mirror of
https://github.com/fadden/6502bench.git
synced 2024-11-26 06:49:19 +00:00
329 lines
11 KiB
C#
329 lines
11 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.Text;
|
|
|
|
namespace Asm65 {
|
|
/// <summary>
|
|
/// Status flag holder. Each flag may be known to be zero, known to be one, or
|
|
/// hold an indeterminate value (represented as a negative number).
|
|
///
|
|
/// For the 65802/65816, we also keep track of the E flag (emulation bit), even though
|
|
/// that's not actually held in the P register.
|
|
///
|
|
/// Note this is a value type, not a reference type.
|
|
///
|
|
/// The default value is UNSPECIFIED for all bits.
|
|
/// </summary>
|
|
public struct StatusFlags {
|
|
private TriState16 mState;
|
|
|
|
|
|
/// <summary>
|
|
/// Flag bits, from processor status register definition. The 'e' (emulation)
|
|
/// flag from the 65816 is tacked onto the end.
|
|
///
|
|
/// The enumerated value matches the bit number in the P register.
|
|
/// </summary>
|
|
public enum FlagBits {
|
|
C = 0,
|
|
Z = 1,
|
|
I = 2,
|
|
D = 3,
|
|
B = 4, // all CPUs except 65802/65816 in native mode
|
|
X = 4, // 65802/65816 in native mode
|
|
M = 5, // 65802/65816 in native mode (always 1 on other CPUs)
|
|
V = 6,
|
|
N = 7,
|
|
E = 8 // not actually part of P-reg; accessible only through XCE
|
|
}
|
|
|
|
/// <summary>
|
|
/// Default value (all flags UNSPECIFIED). A newly-created array of StatusFlags will
|
|
/// all have this value.
|
|
/// </summary>
|
|
public static readonly StatusFlags DefaultValue =
|
|
new StatusFlags { mState = new TriState16(0, 0) };
|
|
|
|
/// <summary>
|
|
/// All flags are INDETERMINATE.
|
|
/// </summary>
|
|
public static readonly StatusFlags AllIndeterminate =
|
|
new StatusFlags() { mState = new TriState16(0x01ff, 0x01ff) };
|
|
|
|
public int C {
|
|
get {
|
|
return mState.GetBit((int)FlagBits.C);
|
|
}
|
|
set {
|
|
if (value == 0) {
|
|
mState.SetZero((int)FlagBits.C);
|
|
} else if (value == 1) {
|
|
mState.SetOne((int)FlagBits.C);
|
|
} else if (value == TriState16.UNSPECIFIED) {
|
|
mState.SetUnspecified((int)FlagBits.C);
|
|
} else {
|
|
mState.SetIndeterminate((int)FlagBits.C);
|
|
}
|
|
}
|
|
}
|
|
|
|
public int Z {
|
|
get {
|
|
return mState.GetBit((int)FlagBits.Z);
|
|
}
|
|
set {
|
|
if (value == 0) {
|
|
mState.SetZero((int)FlagBits.Z);
|
|
} else if (value == 1) {
|
|
mState.SetOne((int)FlagBits.Z);
|
|
} else if (value == TriState16.UNSPECIFIED) {
|
|
mState.SetUnspecified((int)FlagBits.Z);
|
|
} else {
|
|
mState.SetIndeterminate((int)FlagBits.Z);
|
|
}
|
|
}
|
|
}
|
|
|
|
public int I {
|
|
get {
|
|
return mState.GetBit((int)FlagBits.I);
|
|
}
|
|
set {
|
|
if (value == 0) {
|
|
mState.SetZero((int)FlagBits.I);
|
|
} else if (value == 1) {
|
