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

//------------------------------------------//
//              Dependencies                //
//------------------------------------------//

#ifndef _KALEID_H
#include <kaleid.h>
#endif

//------------------------------------------//
//             Start of header              //
//------------------------------------------//

#ifndef _KALKERN_BASE_H
#define _KALKERN_BASE_H

//------------------------------------------//
//           Elementary types               //
//------------------------------------------//

typedef struct sLock_t volatile     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;

//------------------------------------------//
//           Values for __kstate            //
//------------------------------------------//

//
// 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 NCPU
#define NCPU 4
#endif

#define GetCurCPU() 0

//
// Declare an (extern) CPU-local variable
//
#define __DECLARE_PER_CPU(_X, _Tp, _Qual)   \
    _Qual _Tp __ ## _X [NCPU];              \
    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 [NCPU] = { (_Tp) 0 }


//------------------------------------------//
//             Global constants             //
//------------------------------------------//

// 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 *);

//------------------------------------------//
//       Macros for manipulating said       //
//             global constants             //
//------------------------------------------//

#define SetPanicStr(str)                    \
    do {                                    \
        SetKernState(KSTATE_PANIC);         \
        _SetPanicStr(str);                  \
    } while (0)

#define SetKernState(x)                     \
    do {                                    \
        _SetKernState(x);                   \
    } while (0)

#define GetStdOut()         (GetCurProc() == NULL ? Get_StdOut() : NULL)
#define SetStdOut(tm)                       \
    do {                                    \
        if (GetCurProc() == NULL)           \
            _Set_StdOut(tm);                \
    } while (0);

#define GetStdDbg()         (GetCurProc() == NULL ? Get_StdDbg() : NULL)
#define SetStdDbg(tm)                       \
    do {                                    \
        if (GetCurProc() == NULL)           \
            _Set_StdDbg(tm);                \
    } while (0)

//------------------------------------------//
//               Other Macros               //
//------------------------------------------//

//
// 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)

//------------------------------------------//
//           Some base functions            //
//------------------------------------------//

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

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

static inline
void WriteByteOnPort(port_t port, port_t val)
{
    asm volatile ("out %0, %1" : : "dN" (port), "a" (val));
}

static inline
uchar ReadByteFromPort(port_t port)
{
    errno = ENOSYS;
    (void)port;
    return 0;
}

static inline
ushort ReadWordFromPort(port_t port)
{
    errno = ENOSYS;
    (void)port;
    return 0;
}

//------------------------------------------//
//              End of header               //
//------------------------------------------//

#endif