTER_PB>>16);
		g65816i_push_16(REGISTER_PC);
		g65816i_push_8(g65816i_get_reg_p());
		FLAG_D = DFLAG_CLEAR;
		g65816i_set_flag_i(IFLAG_SET);
		REGISTER_PB = 0;
		g65816i_jump_16(g65816i_read_16_vector(vector));
		standard_irq_callback(0);
	}
}

void g65816_device::g65816i_interrupt_software(unsigned vector)
{
	if (FLAG_E)
	{
		CLK(7);
		g65816i_push_16(REGISTER_PC);
		g65816i_push_8(g65816i_get_reg_p());
		FLAG_D = DFLAG_CLEAR;
		g65816i_set_flag_i(IFLAG_SET);
		REGISTER_PB = 0;
		g65816i_jump_16(g65816i_read_16_normal(vector));
	}
	else
	{
		CLK(8);
		g65816i_push_8(REGISTER_PB>>16);
		g65816i_push_16(REGISTER_PC);
		g65816i_push_8(g65816i_get_reg_p());
		FLAG_D = DFLAG_CLEAR;
		g65816i_set_flag_i(IFLAG_SET);
		REGISTER_PB = 0;
		g65816i_jump_16(g65816i_read_16_normal(vector));
	}
}

void g65816_device::g65816i_interrupt_nmi()
{
	if (FLAG_E)
	{
		CLK(7);
		g65816i_push_16(REGISTER_PC);
		g65816i_push_8(g65816i_get_reg_p() & ~FLAGPOS_B);
		FLAG_D = DFLAG_CLEAR;
		REGISTER_PB = 0;
		g65816i_jump_16(g65816i_read_16_normal((FLAG_E) ? VECTOR_NMI_E : VECTOR_NMI_N));
	}
	else
	{
		CLK(8);
		g65816i_push_8(REGISTER_PB>>16);
		g65816i_push_16(REGISTER_PC);
		g65816i_push_8(g65816i_get_reg_p());
		FLAG_D = DFLAG_CLEAR;
		REGISTER_PB = 0;
		g65816i_jump_16(g65816i_read_16_normal((FLAG_E) ? VECTOR_NMI_E : VECTOR_NMI_N));
	}
}


void g65816_device::g65816i_check_maskable_interrupt()
{
	if(!(CPU_STOPPED & STOP_LEVEL_STOP) && LINE_IRQ && !FLAG_I)
	{
		g65816i_interrupt_hardware((FLAG_E) ? VECTOR_IRQ_E : VECTOR_IRQ_N);
		CPU_STOPPED &= ~STOP_LEVEL_WAI;
		LINE_IRQ=0;
	}
}


unsigned g65816_device::EA_IMM8()  {REGISTER_PC += 1; return REGISTER_PB | MAKE_UINT_16(REGISTER_PC-1);}
unsigned g65816_device::EA_IMM16() {REGISTER_PC += 2; return REGISTER_PB | MAKE_UINT_16(REGISTER_PC-2);}
unsigned g65816_device::EA_IMM24() {REGISTER_PC += 3; return REGISTER_PB | MAKE_UINT_16(REGISTER_PC-3);}
unsigned g65816_device::EA_D()     {if(MAKE_UINT_8(REGISTER_D)) CLK(1); return MAKE_UINT_16(REGISTER_D + g65816i_read_8_immediate(EA_IMM8()));}
unsigned g65816_device::EA_A()     {return REGISTER_DB | g65816i_read_16_immediate(EA_IMM16());}
unsigned g65816_device::EA_AL()    {return g65816i_read_24_immediate(EA_IMM24());}
unsigned g65816_device::EA_DX()    {return MAKE_UINT_16(REGISTER_D + g65816i_read_8_immediate(EA_IMM8()) + REGISTER_X);}
unsigned g65816_device::EA_DY()    {return MAKE_UINT_16(REGISTER_D + g65816i_read_8_immediate(EA_IMM8()) + REGISTER_Y);}
unsigned g65816_device::EA_AX()    {unsigned tmp = EA_A(); if((tmp^(tmp+REGISTER_X))&0xff00) CLK(1); return tmp + REGISTER_X;}
unsigned g65816_device::EA_ALX()   {return EA_AL() + REGISTER_X;}
unsigned g65816_device::EA_AY()    {unsigned tmp = EA_A(); if((tmp^(tmp+REGISTER_X))&0xff00) CLK(1); return tmp + REGISTER_Y;}
unsigned g65816_device::EA_DI()    {return REGISTER_DB | g65816i_read_16_direct(EA_D());}
unsigned g65816_device::EA_DLI()   {return g65816i_read_24_direct(EA_D());}
unsigned g65816_device::EA_AI()    {return g65816i_read_16_normal(g65816i_read_16_immediate(EA_IMM16()));}
unsigned g65816_device::EA_ALI()   {return g65816i_read_24_normal(EA_A());}
unsigned g65816_device::EA_DXI()   {return REGISTER_DB | g65816i_read_16_direct(EA_DX());}
unsigned g65816_device::EA_DIY()   {unsigned tmp = REGISTER_DB | g65816i_read_16_direct(EA_D()); if((tmp^(tmp+REGISTER_X))&0xff00) CLK(1); return tmp + REGISTER_Y;}
unsigned g65816_device::EA_DLIY()  {return g65816i_read_24_direct(EA_D()) + REGISTER_Y;}
unsigned g65816_device::EA_AXI()   {return g65816i_read_16_normal(MAKE_UINT_16(g65816i_read_16_immediate(EA_IMM16()) + REGISTER_X));}
unsigned g65816_device::EA_S()     {return MAKE_UINT_16(REGISTER_S + g65816i_read_8_immediate(EA_IMM8()));}
unsigned g65816_device::EA_SIY()   {return MAKE_UINT_16(g65816i_read_16_normal(REGISTER_S + g65816i_read_8_immediate(EA_IMM8())) + REGISTER_Y) | REGISTER_DB;}



