public override void FormatInstruction(TextWriter writer, Context ctx, Instruction inst)
{
// label or indent
if (inst.Parent == null)
{
writer.Write(INDENT);
}
else
{
writer.Write(INST_LABEL, inst.PC);
}
ZOpAttribute attr = ctx.GetOpcodeInfo(inst.Op);
// instruction name
writer.Write('@');
writer.Write(attr.InformName);
// regular operands
ushort[] operands = inst.Operands;
OperandType[] otypes = inst.OperandTypes;
for (int i = 0; i < otypes.Length; i++)
{
switch (otypes[i])
{
case OperandType.Word:
case OperandType.Byte:
writer.Write(' ');
writer.Write((short)operands[i]);
break;
case OperandType.Variable:
writer.Write(' ');
writer.Write(FormatVariable(operands[i]));
break;
}
}
// text
ushort[] text = inst.EncodedText;
if (text != null)
{
writer.Write(" \"");
foreach (char c in ctx.DecodeText(text))
{
switch (c)
{
case '\n':
writer.Write('^');
break;
case '"':
writer.Write('\"');
break;
default:
//XXX handle @ and other characters that need escaping
writer.Write(c);
break;
}
}
writer.Write('"');
}
// store target
if (inst.StoreTarget != null)
{
writer.Write(" -> ");
writer.Write(FormatVariable(inst.StoreTarget.Value));
}
// branch target
if (inst.BranchType != BranchType.None)
{
writer.Write(" ?");
switch (inst.BranchType)
{
case BranchType.LongNegative:
case BranchType.ShortNegative:
writer.Write('~');
break;
}
switch (inst.BranchOffset)
{
case 0:
writer.Write("rfalse");
break;
case 1:
writer.Write("rtrue");
break;
default:
writer.Write("zc_{0:x5}", inst.PC + inst.Length + inst.BranchOffset - 2);
break;
}
}
// done
writer.WriteLine(';');
}
public static Instruction Decode(Context ctx, BinaryReader rdr, int pc)
{
int length = 1;
// read opcode number and look up opcode info
ushort op = rdr.ReadByte();
if (op == 190 && ctx.ZVersion >= 5)
{
op = (ushort)(256 + rdr.ReadByte());
length++;
}
// canonicalize opcode number and decode operand types
OperandType[] otypes;
if (op < 128)
{
// long, 2OP
otypes = new OperandType[2];
if ((op & 0x40) == 0)
{
otypes[0] = OperandType.Byte;
}
else
{
otypes[0] = OperandType.Variable;
}
if ((op & 0x20) == 0)
{
otypes[1] = OperandType.Byte;
}
else
{
otypes[1] = OperandType.Variable;
}
op &= 0x1f; // clear operand type bits
}
else if (op < 192)
{
// short
if (op < 176)
{
// 1OP
otypes = new[] { (OperandType)((op >> 4) & 3) };
op &= 0xcf; // clear operand type bits
}
else
{
// 0OP
otypes = new OperandType[] { };
}
}
else
{
// variable
if (op == 236 || op == 250)
{
otypes = new OperandType[8];
}
else
{
otypes = new OperandType[4];
}
if (op < 224)
{
// 2OP
op &= 0x1f; // translate to 2OP opcode number
}
// otherwise VAR (op < 256) or EXT
for (int i = 0; 4 * i < otypes.Length; i++)
{
byte b = rdr.ReadByte();
length++;
otypes[4 * i] = (OperandType)((b >> 6) & 3);
otypes[4 * i + 1] = (OperandType)((b >> 4) & 3);
otypes[4 * i + 2] = (OperandType)((b >> 2) & 3);
otypes[4 * i + 3] = (OperandType)(b & 3);
}
}
// look up opcode info
ZOpAttribute attr = ctx.GetOpcodeInfo(op);
if (attr == null)
{
return(null);
}
// read operand values
ushort[] operands = new ushort[otypes.Length];
for (int i = 0; i < otypes.Length; i++)
{
switch (otypes[i])
{
case OperandType.Word:
operands[i] = rdr.ReadZWord();
length += 2;
break;
case OperandType.Byte:
case OperandType.Variable:
operands[i] = rdr.ReadByte();
length++;
break;
}
}