|
mState.SetOne((int)FlagBits.I);
|
|
} else if (value == TriState16.UNSPECIFIED) {
|
|
mState.SetUnspecified((int)FlagBits.I);
|
|
} else {
|
|
mState.SetIndeterminate((int)FlagBits.I);
|
|
}
|
|
}
|
|
}
|
|
|
|
public int D {
|
|
get {
|
|
return mState.GetBit((int)FlagBits.D);
|
|
}
|
|
set {
|
|
if (value == 0) {
|
|
mState.SetZero((int)FlagBits.D);
|
|
} else if (value == 1) {
|
|
mState.SetOne((int)FlagBits.D);
|
|
} else if (value == TriState16.UNSPECIFIED) {
|
|
mState.SetUnspecified((int)FlagBits.D);
|
|
} else {
|
|
mState.SetIndeterminate((int)FlagBits.D);
|
|
}
|
|
}
|
|
}
|
|
|
|
public int X {
|
|
get {
|
|
return mState.GetBit((int)FlagBits.X);
|
|
}
|
|
set {
|
|
if (value == 0) {
|
|
mState.SetZero((int)FlagBits.X);
|
|
} else if (value == 1) {
|
|
mState.SetOne((int)FlagBits.X);
|
|
} else if (value == TriState16.UNSPECIFIED) {
|
|
mState.SetUnspecified((int)FlagBits.X);
|
|
} else {
|
|
mState.SetIndeterminate((int)FlagBits.X);
|
|
}
|
|
}
|
|
}
|
|
|
|
public int M {
|
|
get {
|
|
return mState.GetBit((int)FlagBits.M);
|
|
}
|
|
set {
|
|
if (value == 0) {
|
|
mState.SetZero((int)FlagBits.M);
|
|
} else if (value == 1) {
|
|
mState.SetOne((int)FlagBits.M);
|
|
} else if (value == TriState16.UNSPECIFIED) {
|
|
mState.SetUnspecified((int)FlagBits.M);
|
|
} else {
|
|
mState.SetIndeterminate((int)FlagBits.M);
|
|
}
|
|
}
|
|
}
|
|
|
|
public int V {
|
|
get {
|
|
return mState.GetBit((int)FlagBits.V);
|
|
}
|
|
set {
|
|
if (value == 0) {
|
|
mState.SetZero((int)FlagBits.V);
|
|
} else if (value == 1) {
|
|
mState.SetOne((int)FlagBits.V);
|
|
} else if (value == TriState16.UNSPECIFIED) {
|
|
mState.SetUnspecified((int)FlagBits.V);
|
|
} else {
|
|
mState.SetIndeterminate((int)FlagBits.V);
|
|
}
|
|
}
|
|
}
|
|
|
|
public int N {
|
|
get {
|
|
return mState.GetBit((int)FlagBits.N);
|
|
}
|
|
set {
|
|
if (value == 0) {
|
|
mState.SetZero((int)FlagBits.N);
|
|
} else if (value == 1) {
|
|
mState.SetOne((int)FlagBits.N);
|
|
} else if (value == TriState16.UNSPECIFIED) {
|
|
mState.SetUnspecified((int)FlagBits.N);
|
|
} else {
|
|
mState.SetIndeterminate((int)FlagBits.N);
|
|
}
|
|
}
|
|
}
|
|
|
|
public int E {
|
|
get {
|
|
return mState.GetBit((int)FlagBits.E);
|
|
}
|
|
set {
|
|
if (value == 0) {
|
|
mState.SetZero((int)FlagBits.E);
|
|
} else if (value == 1) {
|
|
mState.SetOne((int)FlagBits.E);
|
|
} else if (value == TriState16.UNSPECIFIED) {
|
|
mState.SetUnspecified((int)FlagBits.E);
|
|
} else {
|
|
mState.SetIndeterminate((int)FlagBits.E);
|
|
}
|
|
}
|
|
}
|
|
|
|
public int GetBit(FlagBits index) {
|
|
return mState.GetBit((int) index);
|
|
}
|
|
|
|
/// <summary>
|
|
/// Returns true if the current processor status flags are configured for a short
|
|
/// (8-bit) accumulator.
