source: rtems/doc/supplements/i386/cputable.t @ 01f46a73

@c
@c  COPYRIGHT (c) 1988-2002.
@c  On-Line Applications Research Corporation (OAR).
@c  All rights reserved.
@c
@c  $Id$
@c

@chapter Processor Dependent Information Table

@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.

@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   idle_task_stack_size;
  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 APIs are initialized.  This routine will be invoked
before any system tasks are created.  Interrupts are disabled.
This field may be NULL to indicate that the hook is not utilized.

@item predriver_hook
is the address of the user provided
routine that is invoked immediately before the
the device drivers and MPCI are initialized. RTEMS
initialization is complete but interrupts and tasking are disabled.
This field may be NULL to indicate that the hook is not utilized.

@item postdriver_hook
is the address of the user provided
routine that is invoked immediately after the
the device drivers and MPCI are initialized. RTEMS
initialization is complete but interrupts and tasking are disabled.
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 idle_task_stack_size
is the size of the RTEMS idle task stack in bytes.  
If this number is less than MINIMUM_STACK_SIZE, then the 
idle task's stack will be MINIMUM_STACK_SIZE in byte.

@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.