text: /*****************************************************************************
   *
   *	 m6509.c
   *	 Portable 6509 emulator V1.0beta1
   *
   *	 Copyright (c) 2000 Peter Trauner, all rights reserved.
   *	 documentation by vice emulator team
   *
   *	 - This source code is released as freeware for non-commercial purposes.
   *	 - You are free to use and redistribute this code in modified or
   *	   unmodified form, provided you list me in the credits.
   *	 - If you modify this source code, you must add a notice to each modified
   *	   source file that it has been changed.  If you're a nice person, you
   *	   will clearly mark each change too.  :)
   *	 - If you wish to use this for commercial purposes, please contact me at
   *	   pullmoll@t-online.de
   *	 - The author of this copywritten work reserves the right to change the
   *	   terms of its usage and license at any time, including retroactively
   *	 - This entire notice must remain in the source code.
   *
   *****************************************************************************/
  /*
    2000 March 10 PeT added SO input line
  
  The basic difference is the amount of RAM these machines have been supplied with. The B128 and the CBM *10
  models had 128k RAM, the others 256k. This implies some banking scheme, as the 6502 can only address 64k. And
  indeed those machines use a 6509, that can address 1 MByte of RAM. It has 2 registers at addresses 0 and 1. The
  indirect bank register at address 1 determines the bank (0-15) where the opcodes LDA (zp),Y and STA (zp),Y
  take the data from. The exec bank register at address 0 determines the bank where all other read and write
  addresses take place.
  
   vice writes to bank register only with zeropage operand
   0, 1 are bank register in all banks
  
   lda  (zp),y
   sta  (zp),y
  
  */
  
  #include <stdio.h>
  #include "driver.h"
  #include "state.h"
  #include "mamedbg.h"
  #include "m6509.h"
  #include "m6502.h"
  
  #include "ops02.h"
  #include "ill02.h"
  #include "ops09.h"
  
  #define CORE_M6509
  
  #define M6502_NMI_VEC	0xfffa
  #define M6502_RST_VEC	0xfffc
  #define M6502_IRQ_VEC	0xfffe
  #define M6509_RST_VEC	M6502_RST_VEC
  #define M6509_IRQ_VEC	M6502_IRQ_VEC
  #define M6509_NMI_VEC	M6502_NMI_VEC
  
  #ifdef RUNTIME_LOADER
  struct cpu_interface
  m6509_interface=
  CPU0(M6509,    m6509,    1,  0,1.00,M6509_INT_NONE,    M6509_INT_IRQ,  M6509_INT_NMI,  8, 20,     0,20,LE,1, 3 );
  
  extern void m6509_runtime_loader_init(void)
  {
  	cpuintf[CPU_M6509]=m6509_interface;
  }
  #endif
  
  
  /* Layout of the registers in the debugger */
  static UINT8 m6509_reg_layout[] = {
  	M6509_A,M6509_X,M6509_Y,M6509_S,M6509_PC, M6509_P,-1,
  	M6509_PC_BANK, M6509_IND_BANK, M6509_EA, M6509_ZP, -1,
  	M6509_NMI_STATE, M6509_IRQ_STATE, M6509_SO_STATE, 0
  };
  
  /* Layout of the debugger windows x,y,w,h */
  static UINT8 m6509_win_layout[] = {
  	25, 0,55, 3,	/* register window (top, right rows) */
  	 0, 0,24,22,	/* disassembler window (left colums) */
  	25, 4,55, 8,	/* memory #1 window (right, upper middle) */
  	25,13,55, 9,	/* memory #2 window (right, lower middle) */
  	 0,23,80, 1,	/* command line window (bottom rows) */
  };
  
  typedef struct {
  	UINT8	subtype;		/* currently selected cpu sub type */
  	void	(**insn)(void); /* pointer to the function pointer table */
  	PAIR	ppc;			/* previous program counter */
  	/* pc.w.h contains the current page pc_bank.w.h for better speed */
  	PAIR	pc; 			/* program counter */
  	PAIR	sp; 			/* stack pointer (always 100 - 1FF) */
  	PAIR	zp; 			/* zero page address */
  	PAIR	ea; 			/* effective address */
  	UINT8	a;				/* Accumulator */
  	UINT8	x;				/* X index register */
  	UINT8	y;				/* Y index register */
  	PAIR   pc_bank; 	   /* 4 bits, addressed over address 0 */
  	PAIR   ind_bank;	   /* 4 bits, addressed over address 1 */
  	UINT8	p;				/* Processor status */
  	UINT8	pending_irq;	/* nonzero if an IRQ is pending */
  	UINT8	after_cli;		/* pending IRQ and last insn cleared I */
  	UINT8	nmi_state;
  	UINT8	irq_state;
  	UINT8	so_state;
  	int 	(*irq_callback)(int irqline);	/* IRQ callback */
  }	m6509_Regs;
  
  int m6509_ICount = 0;
  
  static m6509_Regs m6509;
  
