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/*
* Intel i386 Dependent Source
*
*
* COPYRIGHT (c) 1989, 1990, 1991, 1992, 1993, 1994.
* On-Line Applications Research Corporation (OAR).
* All rights assigned to U.S. Government, 1994.
*
* This material may be reproduced by or for the U.S. Government pursuant
* to the copyright license under the clause at DFARS 252.227-7013. This
* notice must appear in all copies of this file and its derivatives.
*
* $Id$
*/
#include <rtems/system.h>
#include <rtems/fatal.h>
#include <rtems/isr.h>
#include <rtems/wkspace.h>
/* _CPU_Initialize
*
* This routine performs processor dependent initialization.
*
* INPUT PARAMETERS:
* cpu_table - CPU table to initialize
* thread_dispatch - address of disptaching routine
*/
void _CPU_Initialize(
rtems_cpu_table *cpu_table,
void (*thread_dispatch) /* ignored on this CPU */
)
{
register unsigned16 fp_status asm ("ax");
register unsigned8 *fp_context;
if ( cpu_table == NULL )
rtems_fatal_error_occurred( RTEMS_NOT_CONFIGURED );
_CPU_Table = *cpu_table;
/*
* The following code saves a NULL i387 context which is given
* to each task at start and restart time. The following code
* is based upon that provided in the i386 Programmer's
* Manual and should work on any coprocessor greater than
* the i80287.
*
* NOTE: The NO RTEMS_WAIT form of the coprocessor instructions
* MUST be used in case there is not a coprocessor
* to wait for.
*/
fp_status = 0xa5a5;
asm volatile( "fninit" );
asm volatile( "fnstsw %0" : "=a" (fp_status) : "0" (fp_status) );
if ( fp_status == 0 ) {
fp_context = _CPU_Null_fp_context;
asm volatile( "fsave (%0)" : "=r" (fp_context)
: "0" (fp_context)
);
}
}
/* _CPU_ISR_install_vector
*
* This kernel routine installs the RTEMS handler for the
* specified vector.
*
* Input parameters:
* vector - interrupt vector number
* old_handler - former ISR for this vector number
* new_handler - replacement ISR for this vector number
*
* Output parameters: NONE
*
*/
void _ISR_Handler_0(), _ISR_Handler_1();
#define PER_ISR_ENTRY \
(((unsigned32) _ISR_Handler_1 - (unsigned32) _ISR_Handler_0))
#define _Interrupt_Handler_entry( _vector ) \
(((unsigned32)_ISR_Handler_0) + ((_vector) * PER_ISR_ENTRY))
void _CPU_ISR_install_vector(
unsigned32 vector,
proc_ptr new_handler,
proc_ptr *old_handler
)
{
i386_IDT_slot idt;
unsigned32 unique_handler;
/* calculate the unique entry point for this vector */
unique_handler = _Interrupt_Handler_entry( vector );
/* build the IDT entry */
idt.offset_0_15 = ((unsigned32) unique_handler) & 0xffff;
idt.segment_selector = i386_get_cs();
idt.reserved = 0x00;
idt.p_dpl = 0x8e; /* present, ISR */
idt.offset_16_31 = ((unsigned32) unique_handler) >> 16;
/* install the IDT entry */
i386_Install_idt(
(unsigned32) &idt,
_CPU_Table.interrupt_table_segment,
(unsigned32) _CPU_Table.interrupt_table_offset + (8 * vector)
);
/* "portable" part */
*old_handler = _ISR_Vector_table[ vector ];
_ISR_Vector_table[ vector ] = new_handler;
}
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