source: rtems/doc/supplements/i386/cputable.t @ db91520

@c
@c  COPYRIGHT (c) 1988-1997.
@c  On-Line Applications Research Corporation (OAR).
@c  All rights reserved.
@c
@c  $Id$
@c

@ifinfo
@node Processor Dependent Information Table, Processor Dependent Information Table Introduction, Board Support Packages Processor Initialization, Top
@end ifinfo
@chapter Processor Dependent Information Table
@ifinfo
@menu
* Processor Dependent Information Table Introduction::
* Processor Dependent Information Table CPU Dependent Information Table::
@end menu
@end ifinfo

@ifinfo
@node Processor Dependent Information Table Introduction, Processor Dependent Information Table CPU Dependent Information Table, Processor Dependent Information Table, Processor Dependent Information Table
@end ifinfo
@section Introduction

Any highly processor dependent information required
to describe a processor to RTEMS is provided in the CPU
Dependent Information Table.  This table is not required for all
processors supported by RTEMS.  This chapter describes the
contents, if any, for a particular processor type.

@ifinfo
@node Processor Dependent Information Table CPU Dependent Information Table, Memory Requirements, Processor Dependent Information Table Introduction, Processor Dependent Information Table
@end ifinfo
@section CPU Dependent Information Table

The i386 version of the RTEMS CPU Dependent
Information Table contains the information required to interface
a Board Support Package and RTEMS on the i386.  This information
is provided to allow RTEMS to interoperate effectively with the
BSP.  The C structure definition is given here:

@example
@group
typedef struct @{
  void       (*pretasking_hook)( void );
  void       (*predriver_hook)( void );
  void       (*idle_task)( void );
  boolean      do_zero_of_workspace;
  unsigned32   interrupt_stack_size;
  unsigned32   extra_mpci_receive_server_stack;
  void *     (*stack_allocate_hook)( unsigned32 );
  void       (*stack_free_hook)( void* );
  /* end of fields required on all CPUs */
 
  unsigned32   interrupt_segment;
  void        *interrupt_vector_table;
@} rtems_cpu_table;
@end group
@end example

@table @code
@item pretasking_hook
is the address of the
user provided routine which is invoked once RTEMS initialization
is complete but before interrupts and tasking are enabled.  This
field may be NULL to indicate that the hook is not utilized.

@item predriver_hook
is the address of the user provided
routine which is invoked with tasking enabled immediately before
the MPCI and device drivers are initialized. RTEMS
initialization is complete, interrupts and tasking are enabled,
but no device drivers are initialized.  This field may be NULL to
indicate that the hook is not utilized.

@item postdriver_hook
is the address of the user provided
routine which is invoked with tasking enabled immediately after
the MPCI and device drivers are initialized. RTEMS
initialization is complete, interrupts and tasking are enabled,
and the device drivers are initialized.  This field may be NULL
to indicate that the hook is not utilized.

@item idle_task
is the address of the optional user
provided routine which is used as the system's IDLE task.  If
this field is not NULL, then the RTEMS default IDLE task is not
used.  This field may be NULL to indicate that the default IDLE
is to be used.

@item do_zero_of_workspace
indicates whether RTEMS should
zero the Workspace as part of its initialization.  If set to
TRUE, the Workspace is zeroed.  Otherwise, it is not.

@item interrupt_stack_size
is the size of the RTEMS
allocated interrupt stack in bytes.  This value must be at least
as large as MINIMUM_STACK_SIZE.

@item extra_mpci_receive_server_stack
is the extra stack space allocated for the RTEMS MPCI receive server task
in bytes.  The MPCI receive server may invoke nearly all directives and 
may require extra stack space on some targets.

@item stack_allocate_hook
is the address of the optional user provided routine which allocates 
memory for task stacks.  If this hook is not NULL, then a stack_free_hook
must be provided as well.

@item stack_free_hook
is the address of the optional user provided routine which frees 
memory for task stacks.  If this hook is not NULL, then a stack_allocate_hook
must be provided as well.

@item interrupt_segment
is the value of the selector which should be placed in a segment 
register to access the Interrupt Descriptor Table.

@item interrupt_vector_table
is the base address of the Interrupt Descriptor Table relative to the 
interrupt_segment.

@end table

The contents of the i386 Interrupt Descriptor Table
are discussed in  Intel's i386 User's Manual.  Structure
definitions for the i386 IDT is provided by including the file
rtems.h.