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/* $NetBSD: makecontext.c,v 1.2 2003/01/18 11:06:24 thorpej Exp $ */
/*-
* Copyright (c) 2001 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Klaus Klein.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <stdlib.h>
#include <stddef.h>
#include <inttypes.h>
#include <ucontext.h>
#include <stdarg.h>
extern void _ctx_start(void);
void
ctx_done(ucontext_t *ucp)
{
if (ucp->uc_link == NULL)
exit(0);
else {
setcontext((const ucontext_t *)ucp->uc_link);
abort();
}
}
__weak_reference(__makecontext, makecontext);
void
__makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...)
{
__greg_t *gr = ucp->uc_mcontext.__gregs;
int i;
unsigned int *sp;
va_list ap;
/* Compute and align stack pointer. */
sp = (unsigned int *)
(((uintptr_t)ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size -
sizeof(double)) & ~7);
/* Allocate necessary stack space for arguments exceeding r0-3. */
if (argc > 4)
sp -= argc - 4;
gr[_REG_SP] = (__greg_t)sp;
/* Wipe out frame pointer. */
gr[_REG_FP] = 0;
/* Arrange for return via the trampoline code. */
gr[_REG_PC] = (__greg_t)_ctx_start;
gr[_REG_R4] = (__greg_t)func;
gr[_REG_R5] = (__greg_t)ucp;
va_start(ap, argc);
/* Pass up to four arguments in r0-3. */
for (i = 0; i < argc && i < 4; i++)
gr[_REG_R0 + i] = va_arg(ap, int);
/* Pass any additional arguments on the stack. */
for (argc -= i; argc > 0; argc--)
*sp++ = va_arg(ap, int);
va_end(ap);
}
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