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intrsup.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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150 lines
/************************************************************************
********** **********
********** I N T E R R U P T S U P P O R 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.
** This file is linked with most of the other interrupt examples.
*/
#include <exec/interrupts.h>
#include <exec/memory.h>
#include <hardware/custom.h>
#include <hardware/intbits.h>
/*
** Interrupt Controller Functions
*/
EnableIntr(intrNum)
int intrNum;
{
custom.intena = INTF_SETCLR | (1 << intrNum);
}
DisableIntr(intrNum)
int intrNum;
{
custom.intena = (1 << intrNum);
}
RequestIntr(intrNum)
int intrNum;
{
custom.intreq = INTF_SETCLR | (1 << intrNum);
}
ClearIntr(intrNum)
int intrNum;
{
custom.intreq = (1 << intrNum);
}
/*
** Structure Functions
*/
struct Interrupt *MakeIntr(name,pri,code,data)
char *name;
int pri;
VOID (*code)();
APTR data;
{
extern struct Interrupt *AllocMem();
register struct Interrupt *intr;
intr = AllocMem(sizeof(struct Interrupt), MEMF_PUBLIC);
if (intr == NULL) return NULL;
intr->is_Node.ln_Pri = pri;
intr->is_Node.ln_Type = NT_INTERRUPT;
intr->is_Node.ln_Name = name;
intr->is_Data = data;
intr->is_Code = code;
return intr;
}
FreeIntr(intr)
register struct Interrupt *intr;
{
if (intr == NULL) return;
if (intr->is_Node.ln_Type != NT_INTERRUPT) return;
intr->is_Node.ln_Type = 0;
FreeMem(intr, sizeof(struct Interrupt));
}
/*
** Handler Functions
*/
extern struct Interrupt *SetIntVector();
struct Interrupt *AddHandler(intrNum,intr)
int intrNum;
struct Interrupt *intr;
{
DisableIntr(intrNum);
ClearIntr(intrNum);
SetIntVector(intrNum,intr); /* ignore result */
}
RemHandler(intrNum,intr)
int intrNum;
register struct Interrupt *intr;
{
register struct Interrupt *retIntr;
if (intr == NULL) return NULL;
/* CRITICAL SECTION: (See text)
** Mutually exclude all tasks and interrupts.
** Remove the handler if it is really ours
** (it could have been replaced already!)
** Disable the interrupt if it is ours.
*/
Disable();
retIntr = SetIntVector(intrNum,NULL);
if (retIntr != intr) SetIntVector(intrNum,retIntr);
else DisableIntr(intrNum);
Enable();
}