pc386.c

ucosii的实用程序

        *pscr++ = color;                                    /* Put video attribute in video RAM        */
    }
}
/*$PAGE*/
/*
*********************************************************************************************************
*                                       ELAPSED TIME INITIALIZATION
*
* Description : This function initialize the elapsed time module by determining how long the START and
*               STOP functions take to execute.  In other words, this function calibrates this module
*               to account for the processing time of the START and STOP functions.
*
* Arguments   : None.
*
* Returns     : None.
*********************************************************************************************************
*/
void PC_ElapsedInit(void)
{
    PC_ElapsedOverhead = 0;
    PC_ElapsedStart();
    PC_ElapsedOverhead = PC_ElapsedStop();
}
/*$PAGE*/
/*
*********************************************************************************************************
*                                         INITIALIZE PC'S TIMER #2
*
* Description : This function initialize the PC's Timer #2 to be used to measure the time between events.
*               Timer #2 will be running when the function returns.
*
* Arguments   : None.
*
* Returns     : None.
*********************************************************************************************************
*/
void PC_ElapsedStart(void)
{
    INT8U data;        


    data  = (INT8U)RTIn(0x61);                              /* Disable timer #2                         */
    data &= 0xFE;
    RTOut(0x61, data);
    RTOut(TICK_T0_8254_CWR,  TICK_T0_8254_CTR2_MODE0);      /* Program timer #2 for Mode 0              */
    RTOut(TICK_T0_8254_CTR2, 0xFF);
    RTOut(TICK_T0_8254_CTR2, 0xFF);
    data |= 0x01;                                          /* Start the timer                          */
    RTOut(0x61, data);
}
/*$PAGE*/
/*
*********************************************************************************************************
*                                 STOP THE PC'S TIMER #2 AND GET ELAPSED TIME
*
* Description : This function stops the PC's Timer #2, obtains the elapsed counts from when it was
*               started and converts the elapsed counts to micro-seconds.
*
* Arguments   : None.
*
* Returns     : The number of micro-seconds since the timer was last started.
*
* Notes       : - The returned time accounts for the processing time of the START and STOP functions.
*               - 54926 represents 54926S-16 or, 0.838097 which is used to convert timer counts to
*                 micro-seconds.  The clock source for the PC's timer #2 is 1.19318 MHz (or 0.838097 uS)
*********************************************************************************************************
*/
INT16U PC_ElapsedStop(void)
{
    INT8U  data;
    INT8U  low;
    INT8U  high;
    INT16U cnts;


    data  = RTIn(0x61);                                           /* Disable the timer                  */
    data &= 0xFE;
    RTOut(0x61, data);
    RTOut(TICK_T0_8254_CWR, TICK_T0_8254_CTR2_LATCH);             /* Latch the timer value              */
    low  = inportb(TICK_T0_8254_CTR2);
    high = inportb(TICK_T0_8254_CTR2);
    cnts = (INT16U)0xFFFF - (((INT16U)high << 8) + (INT16U)low); /* Compute time it took for operation */
    return ((INT16U)((INT32U)cnts * 54926L >> 16) - PC_ElapsedOverhead);
}
/*$PAGE*/
/*
*********************************************************************************************************
*                                       GET THE CURRENT DATE AND TIME
*
* Description: This function obtains the current date and time from the PC.
*
* Arguments  : s     is a pointer to where the ASCII string of the current date and time will be stored.
*                    You must allocate at least 19 bytes (includes the NUL) of storage in the return 
*                    string.
*
* Returns    : none
*********************************************************************************************************
*/
void PC_GetDateTime (char *s)
{
    SYSTEMTIME now;


    RTCMOSReadTime(&now);
    sprintf(s, "%02d-%02d-%02d  %02d:%02d:%02d",
               now.wMonth,
               now.wDay,
               now.wYear,
               now.wHour,
               now.wMinute,
               now.wSecond);
}
/*$PAGE*/
/*
*********************************************************************************************************
*                                        CHECK AND GET KEYBOARD KEY
*
* Description: This function checks to see if a key has been pressed at the keyboard and returns TRUE if
*              so.  Also, if a key is pressed, the key is read and copied where the argument is pointing
*              to.
*
* Arguments  : c     is a pointer to where the read key will be stored.
*
* Returns    : TRUE  if a key was pressed
*              FALSE otherwise
*********************************************************************************************************
*/
BOOLEAN PC_GetKey (INT16S *c)
{
    if (kbhit()) {                                         /* See if a key has been pressed            */
        *c = getch();                                      /* Get key pressed                          */
        return (TRUE);
    } else {
        *c = 0x00;                                         /* No key pressed                           */
        return (FALSE);
    }
}
/*$PAGE*/
/*
*********************************************************************************************************
*                                      SET THE PC'S TICK FREQUENCY
*
* Description: This function is called to change the tick rate of a PC.
*
* Arguments  : freq      is the desired frequency of the ticker (in Hz)
*
* Returns    : none
*
* Notes      : 1) The magic number 2386360 is actually twice the input frequency of the 8254 chip which
*                 is always 1.193180 MHz.
*              2) The equation computes the counts needed to load into the 8254.  The strange equation
*                 is actually used to round the number using integer arithmetic.  This is equivalent to
*                 the floating point equation:
*
*                             1193180.0 Hz
*                     count = ------------ + 0.5
*                                 freq
*********************************************************************************************************
*/
void PC_SetTickRate (INT16U freq)
{
    INT16U count;

    if (freq == 18) {	/* See if we need to restore the DOS frequency        */
        count = 0;
    } else if (freq > 0) {
//                                                /* Compute 8254 counts for desired frequency and ...  */
//                                                /* ... round to nearest count                         */
        count = ((INT32U)2386360/freq + 1)/2 ;
	} else {
	count = 0;
    }
	RTOut(TICK_T0_8254_CWR,  TICK_T0_8254_CTR0_MODE3);/* Load the 8254 with desired frequency          */  
    RTOut(TICK_T0_8254_CTR0, (INT8U)(count & 0xFF));      /* Low  byte                                     */
    RTOut(TICK_T0_8254_CTR0, (INT8U)((count/256) & 0xFF)); /* High byte                                     */
}