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#ifndef ENGINES_DREAMGEN_RUNTIME_H__
#define ENGINES_DREAMGEN_RUNTIME_H__
#include <assert.h>
#include "common/scummsys.h"
#include "common/array.h"
#include "common/hashmap.h"
namespace dreamgen {
//fixme: name clash
#undef random
enum { kLowPartOfRegister = 0, kHighPartOfRegister = 1 };
struct Register {
union {
uint16 _value;
uint8 _part[2];
};
inline Register(): _value() {}
inline Register& operator=(uint16 v) { _value = v; return *this; }
inline operator uint16&() { return _value; }
inline void cbw() {
if (_value & 0x80)
_value |= 0xff00;
else
_value &= 0xff;
}
};
template<unsigned PART>
struct RegisterPart {
uint8 &_part;
inline RegisterPart(Register ®) : _part(reg._part[PART]) {}
inline operator uint8&() {
return _part;
}
inline RegisterPart& operator=(const RegisterPart& o) {
_part = o._part;
return *this;
}
inline RegisterPart& operator=(uint8 v) {
_part = v;
return *this;
}
};
class WordRef {
Common::Array<uint8> &_data;
unsigned _index;
bool _changed;
uint16 _value;
public:
inline WordRef(Common::Array<uint8> &data, unsigned index) : _data(data), _index(index), _changed(false) {
assert(index + 1 < data.size());
_value = _data[index] | (_data[index + 1] << 8);
}
inline WordRef& operator=(const WordRef &ref) {
_changed = true;
_value = ref._value;
return *this;
}
inline WordRef& operator=(uint16 v) {
_changed = true;
_value = v;
return *this;
}
inline operator uint16() const {
return _value;
}
inline operator uint16&() {
return _value;
}
inline ~WordRef() {
if (_changed) {
_data[_index] = _value & 0xff;
_data[_index + 1] = _value >> 8;
}
}
};
struct Segment {
Common::Array<uint8> data;
inline void assign(const uint8 *b, const uint8 *e) {
data.assign(b, e);
}
inline uint8 &byte(unsigned index) {
assert(index < data.size());
return data[index];
}
inline uint16 word(unsigned index) const {
assert(index + 1 < data.size());
return data[index] | (data[index + 1] << 8);
}
inline WordRef word(unsigned index) {
return WordRef(data, index);
}
};
class Context;
class SegmentRef {
Context *_context;
uint16 _value;
Segment *_segment;
public:
SegmentRef(Context *ctx): _context(ctx), _value(), _segment() {
}
inline void reset(uint16 value) {
}
inline SegmentRef& operator=(const uint16 id) {
return *this;
}
inline uint8 &byte(unsigned index) {
assert(_segment != 0);
return _segment->byte(index);
}
inline uint16 word(unsigned index) const {
assert(_segment != 0);
return _segment->word(index);
}
inline operator uint16() const {
return _value;
}
inline WordRef word(unsigned index) {
assert(_segment != 0);
return _segment->word(index);
}
};
struct Flags {
bool _z, _c, _s, _o;
inline Flags(): _z(true), _c(false), _s(false), _o(false) {}
inline bool z() const { return _z; }
inline bool c() const { return _c; }
inline bool s() const { return _s; }
//complex flags:
inline bool g() const { return !_z && _s == _o; }
inline bool ge() const { return _z || _s == _o; }
inline bool l() const { return !_z && _s != _o; }
inline bool le() const { return _z || _s != _o; }
inline void update_sign(uint8 v) {
bool new_s = v & 0x80;
_o = new_s != _s;
_s = new_s;
_z = v == 0;
}
inline void update(uint16 v) {
bool new_s = v & 0x8000;
_o = new_s != _s;
_s = new_s;
_z = v == 0;
}
};
