?? pc.c
字號:
INT16U offset;
offset = (INT16U)y * DISP_MAX_X * 2 + (INT16U)x * 2; /* Calculate position of 1st character */
pscr = MK_FP(DISP_BASE, offset);
while (*s) {
*pscr++ = *s++; /* Put character in video RAM */
*pscr++ = color; /* Put video attribute in video RAM */
}
}
/*$PAGE*/
/*
*********************************************************************************************************
* RETURN TO DOS
*
* Description : This functions returns control back to DOS by doing a 'long jump' back to the saved
* location stored in 'PC_JumpBuf'. The saved location was established by the function
* 'PC_DOSSaveReturn()'. After execution of the long jump, execution will resume at the
* line following the 'set jump' back in 'PC_DOSSaveReturn()'. Setting the flag
* 'PC_ExitFlag' to TRUE ensures that the 'if' statement in 'PC_DOSSaveReturn()' executes.
*
* Arguments : None
*
* Returns : None
*********************************************************************************************************
*/
void PC_DOSReturn (void) KCREENTRANT
{
PC_ExitFlag = TRUE; /* Indicate we are returning to DOS */
longjmp(PC_JumpBuf, 1); /* Jump back to saved environment */
}
/*$PAGE*/
/*
*********************************************************************************************************
* SAVE DOS RETURN LOCATION
*
* Description : This function saves the location of where we are in DOS so that it can be recovered.
* This allows us to abort multitasking under uC/OS-II and return back to DOS as if we had
* never left. When this function is called by 'main()', it sets 'PC_ExitFlag' to FALSE
* so that we don't take the 'if' branch. Instead, the CPU registers are saved in the
* long jump buffer 'PC_JumpBuf' and we simply return to the caller. If a 'long jump' is
* performed using the jump buffer then, execution would resume at the 'if' statement and
* this time, if 'PC_ExitFlag' is set to TRUE then we would execute the 'if' statements and
* restore the DOS environment.
*
* Arguments : None
*
* Returns : None
*********************************************************************************************************
*/
void PC_DOSSaveReturn (void) KCREENTRANT
{
#if OS_CRITICAL_METHOD == 3
OS_CPU_SR cpu_sr;
#endif
PC_ExitFlag = FALSE; /* Indicate that we are not exiting yet! */
OSTickDOSCtr = 1; /* Initialize the DOS tick counter */
PC_TickISR = PC_VectGet(VECT_TICK); /* Get MS-DOS's tick vector */
OS_ENTER_CRITICAL();
PC_VectSet(VECT_DOS_CHAIN, PC_TickISR); /* Store MS-DOS's tick to chain */
OS_EXIT_CRITICAL();
setjmp(PC_JumpBuf); /* Capture where we are in DOS */
if (PC_ExitFlag == TRUE) { /* See if we are exiting back to DOS */
OS_ENTER_CRITICAL();
PC_SetTickRate(18); /* Restore tick rate to 18.2 Hz */
PC_VectSet(VECT_TICK, PC_TickISR); /* Restore DOS's tick vector */
OS_EXIT_CRITICAL();
PC_DispClrScr(DISP_FGND_WHITE + DISP_BGND_BLACK); /* Clear the display */
exit(0); /* Return to DOS */
}
}
/*$PAGE*/
/*
*********************************************************************************************************
* ELAPSED TIME INITIALIZATION
*
* Description : This function initialize the elapsed time module by determining how long the START and
* STOP functions take to execute. In other words, this function calibrates this module
* to account for the processing time of the START and STOP functions.
*
* Arguments : None.
*
* Returns : None.
*********************************************************************************************************
*/
void PC_ElapsedInit(void) KCREENTRANT
{
PC_ElapsedOverhead = 0;
PC_ElapsedStart();
PC_ElapsedOverhead = PC_ElapsedStop();
}
/*$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.