  /***************************************************************
   * include the opcode macros, functions and tables
   ***************************************************************/
  
  #include "t6509.c"
  
  READ_HANDLER( m6509_read_00000 )
  {
  	return m6509.pc_bank.b.h2;
  }
  
  READ_HANDLER( m6509_read_00001 )
  {
  	return m6509.ind_bank.b.h2;
  }
  
  WRITE_HANDLER( m6509_write_00000 )
  {
  	m6509.pc_bank.b.h2=data&0xf;
  	m6509.pc.w.h=m6509.pc_bank.w.h;
  	change_pc20(PCD);
  }
  
  WRITE_HANDLER( m6509_write_00001 )
  {
  	m6509.ind_bank.b.h2=data&0xf;
  }
  
  void m6509_reset (void *param)
  {
  	m6509.insn = insn6509;
  
  	m6509.pc_bank.d=m6509.ind_bank.d=0;
  	m6509.pc_bank.b.h2=m6509.ind_bank.b.h2=0xf; /* cbm500 needs this */
  	m6509.pc.w.h=m6509.pc_bank.w.h;
  	/* wipe out the rest of the m6509 structure */
  	/* read the reset vector into PC */
  	PCL = RDMEM(M6509_RST_VEC|PB);
  	PCH = RDMEM((M6509_RST_VEC+1)|PB);
  
  	m6509.sp.d = 0x01ff;
  	m6509.p = F_T|F_B|F_I|F_Z|(P&F_D);	/* set T, I and Z flags */
  	m6509.pending_irq = 0;	/* nonzero if an IRQ is pending */
  	m6509.after_cli = 0;	/* pending IRQ and last insn cleared I */
  	m6509.irq_callback = NULL;
  
  	change_pc20(PCD);
  }
  
  void m6509_exit(void)
  {
  	/* nothing to do yet */
  }
  
  unsigned m6509_get_context (void *dst)
  {
  	if( dst )
  		*(m6509_Regs*)dst = m6509;
  	return sizeof(m6509_Regs);
  }
  
  void m6509_set_context (void *src)
  {
  	if( src )
  	{
  		m6509 = *(m6509_Regs*)src;
  		change_pc20(PCD);
  	}
  }
  
  unsigned m6509_get_reg (int regnum)
  {
  	switch( regnum )
  	{
  		case REG_PC: return PCD;
  		case M6509_PC: return m6509.pc.d;
  		case REG_SP: return S;
  		case M6509_S: return m6509.sp.b.l;
  		case M6509_P: return m6509.p;
  		case M6509_A: return m6509.a;
  		case M6509_X: return m6509.x;
  		case M6509_Y: return m6509.y;
  		case M6509_PC_BANK: return m6509.pc_bank.b.h2;
  		case M6509_IND_BANK: return m6509.ind_bank.b.h2;
  		case M6509_EA: return m6509.ea.d;
  		case M6509_ZP: return m6509.zp.b.l;
  		case M6509_NMI_STATE: return m6509.nmi_state;
  		case M6509_IRQ_STATE: return m6509.irq_state;
  		case M6509_SO_STATE: return m6509.so_state;
  		case REG_PREVIOUSPC: return m6509.ppc.w.l;
  		default:
  			if( regnum <= REG_SP_CONTENTS )
  			{
  				unsigned offset = S + 2 * (REG_SP_CONTENTS - regnum);
  				if( offset < 0x1ff )
  					return RDMEM( offset ) | ( RDMEM( offset + 1 ) << 8 );
  			}
  	}
  	return 0;
  }
  
