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/* $NetBSD: makecontext.c,v 1.7 2011/09/20 08:42:29 joerg 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>
#if defined(LIBC_SCCS) && !defined(lint)
__RCSID("$NetBSD: makecontext.c,v 1.7 2011/09/20 08:42:29 joerg Exp $");
#endif
#include <inttypes.h>
#include <stddef.h>
#include <ucontext.h>
#include "extern.h"
#include <stdarg.h>
void __resumecontext(void) __dead;
void
makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...)
{
__greg_t *gr = ucp->uc_mcontext.__gregs;
__greg_t *sp;
int i;
va_list ap;
/* LINTED uintptr_t is safe */
sp = (__greg_t *)
((uintptr_t)ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size);
/* LINTED uintptr_t is safe */
#if defined(__mips_o32) || defined(__mips_o64)
sp -= (argc >= 4 ? argc : 4); /* Make room for >=4 arguments. */
sp = (__greg_t *)
((uintptr_t)sp & ~0x7); /* Align on double-word boundary. */
#elif defined(__mips_n32) || defined(__mips_n64)
sp -= (argc > 8 ? argc - 8 : 0); /* Make room for > 8 arguments. */
sp = (__greg_t *)
((uintptr_t)sp & ~0xf); /* Align on quad-word boundary. */
#endif
gr[_REG_SP] = (intptr_t)sp;
gr[_REG_RA] = (intptr_t)__resumecontext;
gr[_REG_T9] = (intptr_t)func; /* required for .abicalls */
gr[_REG_EPC] = (intptr_t)func;
/* Construct argument list. */
va_start(ap, argc);
#if defined(__mips_o32) || defined(__mips_o64)
/* Up to the first four arguments are passed in $a0-3. */
for (i = 0; i < argc && i < 4; i++)
/* LINTED __greg_t is safe */
gr[_REG_A0 + i] = va_arg(ap, __greg_t);
/* Pass remaining arguments on the stack above the $a0-3 gap. */
sp += i;
#endif
#if defined(__mips_n32) || defined(__mips_n64)
/* Up to the first 8 arguments are passed in $a0-7. */
for (i = 0; i < argc && i < 8; i++)
/* LINTED __greg_t is safe */
gr[_REG_A0 + i] = va_arg(ap, __greg_t);
/* Pass remaining arguments on the stack above the $a0-3 gap. */
#endif
/* Pass remaining arguments on the stack above the $a0-3 gap. */
for (; i < argc; i++)
/* LINTED uintptr_t is safe */
*sp++ = va_arg(ap, __greg_t);
va_end(ap);
}
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