/* ======================================================================== */
/* ================================= API ================================== */
/* ======================================================================== */


void g65816_device::device_reset()
{
	/* Start the CPU */
	CPU_STOPPED = 0;

	/* Put into emulation mode */
	REGISTER_D = 0;
	REGISTER_PB = 0;
	REGISTER_DB = 0;
	REGISTER_S = (REGISTER_S & 0xff) | 0x100;
	REGISTER_X &= 0xff;
	REGISTER_Y &= 0xff;
	if(!FLAG_M)
	{
		REGISTER_B = REGISTER_A & 0xff00;
		REGISTER_A &= 0xff;
	}
	FLAG_E = EFLAG_SET;
	FLAG_M = MFLAG_SET;
	FLAG_X = XFLAG_SET;

	/* Clear D and set I */
	FLAG_D = DFLAG_CLEAR;
	FLAG_I = IFLAG_SET;

	/* Clear all pending interrupts (should we really do this?) */
	LINE_IRQ = 0;
	LINE_NMI = 0;
	IRQ_DELAY = 0;

	/* Set the function tables to emulation mode */
	g65816i_set_execution_mode(EXECUTION_MODE_E);

	/* 6502 expects these, but its not in the 65816 spec */
	FLAG_Z = ZFLAG_CLEAR;
	REGISTER_S = 0x1ff;

	/* Fetch the reset vector */
	REGISTER_PC = g65816_read_8(VECTOR_RESET) | (g65816_read_8(VECTOR_RESET+1)<<8);
	g65816i_jumping(REGISTER_PB | REGISTER_PC);
}


/* Execute some instructions */
void g65816_device::execute_run()
{
	int clocks = m_ICount;
	m_ICount = clocks - (this->*FTABLE_EXECUTE)(m_ICount);
}


/* Get the current Program Counter */
unsigned g65816_device::g65816_get_pc()
{
	return REGISTER_PB | REGISTER_PC;
}

/* Set the Program Counter */
void g65816_device::g65816_set_pc(unsigned val)
{
	REGISTER_PC = MAKE_UINT_16(val);
	REGISTER_PB = (val >> 16) & 0xFF;
	g65816_jumping(REGISTER_PB | REGISTER_PC);
}

/* Get the current Stack Pointer */
unsigned g65816_device::g65816_get_sp()
{
	return REGISTER_S;
}

/* Set the Stack Pointer */
void g65816_device::g65816_set_sp(unsigned val)
{
	REGISTER_S = FLAG_E ? MAKE_UINT_8(val) | 0x100 : MAKE_UINT_16(val);
}

/* Get a register */
unsigned g65816_device::g65816_get_reg(int regnum)
{
	/* Set the function tables to emulation mode if the FTABLE is nullptr */
	if( FTABLE_GET_REG == nullptr )
		g65816i_set_execution_mode(EXECUTION_MODE_E);

	return (this->*FTABLE_GET_REG)(regnum);
}

/* Set a register */
void g65816_device::g65816_set_reg(int regnum, unsigned value)
{
	(this->*FTABLE_SET_REG)(regnum, value);
}

