/// <summary>
/// Obtains the <see cref="Opcode"/> instance for the given value.
/// </summary>
/// <param name="value">The value of the opcode.</param>
/// <returns>The corresponding <see cref="Opcode"/> instance, or <c>null</c> if there is none.</returns>
public static Opcode FromValue(OpcodeValue value)
{
if (value.GetByteCount() == 1)
{
return(Lookup.oneByte[(int)value]);
}
else
{
Opcode opcode;
Lookup.twoByte.TryGetValue((ushort)value, out opcode);
return(opcode);
}
}
public static int GetByteCount(this OpcodeValue value)
{
return(HasTwoBytes(value) ? 2 : 1);
}
public static bool HasTwoBytes(this OpcodeValue value)
{
return((int)value >= 0x100);
}
public static byte GetSecondByte(this OpcodeValue value)
{
Contract.Requires(HasTwoBytes(value));
return(unchecked ((byte)value));
}
public static byte GetFirstByte(this OpcodeValue value)
{
return(unchecked (HasTwoBytes(value) ? (byte)((ushort)value >> 8) : (byte)value));
}
internal Opcode(OpcodeValue code, params IByteCode[] parameters) : base((byte)code, parameters)
{
this.code = code;
}
private OpcodeInfo(OpcodeValue code, string comment, string arguments,
Action <OpcodeInfo, VirtualMachine.SegmentInfo, ushort, IndentedTextWriter>?writer = null,
string?stackBefore = null, string?stackAfter = null)
{
this.Code = code;
this.Comment = comment;
this.arguments = arguments;
this.stackBefore = stackBefore;
this.stackAfter = stackAfter;
if (writer != null)
{
this.Write = writer;
return;
}
this.Write = (o, si, j, w) =>
{
var lastArg = 0;
var times = 1;
foreach (var argument in o.arguments)
{
switch (argument)
{
case 'B':
while (--times >= 0)
{
w.Write(" 0x{0:X2}", lastArg = VM.FetchByte());
}
break;
case 'N':
case 'S':
while (--times >= 0)
{
w.Write(" " + (lastArg = VM.FetchSignedByte()));
}
break;
case 'W':
while (--times >= 0)
{
w.Write(" 0x{0:X4}", lastArg = VM.FetchWord());
}
break;
case 'C':
while (--times >= 0)
{
w.Write(" 0x{0:X4}", lastArg = VM.FetchBig());
}
break;
case 'A':
var bytes = new byte[times];
for (var i = 0; i < times; i++)
{
lastArg = bytes[i] = VM.FetchByte();
}
w.Write(" \"{0}\"", VM.Escape(Encoding.ASCII.GetString(bytes)));
break;
case '*':
times = lastArg - 2;
break;
}
times += 2;
}
};
}
public OpcodeInfo(OpcodeValue code, string comment, string arguments, string stackBefore,
string?stackAfter = null)
: this(code, comment, arguments, null, stackBefore, stackAfter)
{
}
