/* Create new context.  RISC-V version.

   Copyright (C) 2001-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   The GNU C Library 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 2.1 of the License, or (at your option) any later version.

   The GNU C Library 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 the GNU C Library.  If not, see

   <http://www.gnu.org/licenses/>.  */

#include <sysdep.h>

#include <sys/asm.h>

#include <sys/ucontext.h>

#include <stdarg.h>

#include <assert.h>

void

__makecontext (ucontext_t *ucp, void (*func) (void), int argc,

	       long int a0, long int a1, long int a2, long int a3, long int a4,

	       ...)

{

  extern void __start_context (void) attribute_hidden;

  long int i, sp;

  _Static_assert (REG_NARGS == 8, "__makecontext assumes 8 argument registers");

  /* Set up the stack.  */

  sp = ((long int) ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size) & ALMASK;

  /* Set up the register context.

     ra = s0 = 0, terminating the stack for backtracing purposes.

     s1 = the function we must call.

     s2 = the subsequent context to run.  */

  ucp->uc_mcontext.__gregs[REG_RA] = 0;

  ucp->uc_mcontext.__gregs[REG_S0] = 0;

  ucp->uc_mcontext.__gregs[REG_S1] = (long int) func;

  ucp->uc_mcontext.__gregs[REG_S2] = (long int) ucp->uc_link;

  ucp->uc_mcontext.__gregs[REG_SP] = sp;

  ucp->uc_mcontext.__gregs[REG_PC] = (long int) &__start_context;

  /* Put args in a0-a7, then put any remaining args on the stack.  */

  ucp->uc_mcontext.__gregs[REG_A0 + 0] = a0;

  ucp->uc_mcontext.__gregs[REG_A0 + 1] = a1;

  ucp->uc_mcontext.__gregs[REG_A0 + 2] = a2;

  ucp->uc_mcontext.__gregs[REG_A0 + 3] = a3;

  ucp->uc_mcontext.__gregs[REG_A0 + 4] = a4;

  if (__glibc_unlikely (argc > 5))

    {

      va_list vl;

      va_start (vl, a4);

      long reg_args = argc < REG_NARGS ? argc : REG_NARGS;

      for (i = 5; i < reg_args; i++)

        ucp->uc_mcontext.__gregs[REG_A0 + i] = va_arg (vl, long);

      long int stack_args = argc - reg_args;

      if (stack_args > 0)

	{

	  sp = (sp - stack_args * sizeof (long int)) & ALMASK;

	  ucp->uc_mcontext.__gregs[REG_SP] = sp;

	  for (i = 0; i < stack_args; i++)

	    ((long int *) sp)[i] = va_arg (vl, long int);

	}

      va_end (vl);

    }

}

weak_alias (__makecontext, makecontext)