/*
    Copyright (C) 1995-97 AROS - The Amiga Replacement OS
    $Id: setjmp.s,v 1.2 1997/04/07 22:42:50 ldp Exp $

    Desc: setjmp
    Lang: english
*/

/******************************************************************************

    NAME
#include <setjmp.h>

	int setjmp (jmp_buf env);

    FUNCTION
	Save the current context so that you can return to it later.

    INPUTS
	env - The context/environment is saved here for later restoring

    RESULT
	0 if it returns from setjmp() and 1 when it returns from longjmp().

    NOTES

    EXAMPLE
	jmp_buf env;

	... some code ...

	if (!setjmp (env))
	{
	    ... this code is executed after setjmp() returns ...

	    // This is no good example on how to use this function
	    // You should not do that
	    if (error)
		longjmp (env, 5);

	    ... some code ...
	}
	else
	{
	    ... this code is executed if you call longjmp(env) ...
	}

    BUGS

    SEE ALSO
	longjmp()

    INTERNALS

    HISTORY

******************************************************************************/

	#include "machine.i"

	.text
	.balign 4
	.globl	AROS_CDEFNAME(setjmp)
	.type	AROS_CDEFNAME(setjmp),@function

	.set	FirstArg, 4 /* Skip Return-Adress */
	.set	env, FirstArg
	.set	retaddr, 0

AROS_CDEFNAME(setjmp):
	move.l	env(sp),a0		/* save area pointer */
	move.l	retaddr(sp),(a0)+	/* save old PC */
	lea	env(sp),a1		/* adjust saved SP since we won't rts */
	move.l	a1,(a0)+		/* save old SP */
	movem.l	d2-d7/a2-a6,(a0)	/* save remaining non-scratch regs */
	clr.l	d0			/* return 0 */
	rts

/*
	The jmp_buf is filled as follows (d0/d1/a0/a1 are not saved):

	_jmp_buf	offset	contents
	[0]   		0	old pc
	[1]		4	old sp
	[2]		8	d2
	[3]		12	d3
	[4]		16	d4
	[5]		20	d5
	[6]		24	d6
	[7]		28	d7
	[8]		32	a2
	[9]		36	a3
	[10]		40	a4
	[11]		44	a5
	[12]		48	a6
*/