/* src/vm/jit/sparc64/md.c - machine dependent SPARC64 functions

   Copyright (C) 1996-2005, 2006, 2007 R. Grafl, A. Krall, C. Kruegel,
   C. Oates, R. Obermaisser, M. Platter, M. Probst, S. Ring,
   E. Steiner, C. Thalinger, D. Thuernbeck, P. Tomsich, C. Ullrich,
   J. Wenninger, Institut f. Computersprachen - TU Wien

   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_SPARC64_MD_H
#define _VM_JIT_SPARC64_MD_H

#include "config.h"

#include <assert.h>
#include <stdint.h>

#include "vm/types.h"

#include "vm/jit/codegen-common.hpp"


/**
 * Returns the size (in bytes) of the current stackframe, specified by
 * the passed codeinfo structure.
 */
inline static int32_t md_stacktrace_get_framesize(codeinfo* code)
{
	// Check for the asm_vm_call_method special case.
	if (code == NULL)
		return 0;

	// On SPARC we use 8-byte stackslots.
#error Verify the below line, then remove this error!
	return code->stackframesize * 8;
}


/* 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;

	/* flush register windows to the stack */
	__asm__ ("flushw");

	/* the return address resides in register i7, the last register in the
	 * 16-extended-word save area
	 */
	ra = *((void **) (((uintptr_t) sp) + 120 + BIAS));
	
	/* NOTE: on SPARC ra is the address of the call instruction */

	return ra;
}

inline static void *md_get_framepointer(void *sp)
{
	void *fp;

	/* flush register windows to the stack */
	__asm__ ("flushw");

	fp = *((void **) (((uintptr_t) sp) + 112 + BIAS));

	return fp;
}

inline static void *md_get_pv_from_stackframe(void *sp)
{
	void *pv;

	/* flush register windows to the stack */
	__asm__ ("flushw");

	pv = *((void **) (((uintptr_t) sp) + 104 + BIAS));

	return pv;
}


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

   This reconstructs and returns the PV of a method given a return address
   pointer. (basically, same was as the generated code following the jump does)
   
   Machine code:

   6b5b4000    jmpl    (pv)
   10000000    nop
   277afffe    ldah    pv,-2(ra)
   237ba61c    lda     pv,-23012(pv)

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

/* TODO Move these macros into the code generator. */

/* shift away 13-bit immediate,  mask rd and rs1    */
#define SHIFT_AND_MASK(instr) \
	((instr >> 13) & 0x60fc1)

/* NOP is defined as a SETHI instruction with rd and imm. set to zero */
/* therefore we check if the 22-bit immediate is zero */
#define IS_SETHI(instr) \
	(((instr & 0xc1c00000)  == 0x01000000) \
	&& ((instr & 0x3fffff) != 0x0))

inline s2 decode_13bit_imm(u4 instr) {
	s2 imm;

	/* mask everything else in the instruction */
	imm = instr & 0x00001fff;

	/* sign extend 13-bit to 16-bit */
	imm <<= 3;
	imm >>= 3;

	return imm;
}

inline static void *md_codegen_get_pv_from_pc(void *ra)
{
	uint8_t *pv;
	u8  mcode;
	s4  offset;

	pv = ra;

	/* get the instruction word after jump and nop */
	mcode = *((u4 *) (ra+8) );

	/* check if we have a sethi insruction */
	if (IS_SETHI(mcode)) {
		s4 xor_imm;
				
		/* get 22-bit immediate of sethi instruction */
		offset = (s4) (mcode & 0x3fffff);
		offset = offset << 10;
		
		/* now the xor */
		mcode = *((u4 *) (ra+12) );
		xor_imm = decode_13bit_imm(mcode);
		
		offset ^= xor_imm;	 
	}
	else {
		u4 mcode_masked;
		
		mcode_masked = SHIFT_AND_MASK(mcode);

		assert(mcode_masked == 0x40001);

		/* mask and extend the negative sign for the 13 bit immediate */
		offset = decode_13bit_imm(mcode);
	}
	
	pv += 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)
{
	/* don't know yet */	
}


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

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

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

inline static void md_dcacheflush(void *addr, int nbytes)
{
	/* XXX don't know yet */	
	/* printf("md_dcacheflush\n"); */
	__asm__ __volatile__ ( "membar 0x7F" : : : "memory" );
}

#endif /* _VM_JIT_SPARC64_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:
 */
