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awilliam
GitHub Repository: awilliam/linux-vfio
 Path: blob/master/arch/m68k/platform/68328/head-de2.S
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#define	MEM_END	0x00800000	/* Memory size 8Mb */

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#undef CRT_DEBUG

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.macro	PUTC CHAR

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#ifdef CRT_DEBUG

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	moveq	#\CHAR, %d7

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	jsr	putc

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#endif

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.endm

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	.global	_start

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	.global _rambase

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	.global _ramvec

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	.global	_ramstart

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	.global	_ramend

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	.data

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/*

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 *	Set up the usable of RAM stuff

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 */

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_rambase:

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	.long	0

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_ramvec:

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	.long	0

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_ramstart:

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	.long	0

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_ramend:

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	.long	0

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	.text

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_start:

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/*

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 * Setup initial stack

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 */

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	/* disable all interrupts */

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	movew	#0x2700, %sr

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	movel	#-1, 0xfffff304

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	movel	#MEM_END-4, %sp

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	PUTC	'\r'

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	PUTC	'\n'

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	PUTC	'A'

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	PUTC	'B'

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/*

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 *	Determine end of RAM

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 */

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	movel	#MEM_END, %a0

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	movel	%a0, _ramend

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	PUTC	'C'

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/*

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 *	Move ROM filesystem above bss :-)

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 */

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	moveal	#_sbss, %a0			/* romfs at the start of bss */

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	moveal	#_ebss, %a1			/* Set up destination  */

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	movel	%a0, %a2			/* Copy of bss start */

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	movel	8(%a0), %d1			/* Get size of ROMFS */

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	addql	#8, %d1				/* Allow for rounding */

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	andl	#0xfffffffc, %d1	/* Whole words */

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	addl	%d1, %a0			/* Copy from end */

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	addl	%d1, %a1			/* Copy from end */

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	movel	%a1, _ramstart		/* Set start of ram */

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1:

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	movel	-(%a0), %d0			/* Copy dword */

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	movel	%d0, -(%a1)

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	cmpl	%a0, %a2			/* Check if at end */

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	bne	1b

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	PUTC	'D'

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/*

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 * Initialize BSS segment to 0

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 */

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	lea	_sbss, %a0

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	lea	_ebss, %a1

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	/* Copy 0 to %a0 until %a0 == %a1 */

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2:	cmpal	%a0, %a1

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	beq	1f

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	clrl	(%a0)+

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	bra	2b

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1:

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	PUTC	'E'

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/*

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 * Load the current task pointer and stack

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 */

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	lea	init_thread_union, %a0

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	lea	0x2000(%a0), %sp

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	PUTC	'F'

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	PUTC	'\r'

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	PUTC	'\n'

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/*

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 * Go

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 */

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	jmp	start_kernel

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/*

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 * Local functions

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 */

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#ifdef CRT_DEBUG

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putc:

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	moveb	%d7, 0xfffff907

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1:

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	movew	0xfffff906, %d7

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	andw	#0x2000, %d7

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	beq	1b

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	rts

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#endif

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