// read store/branch targets
byte?storeTarget = null;
if ((attr.Flags & ZOpFlags.Store) != 0)
{
storeTarget = rdr.ReadByte();
length++;
}
BranchType branchType;
short branchOffset = 0;
if ((attr.Flags & ZOpFlags.Branch) != 0)
{
byte b = rdr.ReadByte();
length++;
branchType = (BranchType)(b & 0xc0);
switch (branchType)
{
case BranchType.LongNegative:
case BranchType.LongPositive:
// signed 14-bit offset: last 6 bits of b followed by all 8 of the next byte
// we shift right by 2 to extend the sign from 14 to 16 bits
short s = (short)(((b & 0x3f) << 10) | (rdr.ReadByte() << 2));
length++;
branchOffset = (short)(s >> 2);
break;
case BranchType.ShortNegative:
case BranchType.ShortPositive:
// unsigned 6-bit offset: last 6 bits of b
branchOffset = (short)(b & 0x3f);
break;
}
}
else
{
branchType = BranchType.None;
}
// read text
ushort[] encodedText = null;
if ((attr.Flags & ZOpFlags.String) != 0)
{
List <ushort> list = new List <ushort>();
ushort w;
do
{
w = rdr.ReadZWord();
length += 2;
list.Add(w);
} while ((w & 0x8000) == 0);
encodedText = list.ToArray();
}
// done
var result = new Instruction(pc, length)
{
branchOffset = branchOffset,
branchType = branchType,
encodedText = encodedText,
op = op,
operandTypes = otypes,
operands = operands,
storeTarget = storeTarget
};
return(result);
}
public override void FormatInstruction(TextWriter writer, Context ctx, Instruction inst)
{
// label or indent
if (inst.Parent == null)
{
writer.Write(INDENT);
}
else
{
writer.Write(INST_LABEL, inst.PC);
}
ZOpAttribute attr = ctx.GetOpcodeInfo(inst.Op);
// instruction name
writer.Write(attr.ClassicName);
// regular operands
ushort[] operands = inst.Operands;
OperandType[] otypes = inst.OperandTypes;
bool any = false;
for (int i = 0; i < otypes.Length; i++)
{
switch (otypes[i])
{
case OperandType.Word:
case OperandType.Byte:
if (!any)
{
writer.Write(' ');
any = true;
}
else
{
writer.Write(',');
}
if (i == 0)
{
if ((attr.Flags & ZOpFlags.Call) != 0)
{
writer.Write("ZR${0:X4}", operands[i]);
continue;
}
if ((attr.Flags & ZOpFlags.Label) != 0)
{
writer.Write("ZC${0:X5}", inst.PC + inst.Length + (short)operands[i] - 2);
continue;
}
if ((attr.Flags & ZOpFlags.IndirectVar) != 0)
{
writer.Write('\'');
writer.Write(FormatVariable(operands[i]));
continue;
}
}
writer.Write((short)operands[i]);
break;
case OperandType.Variable:
if (!any)
{
writer.Write(' ');
any = true;
}
else
{
writer.Write(',');
}
writer.Write(FormatVariable(operands[i]));
break;
}
}
// text
ushort[] text = inst.EncodedText;
if (text != null)
{
writer.Write(" \"");
foreach (char c in ctx.DecodeText(text))
{
switch (c)
{
case '"':
writer.Write("\"\"");
break;
default:
writer.Write(c);
break;
}
}
writer.Write('"');
}
// store target
if (inst.StoreTarget != null)
{
writer.Write(" >");
writer.Write(FormatVariable(inst.StoreTarget.Value));
}
// branch target
if (inst.BranchType != BranchType.None)
{
switch (inst.BranchType)
{
case BranchType.LongNegative:
case BranchType.ShortNegative:
writer.Write(" \\");
break;
case BranchType.LongPositive:
case BranchType.ShortPositive:
writer.Write(" /");
break;
}
switch (inst.BranchOffset)
{
case 0:
writer.Write("FALSE");
break;
case 1:
writer.Write("TRUE");
break;
default:
writer.Write("ZC${0:X5}", inst.PC + inst.Length + inst.BranchOffset - 2);
break;
}
}
writer.WriteLine();
}
