/*
 * Copyright (c) 2003-2005 The Regents of The University of Michigan
 * 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;
 * neither the name of the copyright holders nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT
 * OWNER 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.
 *
 * Authors: Steve Reinhardt
 *          Gabe Black
 */

#ifndef __ARCH_ALPHA_SYSCALLRETURN_HH__
#define __ARCH_ALPHA_SYSCALLRETURN_HH__

class SyscallReturn {
    public:
       template <class T>
       SyscallReturn(T v, bool s)
       {
           retval = (uint64_t)v;
           success = s;
       }

       template <class T>
       SyscallReturn(T v)
       {
           success = (v >= 0);
           retval = (uint64_t)v;
       }

       ~SyscallReturn() {}

       SyscallReturn& operator=(const SyscallReturn& s) {
           retval = s.retval;
           success = s.success;
           return *this;
       }

       bool successful() { return success; }
       uint64_t value() { return retval; }


   private:
       uint64_t retval;
       bool success;
};

namespace AlphaISA
{
    static inline void setSyscallReturn(SyscallReturn return_value, RegFile *regs)
    {
        // check for error condition.  Alpha syscall convention is to
        // indicate success/failure in reg a3 (r19) and put the
        // return value itself in the standard return value reg (v0).
        if (return_value.successful()) {
            // no error
            regs->setIntReg(SyscallSuccessReg, 0);
            regs->setIntReg(ReturnValueReg, return_value.value());
        } else {
            // got an error, return details
            regs->setIntReg(SyscallSuccessReg, (IntReg)-1);
            regs->setIntReg(ReturnValueReg, -return_value.value());
        }
    }
}

#endif
