NAME    [Toc]    [Back]

     isr_add, isr_add_autovect, isr_add_vectored, isr_add_custom - establish
     interrupt handler

SYNOPSIS    [Toc]    [Back]

     #include <sun3/autoconf.h>
     typedef int (*isr_func_t)(void *);

     void
     isr_add_autovect(isr_func_t fun, void *arg, int level);

     void
     isr_add_vectored(isr_func_t fun, void *arg, int pri, int vec);

     void
     isr_add_custom(int level, void *fun);

DESCRIPTION    [Toc]    [Back]

     The isr_add functions establish interrupt handlers into the system interrupt
 dispatch table and are typically called from device drivers during
     the autoconfiguration process.

     There are two types of interrupts in the Motorola 68000 architecture,
     which differ in the way that an interrupt request is mapped to a dispatch
     function within the interrupt vector table.

     When the CPU detects an asserted signal on one of its interrupt request
     lines, it suspends normal instruction execution and begins an interrupt
     acknowledge cycle on the system bus.  During this cycle the interrupting
     device directs how the CPU is to dispatch its interrupt request.

     If the interrupting device is integrated tightly with the system bus, it
     provides an 8-bit interrupt vector number to the CPU and a vectored
     interrupt occurs.  This vector number points to a vector entry within the
     interrupt vector table to which instruction execution is immediately
     transfered.

     If the interrupting device cannot provide a vector number, it asserts a
     specialized bus line and an autovectored interrupt occurs.  The vector
     number to use is determined by adding the interrupt priority (0-6) to an
     autovector base (typically 18 hexadecimal).

     isr_add_autovect()
                      Adds the function fun to the list of interrupt handlers
                      to be called during an autovectored interrupt of priority
 level.  The pointer arg is passed to the function as
                      its first argument.

     isr_add_vectored()
                      Adds the function fun to the list of interrupt handlers
                      to be called during a vectored interrupts of priority
                      pri at dispatch vector number vec.  The pointer arg is
                      passed to the function as its first argument.

     isr_add_custom()
                      Establish function fun as the interrupt handler for vector
 level.  The autovector base number is automatically
                      added to level.

                      fun is called directly as the dispatch handler and must
                      handle all of the specifics of saving the processor
                      state and returning from a processor exception.  These
                      requirements generally dictate that fun be written in
                      assembler.

CODE REFERENCES    [Toc]    [Back]

     sys/arch/sun3/sun3/isr.c

REFERENCES    [Toc]    [Back]

     MC68030 User's Manual, Third edition, MC68030UM/AD Rev 2, Motorola Inc.

BUGS    [Toc]    [Back]

     There is no way to remove a handler once it has been added.

BSD                              May 21, 1997                              BSD