/* Set an interrupt line */
void g65816_device::execute_set_input(int line, int state)
{
	(this->*FTABLE_SET_LINE)(line, state);
}

util::disasm_interface *g65816_device::create_disassembler()
{
	return new g65816_disassembler(this);
}

bool g65816_device::get_m_flag() const
{
	return FLAG_M;
}

bool g65816_device::get_x_flag() const
{
	return FLAG_X;
}

void g65816_device::g65816_restore_state()
{
	// restore proper function pointers
	g65816i_set_execution_mode((FLAG_M>>4) | (FLAG_X>>4));

	// make sure the memory system can keep up
	g65816i_jumping(REGISTER_PB | REGISTER_PC);
}

void g65816_device::device_start()
{
	m_a = 0;
	m_b = 0;
	m_x = 0;
	m_y = 0;
	m_s = 0;
	m_pc = 0;
	m_ppc = 0;
	m_pb = 0;
	m_db = 0;
	m_d = 0;
	m_flag_e = 0;
	m_flag_m = 0;
	m_flag_x = 0;
	m_flag_n = 0;
	m_flag_v = 0;
	m_flag_d = 0;
	m_flag_i = 0;
	m_flag_z = 0;
	m_flag_c = 0;
	m_line_irq = 0;
	m_line_nmi = 0;
	m_fastROM = 0;
	m_ir = 0;
	m_irq_delay = 0;
	m_stopped = 0;
	m_source = 0;
	m_destination = 0;
	m_wrmpya = 0;
	m_wrmpyb = 0;
	m_rdmpy = 0;
	m_wrdiv = 0;
	m_dvdd = 0;
	m_rddiv = 0;
	m_opcodes = nullptr;
	m_get_reg = nullptr;
	m_set_reg = nullptr;
	m_set_line = nullptr;
	m_execute = nullptr;
	m_debugger_temp = 0;

	m_program = &space(AS_PROGRAM);

	save_item(NAME(m_a));
	save_item(NAME(m_b));
	save_item(NAME(m_x));
	save_item(NAME(m_y));
	save_item(NAME(m_s));
	save_item(NAME(m_pc));
	save_item(NAME(m_ppc));
	save_item(NAME(m_pb));
	save_item(NAME(m_db));
	save_item(NAME(m_d));
	save_item(NAME(m_flag_e));
	save_item(NAME(m_flag_m));
	save_item(NAME(m_flag_x));
	save_item(NAME(m_flag_n));
	save_item(NAME(m_flag_v));
	save_item(NAME(m_flag_d));
	save_item(NAME(m_flag_i));
	save_item(NAME(m_flag_z));
	save_item(NAME(m_flag_c));
	save_item(NAME(m_line_irq));
	save_item(NAME(m_line_nmi));
	save_item(NAME(m_ir));
	save_item(NAME(m_irq_delay));
	save_item(NAME(m_stopped));
	save_item(NAME(m_fastROM));

	machine().save().register_postload(save_prepost_delegate(FUNC(g65816_device::g65816_restore_state), this));

	m_rw8_cycles = 1;
	m_rw16_cycles = 2;
	m_rw24_cycles = 3;

	state_add( G65816_PC,        "PC", m_debugger_temp).callimport().callexport().formatstr("%06X");
	state_add( G65816_S,         "S", m_s).callimport().formatstr("%04X");
	state_add( G65816_P,         "P", m_debugger_temp).callimport().callexport().formatstr("%02X");
	state_add( G65816_A,         "A", m_debugger_temp).callimport().callexport().formatstr("%04X");
	state_add( G65816_X,         "X", m_x).callimport().formatstr("%04X");
	state_add( G65816_Y,         "Y", m_y).callimport().formatstr("%04X");
	state_add( G65816_PB,        "PB", m_debugger_temp).callimport().callexport().formatstr("%02X");
	state_add( G65816_DB,        "DB", m_debugger_temp).callimport().callexport().formatstr("%02X");
	state_add( G65816_D,         "D", m_d).callimport().formatstr("%04X");
	state_add( G65816_E,         "E", m_flag_e).mask(0x01).callimport().formatstr("%01X");
	state_add( G65816_NMI_STATE, "NMI", m_line_nmi).mask(0x01).callimport().formatstr("%01X");
	state_add( G65816_IRQ_STATE, "IRQ", m_line_irq).mask(0x01).callimport().formatstr("%01X");

	state_add( STATE_GENPC, "GENPC", m_debugger_temp).callimport().callexport().formatstr("%06X").noshow();
	state_add( STATE_GENPCBASE, "CURPC", m_debugger_temp).callimport().callexport().formatstr("%06X").noshow();
	state_add( STATE_GENSP, "GENSP", m_debugger_temp).callimport().callexport().formatstr("%06X").noshow();
	state_add( STATE_GENFLAGS, "GENFLAGS", m_debugger_temp).formatstr("%8s").noshow();

