mirror of
https://github.com/fadden/6502bench.git
synced 2024-11-26 06:49:19 +00:00
95 lines
3.6 KiB
C#
95 lines
3.6 KiB
C#
/*
|
|
* Copyright 2018 faddenSoft
|
|
*
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
|
* you may not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*/
|
|
using System;
|
|
using System.Diagnostics;
|
|
|
|
namespace SourceGen {
|
|
/// <summary>
|
|
/// Weak reference to a symbol for use in an operand or data statement. The reference
|
|
/// is by name; if the symbol disappears or changes value, the reference can be ignored.
|
|
/// This also specifies which part of the numeric value is of interest, so we can reference
|
|
/// the high or low byte of a 16-bit value in (say) LDA #imm.
|
|
///
|
|
/// Instances are immutable.
|
|
/// </summary>
|
|
public class WeakSymbolRef {
|
|
/// <summary>
|
|
/// This identifies the part of the value that we're interested in. All values are
|
|
/// signed 32-bit integers.
|
|
/// </summary>
|
|
public enum Part {
|
|
// This indicates which byte we start with, useful for immediate operands
|
|
// and things like PEA. By popular convention, these are referred to as
|
|
// low, high, and bank.
|
|
//
|
|
// With 16-bit registers, Merlin 32 grabs the high *word*, while cc65's assembler
|
|
// grabs the high *byte*. One is a shift, the other is a byte select. We use
|
|
// low/high/bank just to mean position here.
|
|
//
|
|
// (Could make this orthogonal with a pair of bit fields, one for position and
|
|
// one for width, but there's really only three widths of interest (1, 2, 3 bytes)
|
|
// and that's defined by context.)
|
|
Unknown = 0,
|
|
Low, // LDA #label, LDA #<label
|
|
High, // LDA #>label
|
|
Bank, // LDA #^label
|
|
}
|
|
|
|
/// <summary>
|
|
/// Label of symbol of interest.
|
|
/// </summary>
|
|
public string Label { get; private set; }
|
|
|
|
/// <summary>
|
|
/// Which part of the value we're referencing.
|
|
/// </summary>
|
|
public Part ValuePart { get; private set; }
|
|
|
|
/// <summary>
|
|
/// Full constructor.
|
|
/// </summary>
|
|
public WeakSymbolRef(string label, Part part) {
|
|
Debug.Assert(label != null);
|
|
Label = label;
|
|
ValuePart = part;
|
|
}
|
|
|
|
public static bool operator ==(WeakSymbolRef a, WeakSymbolRef b) {
|
|
if (ReferenceEquals(a, b)) {
|
|
return true; // same object, or both null
|
|
}
|
|
if (ReferenceEquals(a, null) || ReferenceEquals(b, null)) {
|
|
return false; // one is null
|
|
}
|
|
return Asm65.Label.LABEL_COMPARER.Equals(a.Label, b.Label) &&
|
|
a.ValuePart == b.ValuePart;
|
|
}
|
|
public static bool operator !=(WeakSymbolRef a, WeakSymbolRef b) {
|
|
return !(a == b);
|
|
}
|
|
public override bool Equals(object obj) {
|
|
return obj is WeakSymbolRef && this == (WeakSymbolRef)obj;
|
|
}
|
|
public override int GetHashCode() {
|
|
return Asm65.Label.ToNormal(Label).GetHashCode() ^ (int)ValuePart;
|
|
}
|
|
|
|
public override string ToString() {
|
|
return "WeakSym: " + Label + ":" + ValuePart;
|
|
}
|
|
}
|
|
}
|