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/* Project:     OSLib
 * Description: The OS Construction Kit
 * Date:                1.6.2000
 * Idea by:             Luca Abeni & Gerardo Lamastra
 *
 * OSLib is an SO project aimed at developing a common, easy-to-use
 * low-level infrastructure for developing OS kernels and Embedded
 * Applications; it partially derives from the HARTIK project but it
 * currently is independently developed.
 *
 * OSLib is distributed under GPL License, and some of its code has
 * been derived from the Linux kernel source; also some important
 * ideas come from studying the DJGPP go32 extender.
 *
 * We acknowledge the Linux Community, Free Software Foundation,
 * D.J. Delorie and all the other developers who believe in the
 * freedom of software and ideas.
 *
 * For legalese, check out the included GPL license.
 */

/*      Time management code: ll_getttime()     */

#include <ll/i386/pit.h>
#include <ll/i386/stdlib.h>
#include <ll/i386/error.h>
#include <ll/i386/mem.h>
#include <ll/sys/ll/ll-data.h>
#include <ll/sys/ll/ll-func.h>
#include <ll/sys/ll/time.h>

/* These are for the EXECT and TICK modes */
extern DWORD ticksize;          /* From init.c  */
extern struct timespec actTime; /* From event.c */
extern WORD pit_time_const;     /* From init.c  */
extern DWORD timermode;         /* From init.c  */

/* These two are for the NEW algorithm */
extern WORD lastTime;           /* From event.c */
extern struct pitspec globalCounter;    /* From event.c */
extern BYTE frc;


extern int activeEvent;

FILE(Time);

TIME ll_gettime(int mode, struct timespec *tsres)
{
    DWORD res, tc;
    BYTE isr;
    struct timespec tmp;

    if (activeEvent) {
      if (tsres != NULL) {
        PITSPEC2TIMESPEC(&globalCounter, tsres);
        return TIMESPEC2USEC(tsres);
      } else {
        PITSPEC2TIMESPEC(&globalCounter, &tmp);
        return TIMESPEC2USEC(&tmp);
      }
    }

    if (mode == TIME_PTICK) {
        if (timermode != LL_PERIODIC) {
            return 0;
        }
        res = TIMESPEC2USEC(&actTime);
        if (tsres != NULL) {
            memcpy(tsres, &actTime, sizeof(struct timespec));
        }
        return res;
    }

    if (mode == TIME_EXACT) {
        WORD tmp;

        tmp = pit_read(frc);
        ADDPITSPEC((WORD) (lastTime - tmp), &globalCounter);
        lastTime = tmp;
        if (tsres != NULL) {
            PITSPEC2TIMESPEC(&globalCounter, tsres);
        }
        return (PITSPEC2USEC(&globalCounter));
    }

    if (mode == TIME_NEW) {
        if (timermode == LL_PERIODIC) {
            memcpy(&tmp, &actTime, sizeof(struct timespec));
            /* How much time has elapsed
             * from the last Tick Boundary?
             */
            tc = pit_read(0);
            if (tc > pit_time_const) {
                error("LL Time Panic!!!\n");
                ll_abort(1);
            }
            res = pit_time_const - tc;
            res *= ticksize;
            res /= pit_time_const;

            /* Detect tick boundary and adjust the time... */
            outp(0x20, 0x0A);
            isr = inp(0x20);
            if ((isr & 1) && res < ((8 * ticksize) / 10)) {
                /*
                   res += ticksize;
                   ADDNANO2TIMESPEC(ticksize * 1000, &tmp);
                 */
                res = ticksize;
            }

            /* Sum the Tick time... */
            ADDNANO2TIMESPEC(res * 1000, &tmp);
            res += TIMESPEC2USEC(&actTime);

            if (tsres != NULL) {
                memcpy(tsres, &tmp, sizeof(struct timespec));
            }
            return res;
        } else {
            return 0;
        }
    }
    return 0;
}