EMILE/second/head.S

/*
 *
 * (c) 2004, 2005 Laurent Vivier <Laurent@lvivier.info>
 *
 */

	.cpu 68000

.macro SysError
	.short 0xA9C9
.endm

.macro NewPtrClear
        .short 0xA31E
.endm

.equ	paramstring_length, 1024

/***************************************************************************
 *
 * second level arguments 
 *
 ***************************************************************************/

_start:			bra	setup
_signature:		.dc.b	'E','M','0','7'

/* EM06 */

_conf_size:		.dc.w	paramstring_length
_configuration:		.skip	paramstring_length, 0

	.align	4
setup:
	/* relocate C code, need to be compiled with -fpic */

	bsr	relocate

	/* begin to work */

	lea	_start(%pc), %a0
	move.l	%a0, -(%sp)
	bsr	start@PLTPC

	/* We guess to never come here */
loop:
	bra	loop

relocate:
	/* Allocate BSS section */

	move.l	#__bss_size, %d0	/* size */
	/* Alloc and clear memory (needed by GCC 3) */
	NewPtrClear			/* result in %a0 */
	move.l	%a0, %d0
	bne	malloc_ok
	SysError
malloc_ok:
	move.l	%a0,%d3
	move.l	#__bss_start, %d0
	sub.l	%d0,%d3			/* %d3 is the offset to add for BSS */

	/* real address of GOT */

	lea	_GLOBAL_OFFSET_TABLE_-.-8,%a0
	lea	(%pc, %a0), %a0

	/* linked address of GOT */

	move.l	#_GLOBAL_OFFSET_TABLE_, %d0

	/* %d2 is the offset to add for all other sections */

	move.l	%a0,%d2
	sub.l	%d0,%d2

	/* relocate BSS section */

	move.l	#__got_size, %d0
	beq	exit_relocate

got_loop:
	move.l	(%a0), %d1

	cmp.l	#__bss_start.l, %d1
	blt	other_section
	cmp.l	#_end.l, %d1
	bgt	other_section

	/* symbol in section BSS */

	add.l	%d3, %d1
	bra	got_store

other_section:
	add.l	%d2, %d1

got_store:
	move.l	%d1, (%a0)+

	subq.l	#4, %d0
	bgt	got_loop

exit_relocate:
	rts
Initial revision 2004-02-15 20:46:45 +00:00			`/*`
			`*`
Change my email address to Laurent@lvivier.info 2006-09-15 14:55:39 +00:00			`* (c) 2004, 2005 Laurent Vivier <Laurent@lvivier.info>`
Initial revision 2004-02-15 20:46:45 +00:00			`*`
			`*/`

change .chip to .cpu to use binutils 2.17 2007-03-22 15:36:39 +00:00			`.cpu 68000`
Add 68000 support 2005-05-17 23:36:26 +00:00
check result of NewPtr and invoke SysError if needed 2004-08-18 23:14:55 +00:00			`.macro SysError`
			`.short 0xA9C9`
			`.endm`

GCC 3 requires BSS be cleared: it places variables initialized to 0 from DATA to BSS 2005-06-06 19:33:40 +00:00			`.macro NewPtrClear`
			`.short 0xA31E`
Allocate and relocate section BSS 2004-05-25 20:12:52 +00:00			`.endm`

EM06 header type: all is stored as text 2005-11-27 22:31:07 +00:00			`.equ paramstring_length, 1024`
Allow to set kernel command line 2004-05-19 00:09:58 +00:00
Enhance second stage header 2004-05-26 23:05:35 +00:00			`/***************************************************************************`
			`*`
			`* second level arguments`
			`*`
			`***************************************************************************/`

Add serial configuration information in header 2004-06-22 21:24:54 +00:00			`_start: bra setup`
change signature to EM07 to support config file 2007-05-12 19:33:25 +00:00			`_signature: .dc.b 'E','M','0','7'`
switch to EM04, add scsi support -> kernel_image_offset is container offset 2004-12-03 00:21:25 +00:00
EM06 header type: all is stored as text 2005-11-27 22:31:07 +00:00			`/* EM06 */`
switch to EM04, add scsi support -> kernel_image_offset is container offset 2004-12-03 00:21:25 +00:00
EM06 header type: all is stored as text 2005-11-27 22:31:07 +00:00			`_conf_size: .dc.w paramstring_length`
			`_configuration: .skip paramstring_length, 0`
Allow to set kernel command line 2004-05-19 00:09:58 +00:00
			`.align 4`
			`setup:`
Allocate and relocate section BSS 2004-05-25 20:12:52 +00:00			`/* relocate C code, need to be compiled with -fpic */`
Make second level relocatable using -fpic and "GLOBAL_OFFSET_TABLE" should be improved by using -mrelpc, but this flags is only supported by gcc > 3.0 (and I use gcc 2.95) 2004-05-24 23:59:13 +00:00
			`bsr relocate`