	m_icountptr = &m_ICount;
}

void g65816_device::state_import(const device_state_entry &entry)
{
	switch (entry.index())
	{
		case STATE_GENPC:
		case STATE_GENPCBASE:
			g65816_set_pc(m_debugger_temp);
			break;
		case STATE_GENSP:
			g65816_set_sp(m_debugger_temp);
			break;
		case G65816_PC:
		case G65816_PB:
		case G65816_DB:
			g65816_set_reg(entry.index(), m_debugger_temp);
			break;
		case G65816_D:
			g65816_set_reg(G65816_D, m_d);
			break;
		case G65816_S:
			g65816_set_reg(G65816_S, m_s);
			break;
		case G65816_P:
			g65816_set_reg(G65816_P, m_debugger_temp);
			break;
		case G65816_E:
			g65816_set_reg(G65816_E, m_flag_e);
			break;
		case G65816_A:
			g65816_set_reg(G65816_A, m_debugger_temp);
			break;
		case G65816_X:
			g65816_set_reg(G65816_X, m_x);
			break;
		case G65816_Y:
			g65816_set_reg(G65816_Y, m_y);
			break;
		case G65816_NMI_STATE:
			g65816_set_reg(G65816_NMI_STATE, m_line_nmi);
			break;
		case G65816_IRQ_STATE:
			g65816_set_reg(G65816_IRQ_STATE, m_line_irq);
			break;
	}
}

void g65816_device::state_export(const device_state_entry &entry)
{
	switch (entry.index())
	{
		case STATE_GENPC:
		case STATE_GENPCBASE:
		case G65816_PC:
			m_debugger_temp = g65816_get_pc();
			break;
		case STATE_GENSP:
			m_debugger_temp = g65816_get_sp();
			break;
		case G65816_PB:
			m_debugger_temp = m_pb>>16;
			break;
		case G65816_DB:
			m_debugger_temp = m_db>>16;
			break;
		case G65816_P:
			m_debugger_temp = (m_flag_n&0x80)         |
								((m_flag_v>>1)&0x40)    |
								m_flag_m                |
								m_flag_x                |
								m_flag_d                |
								m_flag_i                |
								((!m_flag_z)<<1)        |
								((m_flag_c>>8)&1);
			break;
		case G65816_A:
			m_debugger_temp = m_a | m_b;
			break;
	}
}

void g65816_device::state_string_export(const device_state_entry &entry, std::string &str) const
{
	switch (entry.index())
	{
		case STATE_GENFLAGS:
			str = string_format("%c%c%c%c%c%c%c%c",
				m_flag_n & NFLAG_SET ? 'N':'.',
				m_flag_v & VFLAG_SET ? 'V':'.',
				m_flag_m & MFLAG_SET ? 'M':'.',
				m_flag_x & XFLAG_SET ? 'X':'.',
				m_flag_d & DFLAG_SET ? 'D':'.',

				m_flag_i & IFLAG_SET ? 'I':'.',
				m_flag_z == 0        ? 'Z':'.',
				m_flag_c & CFLAG_SET ? 'C':'.');
			break;
	}
}

void g65816_device::set_read_vector_callback(read8_delegate read_vector)
{
	READ_VECTOR = read_vector;
}


/*
SNES specific, used to handle master cycles, based off byuu's BSNES code
*/

int g65816_device::bus_5A22_cycle_burst(unsigned addr)
{
	if(m_cpu_type == CPU_TYPE_G65816)
		return 0;

	if(addr & 0x408000) {
		if(addr & 0x800000)
			return (m_fastROM & 1) ? 6 : 8;

		return 8;
	}
	if((addr + 0x6000) & 0x4000) return 8;
	if((addr - 0x4000) & 0x7e00) return 6;

	return 12;
}


void _5a22_device::device_start()
{
	g65816_device::device_start();

	state_add( _5A22_FASTROM, "fastROM", m_debugger_temp).mask(0x01).callimport().callexport().formatstr("%01X");

	m_rw8_cycles = 0;
	m_rw16_cycles = 0;
	m_rw24_cycles = 0;
}

void _5a22_device::state_import(const device_state_entry &entry)
{
	switch (entry.index())
	{
		case _5A22_FASTROM:
			g65816_set_reg(_5A22_FASTROM, m_debugger_temp);
			break;
		default:
			g65816_device::state_import(entry);
			break;
	}
}

