/* src/vm/jit/mips/md.h - machine dependent MIPS functions

   Copyright (C) 1996-2005, 2006, 2007, 2008
   CACAOVM - Verein zur Foerderung der freien virtuellen Maschine CACAO

   This file is part of CACAO.

   This program is free software; you can redistribute it and/or
   modify it under the terms of the GNU General Public License as
   published by the Free Software Foundation; either version 2, or (at
   your option) any later version.

   This program 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
   General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
   02110-1301, USA.

*/


#ifndef _VM_JIT_MIPS_MD_H
#define _VM_JIT_MIPS_MD_H

#include "config.h"

#include <assert.h>
#include <stdint.h>
#include <unistd.h>
#include <sys/cachectl.h>

#include "vm/types.h"

#include "vm/vm.hpp"


/* md_stacktrace_get_returnaddress *********************************************

   Returns the return address of the current stackframe, specified by
   the passed stack pointer and the stack frame size.

*******************************************************************************/

inline static void *md_stacktrace_get_returnaddress(void *sp, int32_t stackframesize)
{
	void *ra;

	/* On MIPS the return address is located on the top of the
	   stackframe. */

	ra = *((void **) (((uintptr_t) sp) + stackframesize - 8));

	return ra;
}


/* md_codegen_get_pv_from_pc ***************************************************

   Machine code:

   03c0f809    jalr     s8
   00000000    nop
   27feff9c    addiu    s8,ra,-100

*******************************************************************************/

inline static void* md_codegen_get_pv_from_pc(void* ra)
{
	int32_t offset;

	uint32_t* pc = (uint32_t*) ra;

	/* get the offset of the instructions */

	/* get first instruction word after jump */

	uint32_t mcode = pc[0];

	/* check if we have 2 instructions (lui, daddiu) */

	if ((mcode >> 16) == 0x3c19) {
		/* get displacement of first instruction (lui) */

		offset = (int32_t) (mcode << 16);

		/* get displacement of second instruction (daddiu) */

		mcode = pc[1];

#if SIZEOF_VOID_P == 8
		assert((mcode >> 16) == 0x6739);
#else
		assert((mcode >> 16) == 0x2739);
#endif

		offset += (int16_t) (mcode & 0x0000ffff);
	}
	else {
		/* get offset of first instruction (daddiu) */

#if SIZEOF_VOID_P == 8
		assert((mcode >> 16) == 0x67fe);
#else
		assert((mcode >> 16) == 0x27fe);
#endif

		offset = (int16_t) (mcode & 0x0000ffff);
	}

	/* calculate PV via RA + offset */

	void* pv = (void*) (((uintptr_t) ra) + offset);

	return pv;
}


/* md_cacheflush ***************************************************************

   Calls the system's function to flush the instruction and data
   cache.

*******************************************************************************/

inline static void md_cacheflush(void *addr, int nbytes)
{
	cacheflush(addr, nbytes, BCACHE);
}


/* md_icacheflush **************************************************************

   Calls the system's function to flush the instruction cache.

*******************************************************************************/

inline static void md_icacheflush(void *addr, int nbytes)
{
	cacheflush(addr, nbytes, ICACHE);
}


/* md_dcacheflush **************************************************************

   Calls the system's function to flush the data cache.

*******************************************************************************/

inline static void md_dcacheflush(void *addr, int nbytes)
{
	cacheflush(addr, nbytes, DCACHE);
}

#endif /* _VM_JIT_MIPS_MD_H */


/*
 * These are local overrides for various environment variables in Emacs.
 * Please do not remove this and leave it at the end of the file, where
 * Emacs will automagically detect them.
 * ---------------------------------------------------------------------
 * Local variables:
 * mode: c
 * indent-tabs-mode: t
 * c-basic-offset: 4
 * tab-width: 4
 * End:
 * vim:noexpandtab:sw=4:ts=4:
 */