/* kernel.h */

/* General type declarations used throughout the kernel */

typedef unsigned char   byte;
typedef unsigned char   uint8;
typedef int             int32;
typedef short           int16;
typedef unsigned int    uint32;
typedef unsigned short  uint16;
typedef unsigned long long uint64;

/* Xinu-specific types */

typedef int32   sid32;          /* Semaphore ID                         */
typedef int16   qid16;          /* Queue ID                             */
typedef int32   pid32;          /* Process ID                           */
typedef int32   did32;          /* Device ID                            */
typedef int16   pri16;          /* Process priority                     */
#define MAXPRIO 0x7fff          /* Maximum possible priority            */
typedef uint32  umsg32;         /* Message passed among processes       */
typedef int32   bpid32;         /* Buffer pool ID                       */
typedef byte    bool8;          /* Boolean type                         */
typedef uint32  intmask;        /* Saved interrupt mask                 */
typedef int32   ibid32;         /* Index block ID (used in file system) */
typedef int32   dbid32;         /* Data block ID (used in file system)  */
typedef int32   uid32;          /* ID for UDP table descriptor          */

/* Function declaration return types */

typedef int32   syscall;        /* System call declaration              */
typedef int32   devcall;        /* Device call declaration              */
typedef int32   shellcmd;       /* Shell command declaration            */
typedef int32   process;        /* Top-level function of a process      */
typedef void    interrupt;      /* Interrupt function                   */
typedef int32   status;         /* Returned status value (OK/SYSERR)    */

#define local   static          /* Local procedure or variable declar.  */

/* Boolean constants */

#define FALSE   0               /* Boolean False                        */
#define TRUE    1               /* Boolean True                         */

/* Null pointer, character, and string definintions */

#define NULL    0               /* Null pointer for linked lists        */
#define NULLCH  '\0'            /* Null character                       */
#define NULLSTR ""              /* Null string                          */

/* Universal return constants */

#define OK      ( 1)            /* Normal system call return            */
#define SYSERR  (-1)            /* System call failed                   */
#define EOF     (-2)            /* End-of-file (usually from read)      */
#define TIMEOUT (-3)            /* System call timed out                */

extern  qid16   readylist;      /* Global ID for list of ready processes*/

#define MINSTK  400             /* Minimum stack size in bytes          */

#define CONTEXT 64              /* Bytes in a function call context on  */
                                /* The run-time stack                   */
#define QUANTUM 2               /* Time slice in milliseconds           */

/* Size of the stack for the null process */

#define NULLSTK         8192    /* Stack  size for null process         */

/* Prototypes of I/O functions used throughout the kernel */

syscall kprintf(char *fmt, ...);
syscall kputc(byte);
syscall kgetc(void);