/* src/vm/jit/alpha/md.c - machine dependent Alpha 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.

*/


#include "config.h"

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

#if defined(__LINUX__)
# include <asm/fpu.h>

extern unsigned long ieee_get_fp_control();
extern void ieee_set_fp_control(unsigned long fp_control);
#endif

#include "vm/jit/alpha/codegen.h"
#include "vm/jit/alpha/md.h"

#include "vm/exceptions.h"

#include "vm/jit/asmpart.h"
#include "vm/jit/jit.h"


/* global variables ***********************************************************/

bool has_ext_instr_set = false;             /* has instruction set extensions */


/* md_init *********************************************************************

   Do some machine dependent initialization.

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

void md_init(void)
{
#if defined(__LINUX__)
	unsigned long int fpcw;
#endif

	/* check for extended instruction set */

	has_ext_instr_set = !asm_md_init();

#if defined(__LINUX__)
	/* Linux on Digital Alpha needs an initialisation of the ieee
	   floating point control for IEEE compliant arithmetic (option
	   -mieee of GCC). Under Digital Unix this is done
	   automatically. */

	/* initialize floating point control */

	fpcw = ieee_get_fp_control();

	fpcw = fpcw
		& ~IEEE_TRAP_ENABLE_INV
		& ~IEEE_TRAP_ENABLE_DZE
		/* We dont want underflow. */
/* 		& ~IEEE_TRAP_ENABLE_UNF */
		& ~IEEE_TRAP_ENABLE_OVF;

/* 	fpcw = fpcw */
/* 		| IEEE_TRAP_ENABLE_INV */
/* 		| IEEE_TRAP_ENABLE_DZE */
/* 		| IEEE_TRAP_ENABLE_OVF */
/* 		| IEEE_TRAP_ENABLE_UNF */
/* 		| IEEE_TRAP_ENABLE_INE */
/* 		| IEEE_TRAP_ENABLE_DNO; */

	ieee_set_fp_control(fpcw);
#endif
}


/* md_jit_method_patch_address *************************************************

   Gets the patch address of the currently compiled method. The offset
   is extracted from the load instruction(s) before the jump and added
   to the right base address (PV or REG_METHODPTR).

   INVOKESTATIC/SPECIAL:

   a77bffb8    ldq     pv,-72(pv)
   6b5b4000    jsr     (pv)

   INVOKEVIRTUAL:

   a7900000    ldq     at,0(a0)
   a77c0000    ldq     pv,0(at)
   6b5b4000    jsr     (pv)

   INVOKEINTERFACE:

   a7900000    ldq     at,0(a0)
   a79cff98    ldq     at,-104(at)
   a77c0018    ldq     pv,24(at)
   6b5b4000    jsr     (pv)

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

void *md_jit_method_patch_address(void *pv, void *ra, void *mptr)
{
	uint32_t *pc;
	uint32_t  mcode;
	int       opcode;
	int       base;
	int32_t   disp;
	void     *pa;                       /* patch address                      */

	/* Go back to the load instruction (2 instructions). */

	pc = ((uint32_t *) ra) - 2;

	/* Get first instruction word. */

	mcode = pc[0];

	/* Get opcode, base register and displacement. */

	opcode = M_MEM_GET_Opcode(mcode);
	base   = M_MEM_GET_Rb(mcode);
	disp   = M_MEM_GET_Memory_disp(mcode);

	/* Check for short or long load (2 instructions). */

	switch (opcode) {
	case 0x29: /* LDQ: TODO use define */
		switch (base) {
		case REG_PV:
			/* Calculate the data segment address. */

			pa = ((uint8_t *) pv) + disp;
			break;

		case REG_METHODPTR:
			/* Return NULL if no mptr was specified (used for
			   replacement). */

			if (mptr == NULL)
				return NULL;

			/* Calculate the address in the vftbl. */

			pa = ((uint8_t *) mptr) + disp;
			break;

		default:
			vm_abort_disassemble(pc, 2, "md_jit_method_patch_address: unknown instruction %x", mcode);
			return NULL;
		}
		break;

	case 0x09: /* LDAH: TODO use define */
		/* XXX write a regression for this */

		vm_abort("md_jit_method_patch_address: IMPLEMENT ME!");

		pa = NULL;
		break;

	default:
		vm_abort_disassemble(pc, 2, "md_jit_method_patch_address: unknown instruction %x", mcode);
		return NULL;
	}

	return pa;
}


/* md_patch_replacement_point **************************************************

   Patch the given replacement point.

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

#if defined(ENABLE_REPLACEMENT)
void md_patch_replacement_point(u1 *pc, u1 *savedmcode, bool revert)
{
	u4 mcode;

	if (revert) {
		/* restore the patched-over instruction */
		*(u4*)(pc) = *(u4*)(savedmcode);
	}
	else {
		/* save the current machine code */
		*(u4*)(savedmcode) = *(u4*)(pc);

		/* build the machine code for the patch */
		mcode = (0xa41f0000 | (EXCEPTION_HARDWARE_PATCHER));

		/* write the new machine code */
		*(u4*)(pc) = mcode;
	}
	
	/* flush instruction cache */
    md_icacheflush(pc,4);
}
#endif /* defined(ENABLE_REPLACEMENT) */


/*
 * 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:
 */