void _5a22_device::state_export(const device_state_entry &entry)
{
	switch (entry.index())
	{
		case _5A22_FASTROM:
			m_debugger_temp = g65816_get_reg(_5A22_FASTROM);
			break;
		default:
			g65816_device::state_export(entry);
			break;
	}
}

void _5a22_device::device_reset()
{
	g65816_device::device_reset();

	m_fastROM = 0;
	m_wrmpya = 0xff;
	m_wrdiv = 0xffff;
}

/* TODO: multiplication / division should actually occur inside CPU_EXECUTE */
/* (Old note, for reference): multiplication should take 8 CPU cycles &
division 16 CPU cycles, but using these timers breaks e.g. Chrono Trigger
intro and Super Tennis gameplay. On the other hand, timers are needed for the
translation of Breath of Fire 2 to work. More weirdness: we might need to leave
8 CPU cycles for division at first, since using 16 produces bugs (see e.g.
Triforce pieces in Zelda 3 intro) */

WRITE8_MEMBER( _5a22_device::wrmpya_w )
{
	m_wrmpya = data;
}

WRITE8_MEMBER( _5a22_device::wrmpyb_w )
{
	m_wrmpyb = data;
	m_rdmpy = m_wrmpya * m_wrmpyb;
	/* TODO: m_rddiv == 0? */
}

WRITE8_MEMBER( _5a22_device::wrdivl_w )
{
	m_wrdiv = (data) | (m_wrdiv & 0xff00);
}

WRITE8_MEMBER( _5a22_device::wrdivh_w )
{
	m_wrdiv = (data << 8) | (m_wrdiv & 0xff);
}

WRITE8_MEMBER( _5a22_device::wrdvdd_w )
{
	uint16_t quotient, remainder;

	m_dvdd = data;

	quotient = (m_dvdd == 0) ? 0xffff : m_wrdiv / m_dvdd;
	remainder = (m_dvdd == 0) ? 0x000c : m_wrdiv % m_dvdd;

	m_rddiv = quotient;
	m_rdmpy = remainder;
}

WRITE8_MEMBER( _5a22_device::memsel_w )
{
	m_fastROM = data & 1;
}

READ8_MEMBER( _5a22_device::rddivl_r )
{
	return m_rddiv & 0xff;
}

READ8_MEMBER( _5a22_device::rddivh_r )
{
	return m_rddiv >> 8;
}

READ8_MEMBER( _5a22_device::rdmpyl_r )
{
	return m_rdmpy & 0xff;
}

READ8_MEMBER( _5a22_device::rdmpyh_r )
{
	return m_rdmpy >> 8;
}


void _5a22_device::set_5a22_map()
{
	space(AS_PROGRAM).install_write_handler(0x4202, 0x4202, 0, 0xbf0000, 0, write8_delegate(FUNC(_5a22_device::wrmpya_w),this));
	space(AS_PROGRAM).install_write_handler(0x4203, 0x4203, 0, 0xbf0000, 0, write8_delegate(FUNC(_5a22_device::wrmpyb_w),this));
	space(AS_PROGRAM).install_write_handler(0x4204, 0x4204, 0, 0xbf0000, 0, write8_delegate(FUNC(_5a22_device::wrdivl_w),this));
	space(AS_PROGRAM).install_write_handler(0x4205, 0x4205, 0, 0xbf0000, 0, write8_delegate(FUNC(_5a22_device::wrdivh_w),this));
	space(AS_PROGRAM).install_write_handler(0x4206, 0x4206, 0, 0xbf0000, 0, write8_delegate(FUNC(_5a22_device::wrdvdd_w),this));

	space(AS_PROGRAM).install_write_handler(0x420d, 0x420d, 0, 0xbf0000, 0, write8_delegate(FUNC(_5a22_device::memsel_w),this));

	space(AS_PROGRAM).install_read_handler(0x4214, 0x4214, 0, 0xbf0000, 0, read8_delegate(FUNC(_5a22_device::rddivl_r),this));
	space(AS_PROGRAM).install_read_handler(0x4215, 0x4215, 0, 0xbf0000, 0, read8_delegate(FUNC(_5a22_device::rddivh_r),this));
	space(AS_PROGRAM).install_read_handler(0x4216, 0x4216, 0, 0xbf0000, 0, read8_delegate(FUNC(_5a22_device::rdmpyl_r),this));
	space(AS_PROGRAM).install_read_handler(0x4217, 0x4217, 0, 0xbf0000, 0, read8_delegate(FUNC(_5a22_device::rdmpyh_r),this));
}


/* ======================================================================== */
/* ============================== END OF FILE ============================= */
/* ======================================================================== */