  void m6509_set_reg (int regnum, unsigned val)
  {
  	switch( regnum )
  	{
  		case REG_PC: PCW = val&0xffff; change_pc20(PCD); break;
  		case M6509_PC: m6509.pc.w.l = val; break;
  		case REG_SP: S = val; break;
  		case M6509_S: m6509.sp.b.l = val; break;
  		case M6509_P: m6509.p = val; break;
  		case M6509_A: m6509.a = val; break;
  		case M6509_X: m6509.x = val; break;
  		case M6509_Y: m6509.y = val; break;
  		case M6509_PC_BANK: m6509.pc_bank.b.h2 = val; break;
  		case M6509_IND_BANK: m6509.ind_bank.b.h2 = val; break;
  		case M6509_EA: m6509.ea.d = val; break;
  		case M6509_ZP: m6509.zp.b.l = val; break;
  		case M6509_NMI_STATE: m6509_set_irq_line( IRQ_LINE_NMI, val ); break;
  		case M6509_IRQ_STATE: m6509_set_irq_line( 0, val ); break;
  		case M6509_SO_STATE: m6509_set_irq_line( M6509_SET_OVERFLOW, val ); break;
  		default:
  			if( regnum <= REG_SP_CONTENTS )
  			{
  				unsigned offset = S + 2 * (REG_SP_CONTENTS - regnum);
  				if( offset < 0x1ff )
  				{
  					WRMEM( offset, val & 0xfff );
  					WRMEM( offset + 1, (val >> 8) & 0xff );
  				}
  			}
  	}
  }
  
  static INLINE void m6509_take_irq(void)
  {
  	if( !(P & F_I) )
  	{
  		EAD = M6509_IRQ_VEC;
  		EAWH = PBWH;
  		m6509_ICount -= 7;
  		PUSH(PCH);
  		PUSH(PCL);
  		PUSH(P & ~F_B);
  		P |= F_I;		/* knock out D and set I flag */
  		PCL = RDMEM(EAD);
  		PCH = RDMEM(EAD+1);
  		log_cb(RETRO_LOG_DEBUG, LOGPRE "M6509#%d takes IRQ ($%04x)\n", cpu_getactivecpu(), PCD);
  		/* call back the cpuintrf to let it clear the line */
  		if (m6509.irq_callback) (*m6509.irq_callback)(0);
  		change_pc20(PCD);
  	}
  	m6509.pending_irq = 0;
  }
  
  int m6509_execute(int cycles)
  {
  	m6509_ICount = cycles;
  
  	change_pc20(PCD);
  
  	do
  	{
  		UINT8 op;
  		PPC = PCD;
  
  		CALL_MAME_DEBUG;
  
  		/* if an irq is pending, take it now */
  		if( m6509.pending_irq )
  			m6509_take_irq();
  
  		op = RDOP();
  		(*m6509.insn[op])();
  
  		/* check if the I flag was just reset (interrupts enabled) */
  		if( m6509.after_cli )
  		{
  			log_cb(RETRO_LOG_DEBUG, LOGPRE "M6509#%d after_cli was >0", cpu_getactivecpu());
  			m6509.after_cli = 0;
  			if (m6509.irq_state != CLEAR_LINE)
  			{
  				log_cb(RETRO_LOG_DEBUG, LOGPRE ": irq line is asserted: set pending IRQ\n");
  				m6509.pending_irq = 1;
  			}
  			else
  			{
  				log_cb(RETRO_LOG_DEBUG, LOGPRE ": irq line is clear\n");
  			}
  		}
  		else
  		if( m6509.pending_irq )
  			m6509_take_irq();
  
  	} while (m6509_ICount > 0);
  
  	return cycles - m6509_ICount;
  }
  
  void m6509_set_irq_line(int irqline, int state)
  {
  	if (irqline == IRQ_LINE_NMI)
  	{
  		if (m6509.nmi_state == state) return;
  		m6509.nmi_state = state;
  		if( state != CLEAR_LINE )
  		{
  			log_cb(RETRO_LOG_DEBUG, LOGPRE  "M6509#%d set_nmi_line(ASSERT)\n", cpu_getactivecpu());
  			EAD = M6509_NMI_VEC;
  			EAWH = PBWH;
  			m6509_ICount -= 7;
  			PUSH(PCH);
  			PUSH(PCL);
  			PUSH(P & ~F_B);
  			P |= F_I;		/* knock out D and set I flag */
  			PCL = RDMEM(EAD);
  			PCH = RDMEM(EAD+1);
  			log_cb(RETRO_LOG_DEBUG, LOGPRE "M6509#%d takes NMI ($%04x)\n", cpu_getactivecpu(), PCD);
  			change_pc20(PCD);
  		}
  	}
  	else
  	{
  		if( irqline == M6509_SET_OVERFLOW )
  		{
  			if( m6509.so_state && !state )
  			{
  				log_cb(RETRO_LOG_DEBUG, LOGPRE  "M6509#%d set overflow\n", cpu_getactivecpu());
  				P|=F_V;
  			}
  			m6509.so_state=state;
  			return;
  		}
  		m6509.irq_state = state;
  		if( state != CLEAR_LINE )
  		{
  			log_cb(RETRO_LOG_DEBUG, LOGPRE  "M6509#%d set_irq_line(ASSERT)\n", cpu_getactivecpu());
  			m6509.pending_irq = 1;
  		}
  	}
  }
  
