/*
 * COPYRIGHT:       GPL - See COPYING in the top level directory
 * PROJECT:         ReactOS Virtual DOS Machine
 * FILE:            emulator.h
 * PURPOSE:         Minimal x86 machine emulator for the VDM
 * PROGRAMMERS:     Aleksandar Andrejevic <theflash AT sdf DOT lonestar DOT org>
 */

#ifndef _EMULATOR_H_
#define _EMULATOR_H_

/* INCLUDES *******************************************************************/

#include "ntvdm.h"
#include <fast486.h>

/* DEFINES ********************************************************************/

/* FLAGS */
#define EMULATOR_FLAG_CF (1 << 0)
#define EMULATOR_FLAG_PF (1 << 2)
#define EMULATOR_FLAG_AF (1 << 4)
#define EMULATOR_FLAG_ZF (1 << 6)
#define EMULATOR_FLAG_SF (1 << 7)
#define EMULATOR_FLAG_TF (1 << 8)
#define EMULATOR_FLAG_IF (1 << 9)
#define EMULATOR_FLAG_DF (1 << 10)
#define EMULATOR_FLAG_OF (1 << 11)
#define EMULATOR_FLAG_NT (1 << 14)
#define EMULATOR_FLAG_RF (1 << 16)
#define EMULATOR_FLAG_VM (1 << 17)
#define EMULATOR_FLAG_AC (1 << 18)
#define EMULATOR_FLAG_VIF (1 << 19)
#define EMULATOR_FLAG_VIP (1 << 20)
#define EMULATOR_FLAG_ID (1 << 21)

#define STACK_VAR_B     0
#define STACK_VAR_A     1
#define STACK_COUNTER   2
#define STACK_INT_NUM   3
#define STACK_IP        4
#define STACK_CS        5
#define STACK_FLAGS     6


/* Basic Memory Management */
#define MEM_ALIGN_UP(ptr, align)    MEM_ALIGN_DOWN((ULONG_PTR)(ptr) + (align) - 1l, (align))
#define MEM_ALIGN_DOWN(ptr, align)  (PVOID)((ULONG_PTR)(ptr) & ~((align) - 1l))

#define TO_LINEAR(seg, off) (((seg) << 4) + (off))
#define MAX_SEGMENT 0xFFFF
#define MAX_OFFSET  0xFFFF
#define MAX_ADDRESS 0x1000000 // 16 MB of RAM

#define FAR_POINTER(x)  \
    (PVOID)((ULONG_PTR)BaseAddress + TO_LINEAR(HIWORD(x), LOWORD(x)))

#define SEG_OFF_TO_PTR(seg, off)    \
    (PVOID)((ULONG_PTR)BaseAddress + TO_LINEAR((seg), (off)))

#define REAL_TO_PHYS(ptr)   (PVOID)((ULONG_PTR)(ptr) + (ULONG_PTR)BaseAddress)
#define PHYS_TO_REAL(ptr)   (PVOID)((ULONG_PTR)(ptr) - (ULONG_PTR)BaseAddress)


/* BCD-Binary conversion */
#define BINARY_TO_BCD(x) ((((x) / 1000) << 12) + (((x) / 100) << 8) + (((x) / 10) << 4) + ((x) % 10))
#define BCD_TO_BINARY(x) (((x) >> 12) * 1000 + ((x) >> 8) * 100 + ((x) >> 4) * 10 + ((x) & 0x0F))


/* System I/O ports */
#define CONTROL_SYSTEM_PORT61H  0x61


enum
{
    EMULATOR_EXCEPTION_DIVISION_BY_ZERO,
    EMULATOR_EXCEPTION_DEBUG,
    EMULATOR_EXCEPTION_NMI,
    EMULATOR_EXCEPTION_BREAKPOINT,
    EMULATOR_EXCEPTION_OVERFLOW,
    EMULATOR_EXCEPTION_BOUND,
    EMULATOR_EXCEPTION_INVALID_OPCODE,
    EMULATOR_EXCEPTION_NO_FPU,
    EMULATOR_EXCEPTION_DOUBLE_FAULT,
    EMULATOR_EXCEPTION_FPU_SEGMENT,
    EMULATOR_EXCEPTION_INVALID_TSS,
    EMULATOR_EXCEPTION_NO_SEGMENT,
    EMULATOR_EXCEPTION_STACK_SEGMENT,
    EMULATOR_EXCEPTION_GPF,
    EMULATOR_EXCEPTION_PAGE_FAULT
};

extern FAST486_STATE EmulatorContext;
extern LPVOID  BaseAddress;
extern BOOLEAN VdmRunning;

/* FUNCTIONS ******************************************************************/

VOID WINAPI EmulatorReadMemory
(
    PFAST486_STATE State,
    ULONG Address,
    PVOID Buffer,
    ULONG Size
);

VOID WINAPI EmulatorWriteMemory
(
    PFAST486_STATE State,
    ULONG Address,
    PVOID Buffer,
    ULONG Size
);

UCHAR WINAPI EmulatorIntAcknowledge
(
    PFAST486_STATE State
);

VOID EmulatorException(BYTE ExceptionNumber, LPWORD Stack);

VOID EmulatorExecute(WORD Segment, WORD Offset);
VOID EmulatorStep(VOID);
VOID EmulatorSimulate(VOID);
VOID EmulatorUnsimulate(VOID);
VOID EmulatorTerminate(VOID);

VOID EmulatorInterrupt(BYTE Number);
VOID EmulatorInterruptSignal(VOID);
VOID EmulatorSetA20(BOOLEAN Enabled);

BOOLEAN EmulatorInitialize(HANDLE ConsoleInput, HANDLE ConsoleOutput);
VOID EmulatorCleanup(VOID);

#endif // _EMULATOR_H_

/* EOF */