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/*
 * Copyright (C) 2006 Jakub Jermar
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - 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.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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 <libc.h>

/**
 * Immediate operand for break instruction.
 * Be carefull about the value as Ski simulator
 * is somewhat sensitive to its value.
 *
 * 0 will be confused with Ski breakpoint.
 * And higher values will be confused with SSC's.
 */
#define SYSCALL_IMM 1

sysarg_t __syscall(const syscall_t id, const sysarg_t p1, const sysarg_t p2, const sysarg_t p3)
{
    sysarg_t ret;
    
    __asm__ volatile (
        "mov r14 = %1\n"
        "mov r15 = %2\n"
        "mov r16 = %3\n"
        "mov r17 = %4\n"
        "break %5\n"
        "mov %0 = r8\n"
        : "=r" (ret)
        : "r" (id), "r" (p1), "r" (p2), "r" (p3), "i" (SYSCALL_IMM)
        : "r8", "r14", "r15", "r16"
    );
    
    return ret;
}