  void m6509_set_irq_callback(int (*callback)(int))
  {
  	m6509.irq_callback = callback;
  }
  
  /****************************************************************************
   * Return a formatted string for a register
   ****************************************************************************/
  const char *m6509_info(void *context, int regnum)
  {
  	static char buffer[16][47+1];
  	static int which = 0;
  	m6509_Regs *r = context;
  
  	which = (which+1) % 16;
  	buffer[which][0] = '\0';
  	if( !context )
  		r = &m6509;
  
  	switch( regnum )
  	{
  		case CPU_INFO_REG+M6509_PC: sprintf(buffer[which], "PC:%04X", r->pc.w.l); break;
  		case CPU_INFO_REG+M6509_S: sprintf(buffer[which], "S:%02X", r->sp.b.l); break;
  		case CPU_INFO_REG+M6509_P: sprintf(buffer[which], "P:%02X", r->p); break;
  		case CPU_INFO_REG+M6509_A: sprintf(buffer[which], "A:%02X", r->a); break;
  		case CPU_INFO_REG+M6509_X: sprintf(buffer[which], "X:%02X", r->x); break;
  		case CPU_INFO_REG+M6509_Y: sprintf(buffer[which], "Y:%02X", r->y); break;
  		case CPU_INFO_REG+M6509_PC_BANK: sprintf(buffer[which], "0:%01X", r->pc_bank.b.h2); break;
  		case CPU_INFO_REG+M6509_IND_BANK: sprintf(buffer[which], "1:%01X", r->ind_bank.b.h2); break;
  		case CPU_INFO_REG+M6509_EA: sprintf(buffer[which], "EA:%05X", r->ea.d); break;
  		case CPU_INFO_REG+M6509_ZP: sprintf(buffer[which], "ZP:%05X", r->zp.d); break;
  		case CPU_INFO_REG+M6509_NMI_STATE: sprintf(buffer[which], "NMI:%X", r->nmi_state); break;
  		case CPU_INFO_REG+M6509_IRQ_STATE: sprintf(buffer[which], "IRQ:%X", r->irq_state); break;
  		case CPU_INFO_REG+M6509_SO_STATE: sprintf(buffer[which], "SO:%X", r->so_state); break;
  		case CPU_INFO_FLAGS:
  			sprintf(buffer[which], "%c%c%c%c%c%c%c%c",
  				r->p & 0x80 ? 'N':'.',
  				r->p & 0x40 ? 'V':'.',
  				r->p & 0x20 ? 'R':'.',
  				r->p & 0x10 ? 'B':'.',
  				r->p & 0x08 ? 'D':'.',
  				r->p & 0x04 ? 'I':'.',
  				r->p & 0x02 ? 'Z':'.',
  				r->p & 0x01 ? 'C':'.');
  			break;
  		case CPU_INFO_NAME: return "M6509";
  		case CPU_INFO_FAMILY: return "MOS Technology 6509";
  		case CPU_INFO_VERSION: return "1.0beta";
  		case CPU_INFO_CREDITS:
  			return "Copyright (c) 1998 Juergen Buchmueller\n"
  				"Copyright (c) 2000 Peter Trauner\n"
  				"all rights reserved.";
  		case CPU_INFO_FILE: return __FILE__;
  		case CPU_INFO_REG_LAYOUT: return (const char*)m6509_reg_layout;
  		case CPU_INFO_WIN_LAYOUT: return (const char*)m6509_win_layout;
  	}
  	return buffer[which];
  }
  
  unsigned m6509_dasm(char *buffer, unsigned pc)
  {
  #ifdef MAME_DEBUG
  	return Dasm6509( buffer, pc );
  #else
  	sprintf( buffer, "$%02X", cpu_readop(pc) );
  	return 1;
  #endif
  }
  
  
  
  void m6509_init(void){ return; }
  
  