|
|
/// </summary>
|
|
public bool ShortM {
|
|
get {
|
|
// E==1 --> true (we're in emulation mode)
|
|
// E==0 || E==? : native / assumed native
|
|
// M==1 || M==? --> true (native mode, configured short or assumed short)
|
|
// M==0 --> false (native mode, configured long)
|
|
return (E == 1) || (M != 0);
|
|
}
|
|
}
|
|
|
|
/// <summary>
|
|
/// Returns true if the current processor status flags are configured for short
|
|
/// (8-bit) X/Y registers.
|
|
/// </summary>
|
|
public bool ShortX {
|
|
get {
|
|
// (same logic as ShortM)
|
|
return (E == 1) || (X != 0);
|
|
}
|
|
}
|
|
|
|
/// <summary>
|
|
/// Access the value as a single integer. Used for serialization.
|
|
/// </summary>
|
|
public int AsInt {
|
|
get {
|
|
return mState.AsInt;
|
|
}
|
|
}
|
|
|
|
/// <summary>
|
|
/// Set the value from an integer. Used for serialization.
|
|
/// </summary>
|
|
public static StatusFlags FromInt(int value) {
|
|
if ((value & ~0x01ff01ff) != 0) {
|
|
throw new InvalidOperationException("Bad StatusFlags value " +
|
|
value.ToString("x8"));
|
|
}
|
|
StatusFlags newFlags = new StatusFlags();
|
|
newFlags.mState.AsInt = value;
|
|
return newFlags;
|
|
}
|
|
|
|
/// <summary>
|
|
/// Merge a set of status flags into this one.
|
|
/// </summary>
|
|
public void Merge(StatusFlags other) {
|
|
mState.Merge(other.mState);
|
|
}
|
|
|
|
/// <summary>
|
|
/// Applies flags, overwriting existing values. This will set one or more flags
|
|
/// to 0, 1, or indeterminate. Unspecified (0/0) values have no effect.
|
|
///
|
|
/// This is useful when merging "overrides" in.
|
|
/// </summary>
|
|
public void Apply(StatusFlags overrides) {
|
|
mState.Apply(overrides.mState);
|
|
}
|
|
|
|
/// <summary>
|
|
/// Returns a string representation of the flags.
|
|
/// </summary>
|
|
/// <param name="showMXE">If set, include the 'E' flag, and show M/X.</param>
|
|
public string ToString(bool showMXE) {
|
|
StringBuilder sb = new StringBuilder(showMXE ? 10 : 8);
|
|
sb.Append("-?nN"[N + 2]);
|
|
sb.Append("-?vV"[V + 2]);
|
|
sb.Append(showMXE ? "-?mM"[M + 2] : '-');
|
|
sb.Append(showMXE ? "-?xX"[X + 2] : '-');
|
|
sb.Append("-?dD"[D + 2]);
|
|
sb.Append("-?iI"[I + 2]);
|
|
sb.Append("-?zZ"[Z + 2]);
|
|
sb.Append("-?cC"[C + 2]);
|
|
if (showMXE) {
|
|
sb.Append(' ');
|
|
sb.Append("-?eE"[E + 2]);
|
|
}
|
|
return sb.ToString();
|
|
}
|
|
|
|
|
|
public static bool operator ==(StatusFlags a, StatusFlags b) {
|
|
return a.mState == b.mState;
|
|
}
|
|
public static bool operator !=(StatusFlags a, StatusFlags b) {
|
|
return !(a == b);
|
|
}
|
|
public override bool Equals(object obj) {
|
|
return obj is StatusFlags && this == (StatusFlags)obj;
|
|
}
|
|
public override int GetHashCode() {
|
|
return mState.GetHashCode();
|
|
}
|
|
|
|
public override string ToString() {
|
|
return ToString(true);
|
|
// + " [" + mState.ToString() + "]"
|
|
}
|
|
}
|
|
}
|