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linux_sig_machdep.S revision 1.1 
      1 /*	$NetBSD: linux_sig_machdep.S,v 1.1 1998/12/15 19:25:40 itohy Exp $	*/
      2 
      3 /*
      4  * Written by ITOH Yasufumi.
      5  * Public domain.
      6  */
      7 
      8 #include <m68k/asm.h>
      9 #include <compat/linux/linux_syscall.h>
     10 
     11 /*
     12  * __dead void linux_reenter_syscall(struct frame *fp, int stkadj)
     13  *					__attribute__((__noreturn__));
     14  *
     15  * Move stack frame by stkadj bytes and re-enter syscall().
     16  *
     17  * XXX This is a kludge.
     18  */
     19 
     20 ENTRY_NOPROFILE(linux_reenter_syscall)
     21 	addql	#4,sp			| pop PC
     22 	movel	sp@+,a0			| current frame addr
     23 	movel	sp@,d1			| stkadj
     24 
     25 | The m68k frame (struct trapframe) format:
     26 |	16:l	d0-d7/a0-a6/usp
     27 |	1:w	(pad)
     28 |	1:w	stkadj
     29 |	1:w	sr
     30 |	1:l	pc
     31 |	1:w	format/vector
     32 
     33 	moveal	a0,a1
     34 	subal	d1,a1			| new frame address
     35 	moveal	a1,sp			| set SP
     36 
     37 	| copy down frame (16*4 + 2 + 2 + 2 + 4 + 2 = 76 bytes = 19 longs)
     38 	moveq	#19-1,d0
     39 Lcpfr:	movel	a0@+,a1@+
     40 	dbra	d0,Lcpfr
     41 
     42 	movew	d1,sp@(16*4+2)		| set stack adjust count
     43 	movel	sp@,sp@-		| push syscall no (original d0 value)
     44 	jbsr	_C_LABEL(syscall)	| re-enter syscall()
     45 	addql	#4,sp			| pop syscall no
     46 #ifdef DEBUG
     47 	tstw	sp@(16*4+2)		| stack adjust must be zero
     48 	jeq	Ladjzero
     49 	PANIC("linux_reenter_syscall")
     50 Ladjzero:
     51 #endif
     52 	moveal	sp@(15*4),a0		| grab and restore
     53 	movel	a0,usp			|   user SP
     54 	moveml	sp@+,#0x7FFF		| restore user registers
     55 	addql	#8,sp			| pop SP and stack adjust
     56 	jra	_ASM_LABEL(rei)		| rte
     57 
     58 /*
     59  * Signal "trampoline" code for Linux emulation.
     60  * The sigtramp for Linux/m68k is on the stack frame, and this is a dummy.
     61  */
     62 	.align	2
     63 GLOBAL(linux_sigcode)
     64 	moveq	#LINUX_SYS_exit,d0	| _exit(?)
     65 	trap	#0
     66 	.align	2
     67 GLOBAL(linux_esigcode)
     68