path: root/c/src/lib/libbsp/i386/i386ex/startup/linkcmds

/*
 *  This file contains directives for the GNU linker which are specific
 *  to the Intel 386ex evaluation board.
 *
 *  COPYRIGHT (c) 1989-1998.
 *  On-Line Applications Research Corporation (OAR).
 *  Copyright assigned to U.S. Government, 1994.
 *
 *  The license and distribution terms for this file may be
 *  found in the file LICENSE in this distribution or at
 *  http://www.OARcorp.com/rtems/license.html.
 *
 *  $Id$
 * 
 * Memory layout:
 *
 * 0x3f80000 -> 0x3ff0000 : text section
 * 0x3ff0000 -> 0x3ff0028 : global descriptor table in ROM
 * 0x3ff0028 -> 0x3fff000 : data section ( copied by start.s to RAM )
 * 0x3fff000 -> 0x3fffff0 : initial section ( init 386ex, goto protected mode, copy ROM-RAM ) 
 * 0x3fffff0 -> 0x4000000 : reset section ( jmp to initial only )
 */

	ENTRY(reset) ;
SECTIONS
{

/****************************************************************************************
 * data section:
 *
 * This section defines the locations of the data section in ROM as well as in RAM.  
 * start.s copies the data section to RAM in real mode.  This is done PRIOR to the lgdt
 * instruction since the data section contains the Global_descriptor_table and GDTR.
 ***********************************************************************************/

	_rom_data_start = 0x3ff0000;

	_rom_data_segment   = 0xF000; 
	_rom_data_offset    = 0x0; 

	_ram_data_segment   = 0x0000 ;
	_ram_data_offset    = 0x0;
	_ram_data_location  = _ram_data_segment * 16 + _ram_data_offset;

        .data  : 
        AT ( _rom_data_start ) 
        {
        _sdata = .;
        *(.data);
        _edata = .;
   	}
        _data_start       = ADDR(.data) ;
	 data_start       = _data_start ;
        _data_size        = _edata - _sdata ;

/**************************************************************************************
 * bss section:
 *
 * The bss section is the last section in RAM.  
 *************************************************************************************/
	_edata = ALIGN( 0x10 );  
	.bss :
	{
	_bss_start = .;
	*(.bss);
	*(COMMON);
	_ebss = ALIGN(0x10);
	end = _ebss;
	_end = end;
	__end = end;
	}
        _bss_size   = _ebss - _bss_start ;

/**************************************************************************************
 * General variables:
 *
 * The stack_size variable is customizable here.  The heap is located directly after
 * The stack in RAM.  A routine within bspstart.c uses these variables to ensure that
 * the heap used by RTEMS is as large as the RAM remaining after all workspace configurations 
 * are complete.
 *************************************************************************************/
        stack_size  = 0x8000 ;
	stack_origin = end + stack_size ;
	heap_bottom  = stack_origin + 4 ;  

/***************************************************************************************
 * text section:
 *
 * This section is NOT copied into RAM.  It is left in ROM, as the flash ROM is quick enough.
 ***************************************************************************************/
        .text ( 0x3f80000 ):
        {
         CREATE_OBJECT_SYMBOLS
	text_start = . ;
        _text_start = . ;
        *(.text ) ;
	. = ALIGN (16);

	*(.eh_fram)
	. = ALIGN (16);

	/*
	 * C++ constructors
	 */
	__CTOR_LIST__ = .;
	LONG((__CTOR_END__ - __CTOR_LIST__) / 4 - 2)
	*(.ctors)
	LONG(0)
	__CTOR_END__ = .;
	. = ALIGN (4) ;
	__DTOR_LIST__ = .;
	LONG((__DTOR_END__ - __DTOR_LIST__) / 4 - 2)
	*(.dtors)
	LONG(0)
	__DTOR_END__ = .;
	_rodata_start 5 . ;
	*(.rodata)
	*(.gnu.linkonce.r*)
	_erodata = ALIGN( 0x10 ) ;
        _etext = ALIGN( 0x10 );
	_endtext = . ; 
        }

/*******************************************************************************************
 * initial section:
 *
 * This section is defined after the data section.  It must be in the top 64K of memory
 * to enable the initial short jmp from the reset section while still in real-mode. It 
 * initializes the i386ex, moves the gdt from ROM to RAM,loads the gdt,
 * jumps to protected mode, copies the data section from ROM to RAM and loads the idt.
 ******************************************************************************************/

	.initial _rom_data_start + _data_size :
	{
	*(.initial);
	}

/*******************************************************************************************
 * board reset section:
 *
 * This section contains the short jmp from the reset section to the initial section.  It is 
 * the first code executed on reset/power on.
 ******************************************************************************************/

	.reset 0x3fffff0:
	{
	*(.reset);
        }
}