interpreter.h

/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * Additional copyright for this file:
 * Copyright (C) 1994-1998 Revolution Software Ltd.
 *
 * 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 3 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.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef SWORD2_INTERPRETER_H
#define SWORD2_INTERPRETER_H

#include "common/endian.h"

namespace Sword2 {

// Interpreter return codes

enum {
    IR_STOP     = 0,    // Quit for a cycle
    IR_CONT     = 1,    // Continue as normal
    IR_TERMINATE    = 2,    // Return without updating the offset
    IR_REPEAT   = 3,    // Return; offset at start of function call
    IR_GOSUB    = 4 // Return with updated offset
};

// Get parameter fix so that the playstation version can handle words not on
// word boundaries

#define Read8ip(var)        { var = code[ip]; ip++; }
#define Read16ip(var)       { var = (int16)READ_LE_UINT16(code + ip); ip += 2; }
#define Read32ip(var)       { var = (int32)READ_LE_UINT32(code + ip); ip += 4; }
#define Read32ipLeaveip(var)    { var = (int32)READ_LE_UINT32(code + ip); }

enum {
    // Compiled tokens

    CP_END_SCRIPT           = 0,
    CP_PUSH_LOCAL_VAR32     = 1,    // Push a local variable on to the stack
    CP_PUSH_GLOBAL_VAR32        = 2,    // Push a global variable
    CP_POP_LOCAL_VAR32      = 3,    // Pop a local variable from the stack
    CP_CALL_MCODE           = 4,    // Call a machine code function
    CP_PUSH_LOCAL_ADDR      = 5,    // Push the address of a local variable
    CP_PUSH_INT32           = 6,    // Adjust the stack after calling an fn function
    CP_SKIPONFALSE          = 7,    // Skip if the bottom value on the stack is false
    CP_SKIPALWAYS           = 8,    // Skip a block of code
    CP_SWITCH           = 9,    // Switch on last stack value
    CP_ADDNPOP_LOCAL_VAR32      = 10,   // Add to a local varible
    CP_SUBNPOP_LOCAL_VAR32      = 11,   // Subtract from a local variable
    CP_SKIPONTRUE           = 12,   // Skip if the bottom value on the stack is true
    CP_POP_GLOBAL_VAR32     = 13,   // Pop a global variable
    CP_ADDNPOP_GLOBAL_VAR32     = 14,   // Add to a global variable
    CP_SUBNPOP_GLOBAL_VAR32     = 15,   // Subtract from a global variable
    CP_DEBUGON          = 16,   // Turn debugging on
    CP_DEBUGOFF         = 17,   // Turn debugging off
    CP_QUIT             = 18,   // Quit for a cycle
    CP_TERMINATE            = 19,   // Quit script completely

    // Operators

    OP_ISEQUAL          = 20,   // '=='
    OP_PLUS             = 21,   // '+'
    OP_MINUS            = 22,   // '-'
    OP_TIMES            = 23,   // '*'
    OP_DIVIDE           = 24,   // '/'
    OP_NOTEQUAL         = 25,   // '=='
    OP_ANDAND           = 26,   // '&&'
    OP_GTTHAN           = 27,   // '>'
    OP_LSTHAN           = 28,   // '<'

    // More tokens, mixed types

    CP_JUMP_ON_RETURNED     = 29,   // Use table of jumps with value returned from fn_mcode
    CP_TEMP_TEXT_PROCESS        = 30,   // A dummy text process command for me
    CP_SAVE_MCODE_START     = 31,   // Save the mcode code start for restarting when necessary
    CP_RESTART_SCRIPT       = 32,   // Start the script from the beginning
    CP_PUSH_STRING          = 33,   // Push a pointer to a string on the stack
    CP_PUSH_DEREFERENCED_STRUCTURE  = 34,   // Push the address of a structure thing
    OP_GTTHANE          = 35,   // >=
    OP_LSTHANE          = 36,   // <=
    OP_OROR             = 37    // || or OR
};

} // End of namespace Sword2

#endif