lib/libc/arch/sparc64/gen/makecontext.c

   1 /*      $NetBSD: makecontext.c,v 1.3 2006/05/11 00:34:44 mrg Exp $      */
   2
   3 /*-
   4  * Copyright (c) 2001 The NetBSD Foundation, Inc.
   5  * All rights reserved.
   6  *
   7  * This code is derived from software contributed to The NetBSD Foundation
   8  * by Klaus Klein.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  29  * POSSIBILITY OF SUCH DAMAGE.
  30  */
  31
  32 #include <sys/cdefs.h>
  33 #if defined(LIBC_SCCS) && !defined(lint)
  34 __RCSID("$NetBSD: makecontext.c,v 1.3 2006/05/11 00:34:44 mrg Exp $");
  35 #endif
  36
  37 #include <inttypes.h>
  38 #include <stddef.h>
  39 #include <sys/types.h>
  40 #include <ucontext.h>
  41 #include "extern.h"
  42
  43 #include <stdarg.h>
  44
  45 void
  46 makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...)
  47 {
  48         __greg_t *gr = ucp->uc_mcontext.__gregs;
  49         int i;
  50         ulong *sp;
  51         va_list ap;
  52
  53         sp = (ulong *)((caddr_t)ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size);
  54         /* Align on quad-word boundary. */
  55         sp = (ulong *)((ulong)sp & ~0xf);
  56
  57         /* Make room for: argx, argd, struct return pointer(?), rwindow. */
  58         sp -= (argc > 6 ? argc - 6 : 0) + 6 + 8 + 8;
  59
  60         va_start(ap, argc);
  61
  62         /* Pass up to 6 arguments in %o0-5. */
  63         for (i = 0; i < argc && i < 6; i++)
  64                 gr[_REG_O0 + i] = sp[i + 16] = va_arg(ap, unsigned long);
  65
  66         /* Pass any additional arguments on the stack. */
  67         for (; i < argc; i++)
  68                 sp[i + 16] = va_arg(ap, unsigned long);
  69         va_end(ap);
  70
  71         sp[14] = (ulong)sp - 2047;
  72         sp[15] = (ulong)_resumecontext - 8;
  73
  74         sp = (ulong *)((caddr_t)sp - 2047);
  75
  76         gr[_REG_O6] = (__greg_t)sp;
  77         gr[_REG_PC] = (__greg_t)func;
  78         gr[_REG_nPC] = (__greg_t)func + 4;
  79         gr[_REG_O7] = (__greg_t)_resumecontext - 8;
  80
  81 }