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get negative offsets right

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This commit is contained in:
Stephen Crane 2016-01-21 06:32:44 +00:00
parent ed268ed430
commit 8c24019f1f
2 changed files with 30 additions and 20 deletions
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2
z80.cpp
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@ -64,7 +64,7 @@ byte z80::_fetch_op() {
_mc(PC, 4);
byte op = _mem[PC];
#if defined(CPU_DEBUG)
printf("%5d MR %04x %02x\n", _ts, PC, op);
_status("%5d MR %04x %02x\n", _ts, PC, op);
#endif
PC++;
R++;

48
z80.h
View File

@ -312,12 +312,18 @@ private:
flags.N = 1;
}
inline word _ads(word a, byte b) {
word w = a + b;
if (b > 127) w -= 0x100;
return w;
}
inline void _incO(Memory::address a) {
char o = (char)_rb(PC);
byte o = _rb(PC);
_mc(PC, 1); _mc(PC, 1); _mc(PC, 1);
_mc(PC, 1); _mc(PC, 1);
PC++;
word w = a + o;
word w = _ads(a, o);
byte b = _rb(w);
_mc(w, 1);
_inc(b);
@ -325,11 +331,11 @@ private:
}
inline void _decO(Memory::address a) {
char o = (char)_rb(PC);
byte o = _rb(PC);
_mc(PC, 1); _mc(PC, 1); _mc(PC, 1);
_mc(PC, 1); _mc(PC, 1);
PC++;
word w = a + o;
word w = _ads(a, o);
byte b = _rb(w);
_mc(w, 1);
_dec(b);
@ -337,27 +343,27 @@ private:
}
inline void _sbO(Memory::address a) {
char o = (char)_rb(PC++);
byte o = _rb(PC++);
byte b = _rb(PC);
_mc(PC, 1); _mc(PC, 1);
PC++;
_sb(a + o, b);
_sb(_ads(a, o), b);
}
inline byte _rbO(Memory::address a) {
char o = (char)_rb(PC);
byte o = _rb(PC);
_mc(PC, 1); _mc(PC, 1); _mc(PC, 1);
_mc(PC, 1); _mc(PC, 1);
PC++;
return _rb(a + o);
return _rb(_ads(a, o));
}
inline void _sbO(Memory::address a, byte b) {
char o = (char)_rb(PC);
byte o = _rb(PC);
_mc(PC, 1); _mc(PC, 1); _mc(PC, 1);
_mc(PC, 1); _mc(PC, 1);
PC++;
_sb(a + o, b);
_sb(_ads(a, o), b);
}
inline void _exSP(word &reg) {
@ -417,7 +423,11 @@ private:
}
// 0x18
void jr() { char o = (char)_rb(PC); _mc(PC, 1); _mc(PC, 1); _mc(PC, 1); _mc(PC, 1); _mc(PC, 1); PC += o + 1; }
void jr() {
byte b = _rb(PC);
_mc(PC, 1); _mc(PC, 1); _mc(PC, 1); _mc(PC, 1); _mc(PC, 1);
PC = _ads(PC, b+1);
}
void addhlde() { _add16(HL, DE); }
void ldaDE() { A = _rb(DE); }
void decde() { DE--; _mc(IR, 1); _mc(IR, 1); }
@ -1163,7 +1173,7 @@ private:
// 0xDDCB extended instructions
inline word _rbIX(byte &b, byte o) {
word a = IX + (char)o;
word a = _ads(IX, o);
b = _rb(a);
_mc(a, 1);
return a;
@ -1274,7 +1284,7 @@ private:
void srlIXA(byte o) { _srlIX(A, o); }
// 0x40
inline void _bitIX(int i, byte o) { _bitI(i, IX + (char)o); }
inline void _bitIX(int i, byte o) { _bitI(i, _ads(IX, o)); }
void bit0IX(byte o) { _bitIX(0, o); }
@ -1301,7 +1311,7 @@ private:
// 0x80
void _resIX(byte &b, byte o, byte m) {
word a = IX + (char)o;
word a = _ads(IX, o);
b = _rb(a) & m;
_mc(a, 1);
_sb(a, b);
@ -1387,7 +1397,7 @@ private:
// 0xc0
void _setIX(byte &b, byte o, byte m) {
word a = IX + (char)o;
word a = _ads(IX, o);
b = _rb(a) | m;
_mc(a, 1);
_sb(a, b);
@ -1474,7 +1484,7 @@ private:
// 0xFDCB extended instructions
inline word _rbIY(byte &b, byte o) {
word a = IY + (char)o;
word a = _ads(IY, o);
b = _rb(a);
_mc(a, 1);
return a;
@ -1585,7 +1595,7 @@ private:
void srlIYA(byte o) { _srlIY(A, o); }
// 0x40
inline void _bitIY(int i, byte o) { _bitI(i, IY + (char)o); }
inline void _bitIY(int i, byte o) { _bitI(i, _ads(IY, o)); }
void bit0IY(byte o) { _bitIY(0, o); }
@ -1612,7 +1622,7 @@ private:
// 0x80
void _resIY(byte &b, byte o, byte m) {
word a = IY + (char)o;
word a = _ads(IY, o);
b = _rb(a) & m;
_mc(a, 1);
_sb(a, b);
@ -1698,7 +1708,7 @@ private:
// 0xc0
void _setIY(byte &b, byte o, byte m) {
word a = IY + (char)o;
word a = _ads(IY, o);
b = _rb(a) | m;
_mc(a, 1);
_sb(a, b);