minix/lib/libc/arch/hppa/gen/makecontext.c

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/* $NetBSD: makecontext.c,v 1.6 2012/03/22 12:31:32 skrll 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 1.6 2012/03/22 12:31:32 skrll Exp $");
#endif
#include <inttypes.h>
#include <stddef.h>
#include <ucontext.h>
#include "extern.h"
#include <stdarg.h>
#include <sys/types.h>
#include <machine/frame.h>
void __resumecontext(void) __dead;
void
makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...)
{
__greg_t *gr = ucp->uc_mcontext.__gregs;
__greg_t *gp, rp, fp;
register __greg_t dp __asm("r27");
uintptr_t *sp;
int i;
va_list ap;
/* LINTED uintptr_t is safe */
sp = (uintptr_t *)ucp->uc_stack.ss_sp;
/* LINTED uintptr_t is safe */
sp += 16; /* standard frame */
sp += (argc >= 4 ? argc : 4); /* Make room for >=4 arguments. */
sp = (uintptr_t *)
((uintptr_t)(sp + 16) & ~0x3f); /* Align on 64-byte boundary. */
/* Save away the registers that we'll need. */
gr[_REG_SP] = (__greg_t)sp;
rp = (__greg_t)__resumecontext;
if (rp & 2) {
gp = (__greg_t *)(rp & ~3);
rp = gp[0];
sp[-8] = gp[1];
}
gr[_REG_RP] = rp;
fp = (__greg_t)func;
if (fp & 2) {
gp = (__greg_t *)(fp & ~3);
fp = gp[0];
gr[_REG_R19] = gp[1];
}
gr[_REG_PCOQH] = fp | HPPA_PC_PRIV_USER;
gr[_REG_PCOQT] = (fp + 4) | HPPA_PC_PRIV_USER;
/* LINTED dp is reg27, ref. above, so initialized */
gr[_REG_DP] = dp;
/* Construct argument list. */
va_start(ap, argc);
/* Up to the first four arguments are passed in %arg0-3. */
for (i = 0; i < argc && i < 4; i++) {
/* LINTED uintptr_t is safe */
gr[_REG_ARG0 - i] = va_arg(ap, uintptr_t);
}
/* Pass remaining arguments on the stack below the %arg0-3 gap. */
for (; i < argc; i++) {
/* LINTED uintptr_t is safe */
sp[-9 - i] = va_arg(ap, uintptr_t);
}
va_end(ap);
}