class Context {
Common::HashMap<uint16, Segment> _segments;
public:
Register ax, dx, bx, cx, si, di;
RegisterPart<kLowPartOfRegister> al;
RegisterPart<kHighPartOfRegister> ah;
RegisterPart<kLowPartOfRegister> bl;
RegisterPart<kHighPartOfRegister> bh;
RegisterPart<kLowPartOfRegister> cl;
RegisterPart<kHighPartOfRegister> ch;
RegisterPart<kLowPartOfRegister> dl;
RegisterPart<kHighPartOfRegister> dh;
SegmentRef cs, ds, es;
Flags flags;
inline Context(): al(ax), ah(ax), bl(bx), bh(bx), cl(cx), ch(cx), dl(dx), dh(dx), cs(this), ds(this), es(this) {
}
inline void _cmp(uint8 a, uint8 b) {
uint8 x = a;
_sub(x, b);
}
inline void _cmp(uint16 a, uint16 b) {
uint16 x = a;
_sub(x, b);
}
inline void _test(uint8 a, uint8 b) {
uint8 x = a;
_and(x, b);
}
inline void _test(uint16 a, uint16 b) {
uint16 x = a;
_and(x, b);
}
inline void _add(uint8 &dst, uint8 src) {
flags._c = dst + src < dst;
dst += src;
flags.update(dst);
}
inline void _add(uint16 &dst, uint16 src) {
flags._c = dst + src < dst;
dst += src;
flags.update(dst);
}
inline void _sub(uint8 &dst, uint8 src) {
flags._c = dst < src;
dst -= src;
flags.update(dst);
}
inline void _sub(uint16 &dst, uint16 src) {
flags._c = dst < src;
dst -= src;
flags.update(dst);
}
inline void _and(uint8 &dst, uint8 src) {
dst &= src;
flags._c = false;
flags.update(dst);
}
inline void _and(uint16 &dst, uint16 src) {
dst &= src;
flags._c = false;
flags.update(dst);
}
inline void _or(uint8 &dst, uint8 src) {
dst |= src;
flags._c = false;
flags.update(dst);
}
inline void _or(uint16 &dst, uint16 src) {
dst |= src;
flags._c = false;
flags.update(dst);
}
inline void _xor(uint8 &dst, uint8 src) {
dst ^= src;
flags._c = false;
flags.update(dst);
}
inline void _xor(uint16 &dst, uint16 src) {
dst ^= src;
flags._c = false;
flags.update(dst);
}
inline void _shr(uint8 &dst, uint8 src) {}
inline void _shr(uint16 &dst, uint8 src) {}
inline void _shl(uint8 &dst, uint8 src) {}
inline void _shl(uint16 &dst, uint8 src) {}
inline void _mul(uint8 src) {
unsigned r = unsigned(al) * src;
ax = (uint16)r;
flags._c = r >= 0x10000;
flags._z = r == 0;
bool s = r & 0x8000;
flags._o = s != flags._s;
flags._s = s;
}
inline void _mul(uint16 src) {
unsigned r = unsigned(ax) * src; //assuming here that we have at least 32 bits
dx = (r >> 16) & 0xffff;
ax = r & 0xffff;
flags._c = false;//fixme
flags._z = r == 0;
bool s = r & 0x80000000;
flags._o = s != flags._s;
flags._s = s;
}
inline void _neg(uint8 &src) {
src = ~src;
flags._c = false;
flags.update(src);
}
inline void _neg(uint16 &src) {
src = ~src;
flags._c = false;
flags.update(src);
}
inline void _movsb() {
es.byte(di++) = ds.byte(si++);
}
inline void _movsw() {
es.word(di) = ds.word(si);
di += 2;
si += 2;
}
inline void _lodsb() {
al = ds.byte(si++);
}
inline void _lodsw() {
ax = ds.word(si);
si += 2;
}
inline void _stosb() {
es.byte(di++) = al;
}
inline void _stosw() {
es.word(di) = al;
di += 2;
}
inline void _xchg(uint16 &a, uint16 &b) {
uint16 x = a;
a = b;
b = x;
}
inline void _xchg(uint8 &a, uint8 &b) {
uint8 t = a;
a = b;
b = t;
}
Common::Array<uint16> stack;
inline void push(uint16 v) {
stack.push_back(v);
}
inline uint16 pop() {
uint16 v = stack.back();
stack.pop_back();
return v;
}
Segment data;
};
}
#endif
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