242 lines
		
	
	
		
			6.3 KiB
		
	
	
	
		
			ArmAsm
		
	
	
	
	
	
			
		
		
	
	
			242 lines
		
	
	
		
			6.3 KiB
		
	
	
	
		
			ArmAsm
		
	
	
	
	
	
/*
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 *  linux/arch/m68knommu/platform/5307/entry.S
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 *
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 *  Copyright (C) 1999-2007, Greg Ungerer (gerg@snapgear.com)
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 *  Copyright (C) 1998  D. Jeff Dionne <jeff@lineo.ca>,
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 *                      Kenneth Albanowski <kjahds@kjahds.com>,
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 *  Copyright (C) 2000  Lineo Inc. (www.lineo.com)
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 *  Copyright (C) 2004-2006  Macq Electronique SA. (www.macqel.com)
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 *
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 * Based on:
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 *
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 *  linux/arch/m68k/kernel/entry.S
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 *
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 *  Copyright (C) 1991, 1992  Linus Torvalds
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 *
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 * This file is subject to the terms and conditions of the GNU General Public
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 * License.  See the file README.legal in the main directory of this archive
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 * for more details.
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 *
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 * Linux/m68k support by Hamish Macdonald
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 *
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 * 68060 fixes by Jesper Skov
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 * ColdFire support by Greg Ungerer (gerg@snapgear.com)
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 * 5307 fixes by David W. Miller
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 * linux 2.4 support David McCullough <davidm@snapgear.com>
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 * Bug, speed and maintainability fixes by Philippe De Muyter <phdm@macqel.be>
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 */
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#include <linux/sys.h>
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#include <linux/linkage.h>
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#include <asm/unistd.h>
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#include <asm/thread_info.h>
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#include <asm/errno.h>
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#include <asm/setup.h>
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#include <asm/segment.h>
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#include <asm/asm-offsets.h>
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#include <asm/entry.h>
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.bss
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sw_ksp:
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.long	0
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sw_usp:
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.long	0
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.text
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.globl system_call
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.globl resume
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.globl ret_from_exception
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.globl ret_from_signal
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.globl sys_call_table
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.globl ret_from_interrupt
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.globl inthandler
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.globl fasthandler
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enosys:
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	mov.l	#sys_ni_syscall,%d3
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	bra	1f
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ENTRY(system_call)
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	SAVE_ALL
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	move	#0x2000,%sr		/* enable intrs again */
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	cmpl	#NR_syscalls,%d0
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	jcc	enosys
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	lea	sys_call_table,%a0
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	lsll	#2,%d0			/* movel %a0@(%d0:l:4),%d3 */
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	movel	%a0@(%d0),%d3
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	jeq	enosys
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1:
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	movel	%sp,%d2			/* get thread_info pointer */
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	andl	#-THREAD_SIZE,%d2	/* at start of kernel stack */
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	movel	%d2,%a0
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	movel	%a0@,%a1		/* save top of frame */
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	movel	%sp,%a1@(TASK_THREAD+THREAD_ESP0)
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	btst	#(TIF_SYSCALL_TRACE%8),%a0@(TI_FLAGS+(31-TIF_SYSCALL_TRACE)/8)
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	bnes	1f
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	movel	%d3,%a0
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	jbsr	%a0@
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	movel	%d0,%sp@(PT_OFF_D0)	/* save the return value */
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	jra	ret_from_exception
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1:
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	movel	#-ENOSYS,%d2		/* strace needs -ENOSYS in PT_OFF_D0 */
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	movel	%d2,PT_OFF_D0(%sp)	/* on syscall entry */
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	subql	#4,%sp
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	SAVE_SWITCH_STACK
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	jbsr	syscall_trace
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	RESTORE_SWITCH_STACK
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	addql	#4,%sp
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	movel	%d3,%a0
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	jbsr	%a0@
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	movel	%d0,%sp@(PT_OFF_D0)		/* save the return value */
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	subql	#4,%sp			/* dummy return address */
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	SAVE_SWITCH_STACK
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	jbsr	syscall_trace
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ret_from_signal:
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	RESTORE_SWITCH_STACK
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	addql	#4,%sp
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ret_from_exception:
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	move	#0x2700,%sr		/* disable intrs */
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	btst	#5,%sp@(PT_OFF_SR)	/* check if returning to kernel */
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	jeq	Luser_return		/* if so, skip resched, signals */
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#ifdef CONFIG_PREEMPT
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	movel	%sp,%d1			/* get thread_info pointer */
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	andl	#-THREAD_SIZE,%d1	/* at base of kernel stack */
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	movel	%d1,%a0
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	movel	%a0@(TI_FLAGS),%d1	/* get thread_info->flags */
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	andl	#_TIF_NEED_RESCHED,%d1
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	jeq	Lkernel_return
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	movel	%a0@(TI_PREEMPTCOUNT),%d1
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	cmpl	#0,%d1
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	jne	Lkernel_return
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	pea	Lkernel_return
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	jmp	preempt_schedule_irq	/* preempt the kernel */
