opcode.c

开发源代码的CPU卡的COS源程序。

/* ============================================================================
   Project Name : jayaCard
   Module Name  : proto/bios/patch/opcode.c
   Version : $Id: opcode.c,v 1.12 2004/01/11 09:56:31 dgil Exp $

	Description: opcode management

    The Original Code is jayaCard code.

    The Initial Developer of the Original Code is Gilles Dumortier.

	Portions created by the Initial Developer are Copyright (C) 2002-2004 the
    Initial Developer. All Rights Reserved.

    Contributor(s):

    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 of the License, 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; see http://www.gnu.org/licenses/gpl.html

	History Rev	Description
   012603 dgil	wrote it from scratch - today we have an entry point !
   ============================================================================
*/

#include "precomp.h"

/* ============================================================================
	Given the opcode number OPCODE_x, tab_opcode_ind[OPCODE_x] -> executable
 	code address ADDR_OPCODE_x in EEPROM
   ========================================================================= */

extern jword code tab_opcode_ind[NUM_OPCODES];

/* ============================================================================
	__bios_call_opcode()

	Given the opcode number, check the opcode and jump to only if it is a
	valid executable address.

	Return
		JSEC_FAIL	invalid opcode or opcode can't do the work
		JSEC_OK		valid opcode then opcode have done the work
   ========================================================================= */

struct {
	jword	aexec;
	jword	crc;
} xdata exec;

jbyte __bios_call_opcode(jbyte nexec)
{
	/* check opcode number */
	if (nexec>sizeof(tab_opcode_ind)/sizeof(tab_opcode_ind[0])) {
		LOG1("ATTACK","__bios_call_opcode() opcode=%d invalid !",nexec);
		HAL_HALT();
		return JSEC_FAIL;
	}

	/* read address of opcode from memory */
	HAL_EEPROM_READ((jbyte xdata*)&exec,tab_opcode_ind[nexec],4);
	HAL_CRC_INIT();
	HAL_CRC_COMPUTE(HIBYTE(exec.aexec));
	HAL_CRC_COMPUTE(LOBYTE(exec.aexec));
	if ( (HAL_CRC_LO()!=LOBYTE(exec.crc)) || (HAL_CRC_HI()!=HIBYTE(exec.crc)) ) {
		/* no optional code */
		return JSEC_FAIL;
	}

	/* optional code / jump to */
	return HAL_CALL(exec.aexec);
}

/* =========================================================================
	That's all folks !
   ========================================================================= */