vm_types.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.
 *
 * 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 SCI_ENGINE_VM_TYPES_H
#define SCI_ENGINE_VM_TYPES_H

#include "common/scummsys.h"
#include "sci/version.h"

namespace Sci {

// Segment ID type
typedef uint16 SegmentId;

enum {
    kUninitializedSegment = 0x1FFF,
    kSegmentMask = 0x1FFF,
    kOffsetMask = 0x7FFFF
};

struct reg_t {
    // Segment and offset. These should never be accessed directly
    SegmentId _segment;
    uint16 _offset;

    void init(SegmentId segment, uint32 offset);

    SegmentId getSegment() const;
    void setSegment(SegmentId segment);

    // speed optimization: inline due to frequent calling
    uint32 getOffset() const {
        if (getSciVersion() < SCI_VERSION_3) {
            return _offset;
        } else {
            // Return the lower 16 bits from the offset, and the 17th and 18th bits from the segment
            return ((_segment & 0xC000) << 2) | _offset;
        }
    }

    // speed optimization: inline due to frequent calling
    void setOffset(uint32 offset) {
        if (getSciVersion() < SCI_VERSION_3) {
            _offset = offset;
        } else {
            // Store the lower 16 bits in the offset, and the 17th and 18th bits in the segment
            _offset = offset & 0xFFFF;
            _segment = ((offset & 0x30000) >> 2) | (_segment & 0x3FFF);
        }
    }

    inline void incOffset(int32 offset) {
        setOffset(getOffset() + offset);
    }

    inline bool isNull() const {
        return (getOffset() | getSegment()) == 0;
    }

    inline uint16 toUint16() const {
        return (uint16)getOffset();
    }

    inline int16 toSint16() const {
        return (int16)getOffset();
    }

    bool isNumber() const {
        return getSegment() == 0;
    }

    bool isPointer() const {
        return getSegment() != 0 && getSegment() != kUninitializedSegment;
    }

    uint16 requireUint16() const;
    int16 requireSint16() const;

    inline bool isInitialized() const {
        return getSegment() != kUninitializedSegment;
    }

    // Comparison operators
    bool operator==(const reg_t &x) const {
        return (getOffset() == x.getOffset()) && (getSegment() == x.getSegment());
    }

    bool operator!=(const reg_t &x) const {
        return (getOffset() != x.getOffset()) || (getSegment() != x.getSegment());
    }

    bool operator>(const reg_t right) const {
        return cmp(right, false) > 0;
    }

    bool operator>=(const reg_t right) const {
        return cmp(right, false) >= 0;
    }

    bool operator<(const reg_t right) const {
        return cmp(right, false) < 0;
    }

    bool operator<=(const reg_t right) const {
        return cmp(right, false) <= 0;
    }

    // Same as the normal operators, but perform unsigned
    // integer checking
    bool gtU(const reg_t right) const {
        return cmp(right, true) > 0;
    }

    bool geU(const reg_t right) const {
        return cmp(right, true) >= 0;
    }

    bool ltU(const reg_t right) const {
        return cmp(right, true) < 0;
    }

    bool leU(const reg_t right) const {
        return cmp(right, true) <= 0;
    }

    // Arithmetic operators
    reg_t operator+(const reg_t right) const;
    reg_t operator-(const reg_t right) const;
    reg_t operator*(const reg_t right) const;
    reg_t operator/(const reg_t right) const;
    reg_t operator%(const reg_t right) const;
    reg_t operator>>(const reg_t right) const;
    reg_t operator<<(const reg_t right) const;

    reg_t operator+(int16 right) const;
    reg_t operator-(int16 right) const;

    void operator+=(const reg_t &right) { *this = *this + right; }
    void operator-=(const reg_t &right) { *this = *this - right; }
    void operator+=(int16 right) { *this = *this + right; }
    void operator-=(int16 right) { *this = *this - right; }

    // Boolean operators
    reg_t operator&(const reg_t right) const;
    reg_t operator|(const reg_t right) const;
    reg_t operator^(const reg_t right) const;

#ifdef ENABLE_SCI32
    reg_t operator&(int16 right) const;
    reg_t operator|(int16 right) const;
    reg_t operator^(int16 right) const;

    void operator&=(const reg_t &right) { *this = *this & right; }
    void operator|=(const reg_t &right) { *this = *this | right; }
    void operator^=(const reg_t &right) { *this = *this ^ right; }
    void operator&=(int16 right) { *this = *this & right; }
    void operator|=(int16 right) { *this = *this | right; }
    void operator^=(int16 right) { *this = *this ^ right; }
#endif

private:
    int cmp(const reg_t right, bool treatAsUnsigned) const;
    reg_t lookForWorkaround(const reg_t right, const char *operation) const;
    bool pointerComparisonWithInteger(const reg_t right) const;

#ifdef ENABLE_SCI32
    int sci32Comparison(const reg_t right) const;
#endif
};

static inline reg_t make_reg(SegmentId segment, uint16 offset) {
    reg_t r;
    r.init(segment, offset);
    return r;
}

static inline reg_t make_reg32(SegmentId segment, uint32 offset) {
    reg_t r;
    r.init(segment, offset);
    return r;
}

#define PRINT_REG(r) (kSegmentMask) & (unsigned) (r).getSegment(), (unsigned) (r).getOffset()

// Stack pointer type
typedef reg_t *StackPtr;

enum {
    SIGNAL_OFFSET = 0xffff
};

extern const reg_t NULL_REG;
extern const reg_t SIGNAL_REG;
extern const reg_t TRUE_REG;

// Selector ID
typedef int Selector;

enum {
    NULL_SELECTOR = -1
};

// Opcode formats
enum opcode_format {
    Script_Invalid = -1,
    Script_None = 0,
    Script_Byte,
    Script_SByte,
    Script_Word,
    Script_SWord,
    Script_Variable,
    Script_SVariable,
    Script_SRelative,
    Script_Property,
    Script_Global,
    Script_Local,
    Script_Temp,
    Script_Param,
    Script_Offset,
    Script_End
};


} // End of namespace Sci

#endif // SCI_ENGINE_VM_TYPES_H