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68000: implement NEG, fix bug on ANDI.L

This commit is contained in:
beirich 2011-10-09 06:19:59 +00:00
parent a1d8e9a209
commit 2d2bfae611
4 changed files with 86 additions and 1 deletions
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1
BizHawk.Emulation/CPUs/68000/Diassembler.cs
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@ -48,6 +48,7 @@ namespace BizHawk.Emulation.CPUs.M68000
else if (Opcodes[op] == OR0) OR0_Disasm(info);
else if (Opcodes[op] == OR1) OR1_Disasm(info);
else if (Opcodes[op] == NOT) NOT_Disasm(info);
else if (Opcodes[op] == NEG) NEG_Disasm(info);
else if (Opcodes[op] == JMP) JMP_Disasm(info);
else if (Opcodes[op] == JSR) JSR_Disasm(info);

2
BizHawk.Emulation/CPUs/68000/Instructions/BitArithemetic.cs
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@ -175,7 +175,7 @@ namespace BizHawk.Emulation.CPUs.M68000
}
case 2: // Long
{
int imm = ReadLong(PC); PC += 2;
int imm = ReadLong(PC); PC += 4;
int arg = PeekValueL(dstMode, dstReg);
int result = imm & arg;
WriteValueL(dstMode, dstReg, result);

83
BizHawk.Emulation/CPUs/68000/Instructions/IntegerMath.cs
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@ -650,6 +650,89 @@ namespace BizHawk.Emulation.CPUs.M68000
info.Length = pc - info.PC;
}
void NEG()
{
int size = (op >> 6) & 0x03;
int mode = (op >> 3) & 0x07;
int reg = op & 0x07;
if (mode == 1) throw new Exception("NEG on address reg is invalid");
switch (size)
{
case 0: // Byte
{
sbyte value = PeekValueB(mode, reg);
int result = 0 - value;
int uresult = 0 - (byte)value;
N = (result & 0x80) != 0;
Z = result == 0;
V = result > sbyte.MaxValue || result < sbyte.MinValue;
C = X = (uresult & 0x100) != 0;
WriteValueB(mode, reg, (sbyte)result);
if (mode == 0) PendingCycles -= 4;
else PendingCycles -= 8 + EACyclesBW[mode, reg];
return;
}
case 1: // Word
{
short value = PeekValueW(mode, reg);
int result = 0 - value;
int uresult = 0 - (ushort)value;
N = (result & 0x8000) != 0;
Z = result == 0;
V = result > short.MaxValue || result < short.MinValue;
C = X = (uresult & 0x10000) != 0;
WriteValueW(mode, reg, (short)result);
if (mode == 0) PendingCycles -= 4;
else PendingCycles -= 8 + EACyclesBW[mode, reg];
return;
}
case 2: // Long
{
int value = PeekValueL(mode, reg);
long result = 0 - value;
long uresult = 0 - (uint)value;
N = (result & 0x80000000) != 0;
Z = result == 0;
V = result > int.MaxValue || result < int.MinValue;
C = X = (uresult & 0x100000000) != 0;
WriteValueL(mode, reg, (int)result);
if (mode == 0) PendingCycles -= 8;
else PendingCycles -= 12 + EACyclesL[mode, reg];
return;
}
}
}
void NEG_Disasm(DisassemblyInfo info)
{
int size = (op >> 6) & 0x03;
int mode = (op >> 3) & 0x07;
int reg = op & 0x07;
int pc = info.PC + 2;
switch (size)
{
case 0: // Byte
info.Mnemonic = "neg.b";
info.Args = DisassembleValue(mode, reg, 1, ref pc);
break;
case 1: // Word
info.Mnemonic = "neg.w";
info.Args = DisassembleValue(mode, reg, 2, ref pc);
break;
case 2: // Long
info.Mnemonic = "neg.l";
info.Args = DisassembleValue(mode, reg, 4, ref pc);
break;
}
info.Length = pc - info.PC;
}
void CMP()
{
int dReg = (op >> 9) & 7;

1
BizHawk.Emulation/CPUs/68000/OpcodeTable.cs
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@ -35,6 +35,7 @@ namespace BizHawk.Emulation.CPUs.M68000
Assign("or", OR0, "1000", "Xn", "0", "Size2_1", "AmXn");
Assign("or", OR1, "1000", "Xn", "1", "Size2_1", "AmXn");
Assign("not", NOT, "01000110", "Size2_1", "AmXn");
Assign("neg", NEG, "01000100", "Size2_1", "AmXn");
Assign("jmp", JMP, "0100111011", "AmXn");
Assign("jsr", JSR, "0100111010", "AmXn");