//----------------------------------------------------------------------------//
//                           GNU GPL OS/K                                     //
//                                                                            //
//  Authors:    spectral`                                                     //
//              NeoX                                                          //
//                                                                            //
//  Desc:       Kaleid Kernel base types and functionalities                  //
//----------------------------------------------------------------------------//

#ifndef _KALBASE_H
#include <kalbase.h>
#endif

//------------------------------------------//

#ifndef _KALKERN_BASE_H
#define _KALKERN_BASE_H

//------------------------------------------//

typedef struct sLock_t              Lock_t;
typedef struct sThread_t            Thread_t;
typedef struct sProcess_t           Process_t;
typedef struct sTerminal_t          Terminal_t;
typedef struct sListHead_t          ListHead_t;
typedef struct sListNode_t          ListNode_t;

//------------------------------------------//

/* XXX */

//
// Current state of the kernel
//
typedef enum {
    // The kernel is booting
    KSTATE_INIT,

    // The kernel is not running a process
    KSTATE_KERNEL,

    // A process is running in kernel mode
    KSTATE_PROCESS,

    // The kernel is panicking
    KSTATE_PANIC,

} KernelState_t;

//------------------------------------------//
//            Multiprocessor misc.          //
//------------------------------------------//

#ifndef INITOK
#define INITOK ((unsigned int)0xCAFEBABE)
#endif

#ifndef NCPUS
#define NCPUS 4
#endif

#define GetCurCPU() 0

//
// Declare an (extern) CPU-local variable
//
#define __DECLARE_PER_CPU(_X, _Tp, _Qual)   \
    _Qual _Tp __ ## _X [NCPUS];             \
    static inline _Tp Get ## _X (void)      \
        { return __ ## _X [GetCurCPU()]; }  \
    static inline void _Set ## _X (_Tp _Y)  \
        { (__ ## _X [GetCurCPU()] = _Y); }

#define DECLARE_PER_CPU(_X, _Tp)            \
      __DECLARE_PER_CPU(_X, _Tp, extern)

#define LOCAL_DEC_PER_CPU(_X, _Tp)          \
      __DECLARE_PER_CPU(_X, _Tp, static)

//
// Actually creates a CPU-local variable
//
#define CREATE_PER_CPU(_X, _Tp)             \
    _Tp __ ## _X [NCPUS] = { (_Tp) 0 }


//------------------------------------------//

// XXX
DECLARE_PER_CPU(PanicStr,       const char *);

DECLARE_PER_CPU(KernState,      KernelState_t);

DECLARE_PER_CPU(_StdOut,        Terminal_t *);
DECLARE_PER_CPU(_StdDbg,        Terminal_t *);

DECLARE_PER_CPU(CurProc,        Process_t *);
DECLARE_PER_CPU(CurThread,      Thread_t *);

DECLARE_PER_CPU(ReSchedFlag,    bool);
DECLARE_PER_CPU(PreemptCount,   ulong);

//------------------------------------------//

#define SetKernState(x)     _SetKernState(x);

//
// StdOut/StdDbg manipulation
//
#define GetStdOut()         (GetCurProc() == NULL ? Get_StdOut() : GetCurProc()->stdOut)
#define GetStdDbg()         (GetCurProc() == NULL ? Get_StdDbg() : GetCurProc()->stdDbg)
#define SetStdOut(tm)       do { if (GetCurProc() == NULL) _Set_StdOut(tm); \
                                 else GetCurProc()->stdOut = (tm); } while (0)
#define SetStdDbg(tm)       do { if (GetCurProc() == NULL) _Set_StdDbg(tm); \
                                 else GetCurProc()->stdDbg = (tm); } while (0)
//
// Re-scheduling and preemption
// XXX XXX XXX atomic operations
//
#define SetReSchedFlag(x)    _SetReSchedFlag(x)
#define DisablePreemption()  _SetPreemptCount(GetPreemptCount()+1)
#define EnablePreemption()   do { KalAssert(GetPreemptCount() > 0); \
                                 _SetPreemptCount(GetPreemptCount()-1); } while(0)

//------------------------------------------//

//
// Value of the preemption count indicating that preemption is activated
//
#define PREEMPT_ON           0

//
// Size of a tabulation in spaces
// Default: 4 spaces/tab
//
#define KTABSIZE 4

//
// Disable IRQs
//
#define DisableIRQs() asm volatile ("cli")

//
// Enable IRQs
//
#define EnableIRQs() asm volatile ("sti")

//
// Pause CPU until next interuption
// !!! Enables IRQs !!!
//
#define PauseCPU() asm volatile("sti\n\thlt")

//
// Halt the CPU indefinitely
//
#define HaltCPU() do { asm volatile ("hlt"); } while (1)

//------------------------------------------//

//
// A process
//
typedef struct sProcess_t {

    // Identifier
    int         pid;

    // Current priority class
    int         prioClass;

    // Default priority class (without boosts)
    int         defPrioClass;

    // Current priority level
    int         prioLevel;

    // Default priority level
    int         defPrioLevel;

    // Current state
    int         procState;

    // Remaining time running
    ulong       timeSlice;

    // Default time-slice
    ulong       defTimeSlice;

    // Scheduler internals
    ListNode_t *schedNode;

    // Standard output/debug
    Terminal_t *stdOut, *stdDbg;

} Process_t;

//------------------------------------------//

noreturn void StartPanic(const char *);
noreturn void CrashSystem(void);

//------------------------------------------//
//            Useful I/O inlines            //
//------------------------------------------//


static inline
void WriteByteOnPort(port_t port, port_t val)
{
    KalAssert(FALSE && ENOSYS);
    (void)port;
    (void)val;
}

static inline
uchar ReadByteFromPort(port_t port)
{
    KalAssert(FALSE && ENOSYS);
    (void)port;
    return 0;
}

static inline
ushort ReadWordFromPort(port_t port)
{
    KalAssert(FALSE && ENOSYS);
    (void)port;
    return 0;
}

//------------------------------------------//

#endif