Initial revision 2004-02-15 20:46:45 +00:00			`/* begin to work */`

Add serial configuration information in header 2004-06-22 21:24:54 +00:00			`lea _start(%pc), %a0`
Pass booter info by args of start() 2004-06-03 19:30:26 +00:00			`move.l %a0, -(%sp)`
			`bsr start@PLTPC`
Initial revision 2004-02-15 20:46:45 +00:00
			`/* We guess to never come here */`
			`loop:`
			`bra loop`
Make second level relocatable using -fpic and "GLOBAL_OFFSET_TABLE" should be improved by using -mrelpc, but this flags is only supported by gcc > 3.0 (and I use gcc 2.95) 2004-05-24 23:59:13 +00:00
			`relocate:`
Allocate and relocate section BSS 2004-05-25 20:12:52 +00:00			`/* Allocate BSS section */`

			`move.l #__bss_size, %d0 /* size */`
GCC 3 requires BSS be cleared: it places variables initialized to 0 from DATA to BSS 2005-06-06 19:33:40 +00:00			`/* Alloc and clear memory (needed by GCC 3) */`
			`NewPtrClear /* result in %a0 */`
check result of NewPtr and invoke SysError if needed 2004-08-18 23:14:55 +00:00			`move.l %a0, %d0`
			`bne malloc_ok`
			`SysError`
			`malloc_ok:`
Allocate and relocate section BSS 2004-05-25 20:12:52 +00:00			`move.l %a0,%d3`
			`move.l #__bss_start, %d0`
			`sub.l %d0,%d3 /* %d3 is the offset to add for BSS */`

Make second level relocatable using -fpic and "GLOBAL_OFFSET_TABLE" should be improved by using -mrelpc, but this flags is only supported by gcc > 3.0 (and I use gcc 2.95) 2004-05-24 23:59:13 +00:00			`/* real address of GOT */`

68000 compatibility: load _GLOBAL_OFFSET_TABLE_ 2005-06-10 20:53:14 +00:00			`lea _GLOBAL_OFFSET_TABLE_-.-8,%a0`
			`lea (%pc, %a0), %a0`
Make second level relocatable using -fpic and "GLOBAL_OFFSET_TABLE" should be improved by using -mrelpc, but this flags is only supported by gcc > 3.0 (and I use gcc 2.95) 2004-05-24 23:59:13 +00:00
			`/* linked address of GOT */`

			`move.l #_GLOBAL_OFFSET_TABLE_, %d0`

Allocate and relocate section BSS 2004-05-25 20:12:52 +00:00			`/* %d2 is the offset to add for all other sections */`
Make second level relocatable using -fpic and "GLOBAL_OFFSET_TABLE" should be improved by using -mrelpc, but this flags is only supported by gcc > 3.0 (and I use gcc 2.95) 2004-05-24 23:59:13 +00:00
			`move.l %a0,%d2`
			`sub.l %d0,%d2`

Allocate and relocate section BSS 2004-05-25 20:12:52 +00:00			`/* relocate BSS section */`

			`move.l #__got_size, %d0`
Make second level relocatable using -fpic and "GLOBAL_OFFSET_TABLE" should be improved by using -mrelpc, but this flags is only supported by gcc > 3.0 (and I use gcc 2.95) 2004-05-24 23:59:13 +00:00			`beq exit_relocate`

			`got_loop:`
			`move.l (%a0), %d1`
Allocate and relocate section BSS 2004-05-25 20:12:52 +00:00
arch_init must be before init_memory_map, console_init can be the first call 2004-05-25 23:16:56 +00:00			`cmp.l #__bss_start.l, %d1`
Allocate and relocate section BSS 2004-05-25 20:12:52 +00:00			`blt other_section`
arch_init must be before init_memory_map, console_init can be the first call 2004-05-25 23:16:56 +00:00			`cmp.l #_end.l, %d1`
Allocate and relocate section BSS 2004-05-25 20:12:52 +00:00			`bgt other_section`

			`/* symbol in section BSS */`

			`add.l %d3, %d1`
			`bra got_store`

			`other_section:`
Make second level relocatable using -fpic and "GLOBAL_OFFSET_TABLE" should be improved by using -mrelpc, but this flags is only supported by gcc > 3.0 (and I use gcc 2.95) 2004-05-24 23:59:13 +00:00			`add.l %d2, %d1`
Allocate and relocate section BSS 2004-05-25 20:12:52 +00:00
			`got_store:`
Make second level relocatable using -fpic and "GLOBAL_OFFSET_TABLE" should be improved by using -mrelpc, but this flags is only supported by gcc > 3.0 (and I use gcc 2.95) 2004-05-24 23:59:13 +00:00			`move.l %d1, (%a0)+`
Allocate and relocate section BSS 2004-05-25 20:12:52 +00:00
Make second level relocatable using -fpic and "GLOBAL_OFFSET_TABLE" should be improved by using -mrelpc, but this flags is only supported by gcc > 3.0 (and I use gcc 2.95) 2004-05-24 23:59:13 +00:00			`subq.l #4, %d0`
			`bgt got_loop`

			`exit_relocate:`
			`rts`