/*      $NetBSD: elf_support.h,v 1.1 2018/03/29 13:23:39 joerg Exp $    */

/*-
* Copyright (c) 2018 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.
*/
#ifndef _SPARC_ELF_SUPPORT_H
#define _SPARC_ELF_SUPPORT_H

static inline void
sparc_write_branch(void *where_, void *target)
{
       const unsigned int BAA     = 0x30800000U; /* ba,a  (offset / 4) */
       const unsigned int SETHI   = 0x03000000U; /* sethi %hi(0), %g1 */
       const unsigned int JMP     = 0x81c06000U; /* jmpl  %g1+%lo(0), %g0 */

       unsigned int *where = (unsigned int *)where_;
       unsigned long value = (unsigned long)target;
       unsigned long offset = value - (unsigned long)where;

#define HIVAL(v, s)     (((v) >> (s)) & 0x003fffffU)
#define LOVAL(v, s)     (((v) >> (s)) & 0x000003ffU)
       if (offset + 0x800000 <= 0x7ffffc) {
               /* Displacement is within 8MB, use a direct branch. */
               where[0] = BAA | ((offset >> 2) & 0x3fffff);
               __asm volatile("iflush %0+0" : : "r" (where));
               return;
       }

       /*
        * The absolute address is a 32bit value.
        * This can be encoded as:
        *      sethi   %hi(value), %g1
        *      jmp     %g1+%lo(value)
        */
       where[1] = JMP   | LOVAL(value, 0);
       __asm volatile("iflush %0+4" : : "r" (where));
       where[0] = SETHI | HIVAL(value, 10);
       __asm volatile("iflush %0+0" : : "r" (where));
#undef  HIVAL
#undef  LOVAL
}
#endif