// Copyright (c) 2012-2015, The CryptoNote developers, The Bytecoin developers
//
// This file is part of Bytecoin.
//
// Bytecoin is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Bytecoin is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with Bytecoin.  If not, see <http://www.gnu.org/licenses/>.

#include <string.h>
#include "context.h"

void
makecontext(uctx *ucp, void (*func)(void), intptr_t arg)
{
  long *sp;
  
  memset(&ucp->uc_mcontext, 0, sizeof ucp->uc_mcontext);
  ucp->uc_mcontext.mc_rdi = (long)arg;
  sp = (long*)ucp->uc_stack.ss_sp+ucp->uc_stack.ss_size/sizeof(long);
  sp -= 1;
  sp = (void*)((uintptr_t)sp - (uintptr_t)sp%16);	/* 16-align for OS X */
  *--sp = 0;	/* return address */
  ucp->uc_mcontext.mc_rip = (long)func;
  ucp->uc_mcontext.mc_rsp = (long)sp;
}

int
swapcontext(uctx *oucp, const uctx *ucp)
{
  if(getcontext(oucp) == 0)
    setcontext(ucp);
  return 0;
}