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cia.c
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C/C++ Source or Header
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1992-05-06
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4KB
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142 lines
/************************************************************************
********** **********
********** C I A I N T E R R U P T **********
********** ------------------------- **********
********** **********
********** Copyright (C) 1988 Sassenrath Research **********
********** All Rights Reserved. **********
********** **********
********** Example from the "Guru's Guide, Meditation #1" **********
********** **********
*************************************************************************
** **
** - NOTICE - **
** **
** The "Guru's Guide, Meditation #1" contains detailed information **
** about Amiga interrupts as well as a complete discussion of this **
** and other examples. Meditation #1 and all of its examples were **
** written by Carl Sassenrath, the architect of Amiga's multitasking **
** operating system. Copies of the "Guru's Guide" may be obtained **
** from: **
** GURU'S GUIDE, P.O. BOX 1510, UKIAH, CA 95482 **
** **
** Please include a check for $14.95, plus $1.50 shipping ($4.00 if **
** outside North America). CA residents add 6% sales tax. **
** **
** This example may be used for any purposes, commercial, personal, **
** public, and private, so long as ALL of the above text, copyright, **
** mailing address, and this notice are retained in their entirety. **
** **
** THIS EXAMPLE IS PROVIDED WITHOUT WARRANTY OF ANY KIND. **
** **
************************************************************************/
/*
** COMPILATION NOTE:
**
** Compiled under MANX AZTEC C 3.6A. Use the +L compiler option
** and the "c32" library. Link with intrsup.o.
*/
#include <exec/exec.h>
#include <hardware/intbits.h>
#include <hardware/cia.h>
struct Task *ATask = NULL;
struct Interrupt *Intr = NULL;
APTR Cia = NULL;
long ASignal = -1;
long Counter = 10;
/* Interrupt Processing Code */
VOID IntrProc()
{
int_start();
/* Clear timer-A interrupt */
SetICR(Cia, CIAICRF_TA);
if (--Counter <= 0)
{
/* Disable timer interrupt */
AbleICR(Cia, CIAICRF_TA);
Signal(ATask,1 << ASignal);
}
int_end();
}
main()
{
MainInit();
if (AddICRVector(Cia,CIAICRB_TA,Intr) != 0)
{
puts("CIA-B Timer-A in use.");
MainExit(300);
}
/* At this point, Timer intr is linked */
/* and enabled, so it may have happened */
/* already! That's why we need this: */
ciab.ciacra &= ~CIACRAF_START; /* stop timer */
SetICR(Cia,CIAICRF_TA); /* clear intr */
SetSignal(0, 1 << ASignal); /* clear signal */
/* Set timer counter latch */
ciab.ciatalo = 0;
ciab.ciatahi = 0xff;
/* Start the timer */
ciab.ciacra |= CIACRAF_START;
while (Counter > 0)
printf("%d %2x%02x\n", Counter, ciab.ciatahi, ciab.ciatalo);
Wait(1 << ASignal); /* Sync-up */
ciab.ciacra &= ~CIACRAF_START; /* stop timer */
RemICRVector(Cia,CIAICRB_TA,Intr);
MainExit(0);
}
MainInit()
{
extern APTR OpenResource();
extern struct Interrupt *MakeIntr();
extern struct Task *FindTask();
extern int Enable_Abort;
Enable_Abort = 0; /* prevent a CTRL-C */
Cia = OpenResource("ciab.resource", 0);
if (Cia == NULL) MainExit(201);
Intr = MakeIntr("cia.example",0,&IntrProc,0);
if (Intr == NULL) MainExit(202);
ASignal = AllocSignal(-1);
if (ASignal == -1) MainExit(203);
ATask = FindTask(NULL);
}
MainExit(error)
int error;
{
FreeIntr(Intr);
if (ASignal != -1) FreeSignal(ASignal);
exit(error);
}