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#endif
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Lkernel_return:
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	moveml	%sp@,%d1-%d5/%a0-%a2
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	lea	%sp@(32),%sp		/* space for 8 regs */
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	movel	%sp@+,%d0
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	addql	#4,%sp			/* orig d0 */
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	addl	%sp@+,%sp		/* stk adj */
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	rte
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Luser_return:
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	movel	%sp,%d1			/* get thread_info pointer */
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	andl	#-THREAD_SIZE,%d1	/* at base of kernel stack */
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	movel	%d1,%a0
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	movel	%a0@(TI_FLAGS),%d1	/* get thread_info->flags */
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	andl	#_TIF_WORK_MASK,%d1
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	jne	Lwork_to_do		/* still work to do */
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Lreturn:
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	move	#0x2700,%sr		/* disable intrs */
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	movel	sw_usp,%a0		/* get usp */
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	movel	%sp@(PT_OFF_PC),%a0@-	/* copy exception program counter */
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	movel	%sp@(PT_OFF_FORMATVEC),%a0@- /* copy exception format/vector/sr */
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	moveml	%sp@,%d1-%d5/%a0-%a2
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	lea	%sp@(32),%sp		/* space for 8 regs */
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	movel	%sp@+,%d0
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	addql	#4,%sp			/* orig d0 */
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	addl	%sp@+,%sp		/* stk adj */
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	addql	#8,%sp			/* remove exception */
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	movel	%sp,sw_ksp		/* save ksp */
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	subql	#8,sw_usp		/* set exception */
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	movel	sw_usp,%sp		/* restore usp */
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	rte
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Lwork_to_do:
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	movel	%a0@(TI_FLAGS),%d1	/* get thread_info->flags */
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	move	#0x2000,%sr		/* enable intrs again */
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	btst	#TIF_NEED_RESCHED,%d1
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	jne	reschedule
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	/* GERG: do we need something here for TRACEing?? */
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Lsignal_return:
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	subql	#4,%sp			/* dummy return address */
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	SAVE_SWITCH_STACK
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	pea	%sp@(SWITCH_STACK_SIZE)
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	clrl	%sp@-
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	jsr	do_signal
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	addql	#8,%sp
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	RESTORE_SWITCH_STACK
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	addql	#4,%sp
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	jmp	Lreturn
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/*
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 * This is the generic interrupt handler (for all hardware interrupt
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 * sources). Calls upto high level code to do all the work.
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 */
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ENTRY(inthandler)
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	SAVE_ALL
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	moveq	#-1,%d0
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	movel	%d0,%sp@(PT_OFF_ORIG_D0)
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	movew	%sp@(PT_OFF_FORMATVEC),%d0 /* put exception # in d0 */
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	andl	#0x03fc,%d0		/* mask out vector only */
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	movel	%sp,%sp@-		/* push regs arg */
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	lsrl	#2,%d0			/* calculate real vector # */
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	movel	%d0,%sp@-		/* push vector number */
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	jbsr	do_IRQ			/* call high level irq handler */
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	lea	%sp@(8),%sp		/* pop args off stack */
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	bra	ret_from_interrupt	/* this was fallthrough */
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/*
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 * This is the fast interrupt handler (for certain hardware interrupt
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 * sources). Unlike the normal interrupt handler it just uses the
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 * current stack (doesn't care if it is user or kernel). It also
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 * doesn't bother doing the bottom half handlers.
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 */
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ENTRY(fasthandler)
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	SAVE_LOCAL
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	movew	%sp@(PT_OFF_FORMATVEC),%d0
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	andl	#0x03fc,%d0		/* mask out vector only */
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	movel	%sp,%sp@-		/* push regs arg */
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	lsrl	#2,%d0			/* calculate real vector # */
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	movel	%d0,%sp@-		/* push vector number */
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	jbsr	do_IRQ			/* call high level irq handler */
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	lea	%sp@(8),%sp		/* pop args off stack */
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	RESTORE_LOCAL
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ENTRY(ret_from_interrupt)
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	/* the fasthandler is confusing me, haven't seen any user */
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	jmp	ret_from_exception
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/*
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 * Beware - when entering resume, prev (the current task) is
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 * in a0, next (the new task) is in a1,so don't change these
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 * registers until their contents are no longer needed.
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 * This is always called in supervisor mode, so don't bother to save
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 * and restore sr; user's process sr is actually in the stack.
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 */
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ENTRY(resume)
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	movel	%a0, %d1			/* get prev thread in d1 */
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	movel	sw_usp,%d0			/* save usp */
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	movel	%d0,%a0@(TASK_THREAD+THREAD_USP)
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	SAVE_SWITCH_STACK
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	movel	%sp,%a0@(TASK_THREAD+THREAD_KSP) /* save kernel stack pointer */
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	movel	%a1@(TASK_THREAD+THREAD_KSP),%sp /* restore new thread stack */
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	RESTORE_SWITCH_STACK
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	movel	%a1@(TASK_THREAD+THREAD_USP),%a0 /* restore thread user stack */
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	movel	%a0, sw_usp
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	rts
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