local ffi = require("ffi")

ffi.cdef[[

/* =============================================================================
 *  libz80 - Z80 emulation library
 * =============================================================================
 *
 * (C) Gabriel Gambetta (gabriel.gambetta@gmail.com) 2000 - 2012
 *
 * Version 2.1.0
 *
 * -----------------------------------------------------------------------------
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

/* modified from libz80.h for minetest by J. Aldo G. de F. Junior 2014 */

typedef unsigned short ushort;
typedef unsigned char byte;

typedef byte (*Z80DataIn)   (int param, ushort address);
typedef void (*Z80DataOut)  (int param, ushort address, byte data);

typedef union
{
    struct
    {
        ushort AF, BC, DE, HL, IX, IY, SP;
    } wr;

    struct
    {
        byte F, A, C, B, E, D, L, H, IXl, IXh, IYl, IYh;
    } br;
} Z80Regs;

typedef enum
{
    F_C  =   1,
    F_N  =   2,
    F_PV =   4,
    F_3  =   8,
    F_H  =  16,
    F_5  =  32,
    F_Z  =  64,
    F_S  = 128
} Z80Flags;

typedef struct
{
    Z80Regs     R1;
    Z80Regs     R2;
    ushort      PC;
    byte        R;
    byte        I;
    byte        IFF1;
    byte        IFF2;
    byte        IM;
    Z80DataIn   memRead;
    Z80DataOut  memWrite;
    int         memParam;
    Z80DataIn   ioRead;
    Z80DataOut  ioWrite;
    int         ioParam;
    byte        halted;
    unsigned    tstates;
    byte        nmi_req;
    byte        int_req;
    byte        defer_int;
    byte        int_vector;
    byte        exec_int_vector;
} Z80Context;

/* Low level library routines */

void Z80Execute (Z80Context* ctx);
unsigned Z80ExecuteTStates(Z80Context* ctx, unsigned tstates);
void Z80Debug (Z80Context* ctx, char* dump, char* decode);
void Z80RESET (Z80Context* ctx);
void Z80INT (Z80Context* ctx, byte value);
void Z80NMI (Z80Context* ctx);

/* End of low level routines */

typedef enum
{
    IO_MemRead = 1,
    IO_MemWrite = 2,
    IO_BusRead = 4,
    IO_BusWrite = 8
} IOKind;

typedef struct
{
    IOKind      ikind;
    ushort      iaddress;
    byte        idata;
} IOContext;

typedef struct
{
    byte        MemSpace[65536];
    byte        IOSpace[65536];
    IOContext   IOInfo;
    Z80Context  Context;
} Z80Machine;

Z80Machine machine;

byte IOZ80DataIn(int param, ushort address)
{
    machine.IOInfo.ikind = IO_BusRead;
    machine.IOInfo.iaddress = address;
    machine.IOInfo.idata = machine.IOSpace[address];
    return machine.IOInfo.idata;
};

void IOZ80DataOut(int param, ushort address, byte data)
{
    machine.IOInfo.ikind = IO_BusWrite;
    machine.IOInfo.iaddress = address;
    machine.IOInfo.idata = data;
    machine.IOSpace[address] = data;
};

byte MemZ80DataIn(int param, ushort address)
{
    machine.IOInfo.ikind = IO_MemRead;
    machine.IOInfo.iaddress = address;
    machine.IOInfo.idata = 0;
    return machine.MemSpace[address];
};

void MemZ80DataOut(int param, ushort address, byte data)
{
    machine.IOInfo.ikind = IO_MemWrite;
    machine.IOInfo.iaddress = address;
    machine.IOInfo.idata = data;
    machine.MemSpace[address] = data;
};

/* Use those functions to run the emulator */

void Z80MachineStart()
{
    machine.Z80Context.memRead = &MemZ80DataIn;
    machine.Z80Context.memWrite = &MemZ80DataOut;
    machine.Z80Context.ioRead = &IOZ80DataIn;
    machine.Z80Context.ioWrite = &MemZ80DataOut;
    Z80RESET(&machine.Z80Context);
};

void Z80MachineCycle()
{
    Z80Execute(&machine.Z80Context);
};

void Z80GenerateInterrupt(byte value)
{
    Z80Int(&machine.Z80Context, value);
};

void Z80GenerateNMI()
{
    Z80NMI(&machine.Z80Context)
};

]]

local libz80 = ffi.load('z80');