*********************************************************************************************************
*/
data INT16U TickCount;
void UserTickTimer(void) KCREENTRANT
{
TickCount++;
}
void PC_ElapsedStart(void) KCREENTRANT
{
//
// INT8U vdata;
//
//
// vdata = (INT8U)inp(0x61); /* Disable timer #2 */
// vdata &= 0xFE;
// outp(0x61, vdata);
// outp(TICK_T0_8254_CWR, TICK_T0_8254_CTR2_MODE0); /* Program timer #2 for Mode 0 */
// outp(TICK_T0_8254_CTR2, 0xFF);
// outp(TICK_T0_8254_CTR2, 0xFF);
// vdata |= 0x01; /* Start the timer */
// outp(0x61, vdata);
TickCount=0;
}
/*$PAGE*/
/*
*********************************************************************************************************
* STOP THE PC'S TIMER #2 AND GET ELAPSED TIME
*
* Description : This function stops the PC's Timer #2, obtains the elapsed counts from when it was
* started and converts the elapsed counts to micro-seconds.
*
* Arguments : None.
*
* Returns : The number of micro-seconds since the timer was last started.
*
* Notes : - The returned time accounts for the processing time of the START and STOP functions.
* - 54926 represents 54926S-16 or, 0.838097 which is used to convert timer counts to
* micro-seconds. The clock source for the PC's timer #2 is 1.19318 MHz (or 0.838097 uS)
*********************************************************************************************************
*/
INT16U PC_ElapsedStop(void) KCREENTRANT
{
return TickCount;
// INT8U vdata;
// INT8U low;
// INT8U high;
// INT16U cnts;
//
//
// vdata = inp(0x61); /* Disable the timer */
// vdata &= 0xFE;
// outp(0x61, vdata);
// outp(TICK_T0_8254_CWR, TICK_T0_8254_CTR2_LATCH); /* Latch the timer value */
// low = inp(TICK_T0_8254_CTR2);
// high = inp(TICK_T0_8254_CTR2);
// cnts = (INT16U)0xFFFF - (((INT16U)high << 8) + (INT16U)low); /* Compute time it took for operation */
// return ((INT16U)((ULONG)cnts * 54926L >> 16) - PC_ElapsedOverhead);
}
/*$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) KCREENTRANT
{
struct time now;
struct date today;
gettime(&now);
getdate(&today);
sprintf(s, "%02bd-%02bd-%02bd %02bd:%02bd:%02bd",
today.da_mon,
today.da_day,
today.da_year,
now.ti_hour,
now.ti_min,
now.ti_sec);
}
/*$PAGE*/
/*
*********************************************************************************************************
* CHECK AND GET KEYBOARD KEY
*
* Description: This function checks to see if a key has been pressed at the keyboard and returns TRUE if
* so. Also, if a key is pressed, the key is read and copied where the argument is pointing
* to.
*
* Arguments : c is a pointer to where the read key will be stored.
*
* Returns : TRUE if a key was pressed
* FALSE otherwise
*********************************************************************************************************
*/
BOOLEAN PC_GetKey (INT16S *c) KCREENTRANT
{
if (kbhit()) { /* See if a key has been pressed */
*c = getch(); /* Get key pressed */
return (TRUE);
} else {
*c = 0x00; /* No key pressed */
return (FALSE);
}
}
/*$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) KCREENTRANT
{
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 = (INT16U)(((INT32U)2386360L / freq + 1) >> 1);
} else {
count = 0;
}
outp(TICK_T0_8254_CWR, TICK_T0_8254_CTR0_MODE3); /* Load the 8254 with desired frequency */
outp(TICK_T0_8254_CTR0, count & 0xFF); /* Low byte */
outp(TICK_T0_8254_CTR0, (count >> 8) & 0xFF); /* High byte */
}
/*$PAGE*/
/*
*********************************************************************************************************
* OBTAIN INTERRUPT VECTOR
*
* Description: This function reads the pointer stored at the specified vector.
*
* Arguments : vect is the desired interrupt vector number, a number between 0 and 255.
*
* Returns : none
*********************************************************************************************************
*/
void *PC_VectGet (INT8U vect) KCREENTRANT
{
return (getvect(vect));
}
/*
*********************************************************************************************************
* INSTALL INTERRUPT VECTOR
*
* Description: This function sets an interrupt vector in the interrupt vector table.
*
* Arguments : vect is the desired interrupt vector number, a number between 0 and 255.
* isr is a pointer to a function to execute when the interrupt or exception occurs.
*
* Returns : none
*********************************************************************************************************
*/
void PC_VectSet (INT8U vect, void (*isr)(void)) KCREENTRANT
{
setvect(vect, (void interrupt (*)(void))isr);
}
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