/*      $NetBSD: contextspfunc.S,v 1.1 2025/04/21 02:33:45 riastradh Exp $      */

/*-
* Copyright (c) 2025 The NetBSD Foundation, Inc.
* All rights reserved.
*
* 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.
*/

#define _LOCORE

#include <machine/asm.h>

RCSID("$NetBSD: contextspfunc.S,v 1.1 2025/04/21 02:33:45 riastradh Exp $")

#ifdef __PIC__
#define SETHI(label, got, reg)                                                \
       set     label, reg;             /* reg := &label - &GOT */            \
       ld      [got + reg], reg        /* reg := &label */
#define LO(label, reg)                                                        \
       reg
#else
#define SETHI(label, got, reg)                                                \
       sethi   %hi(label), reg         /* reg := &label - %lo(label) */
#define LO(label, reg)                                                        \
       reg + %lo(label)
#endif

       .text

/*
* contextspfunc()
*
*      makecontext(3) function.  Store the stack pointer on entry at
*      the global variable contextsp and call contextdone.
*/
ENTRY(contextspfunc)
       /* Reminder: o6 is frame pointer, o7 + 8 is return address. */
       PIC_PROLOGUE(%g1, %o5)                  /* g1 := &GOT, clobber o5 */
       SETHI(_C_LABEL(contextsp), %g1, %o5)    /* o5 := &contextsp */
       call    _C_LABEL(contextdone)           /* jump to contextdone */
        st     %sp, [LO(_C_LABEL(contextsp), %o5)] /* contextsp := sp */
       /* don't care what happens here, caller must never return */
       ta      1                               /* Tcc, trap always */
END(contextspfunc)