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6502bench/PluginCommon/Util.cs
Andy McFadden dfd5bcab1b Optionally treat BRKs as two-byte instructions
Early data sheets listed BRK as one byte, but RTI after a BRK skips
the following byte, effectively making BRK a 2-byte instruction.
Sometimes, such as when diassembling Apple /// SOS code, it's handy
to treat it that way explicitly.

This change makes two-byte BRKs optional, controlled by a checkbox
in the project settings.  In the system definitions it defaults to
true for Apple ///, false for all others.

ACME doesn't allow BRK to have an arg, and cc65 only allows it for
65816 code (?), so it's emitted as a hex blob for those assemblers.
Anyone wishing to target those assemblers should stick to 1-byte mode.

Extension scripts have to switch between formatting one byte of
inline data and formatting an instruction with a one-byte operand.
A helper function has been added to the plugin Util class.

To get some regression test coverage, 2022-extension-scripts has
been configured to use two-byte BRK.

Also, added/corrected some SOS constants.

See also issue #44.
2019-10-09 14:55:56 -07:00

89 lines
4.0 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 CommonUtil;
namespace PluginCommon {
/// <summary>
/// Utility functions available for plugins to use.
///
/// The idea is to make CommonUtil functions available to plugins while isolating
/// them from changes to the library. Anything here is guaranteed to keep working,
/// while other classes and functions in CommonUtil may change between releases.
/// </summary>
public static class Util {
/// <summary>
/// Extracts an integer from the data stream.
/// </summary>
/// <param name="data">Raw data stream.</param>
/// <param name="offset">Start offset.</param>
/// <param name="width">Word width, which may be 1-4 bytes.</param>
/// <param name="isBigEndian">True if word is in big-endian order.</param>
/// <returns>Value found.</returns>
public static int GetWord(byte[] data, int offset, int width, bool isBigEndian) {
return RawData.GetWord(data, offset, width, isBigEndian);
}
/// <summary>
/// Determines whether the provided offset and length are valid for the array.
/// </summary>
/// <param name="data">Data array that to check against.</param>
/// <param name="startOff">Start offset.</param>
/// <param name="len">Number of bytes.</param>
/// <returns>True if the specified range falls within the array bounds.</returns>
public static bool IsInBounds(byte[] data, int startOff, int len) {
return !(startOff < 0 || len < 0 || startOff >= data.Length || len > data.Length ||
startOff + len > data.Length);
}
/// <summary>
/// Computes a standard CRC-32 (polynomial 0xedb88320) on a buffer of data.
/// </summary>
/// <param name="data">Buffer to process.</param>
/// <returns>CRC value.</returns>
public static uint ComputeBufferCRC(byte[] data) {
return CRC32.OnBuffer(0, data, 0, data.Length);
}
/// <summary>
/// Formats the byte that follows a BRK instruction. How we do this depends on
/// whether the system is configured for two-byte BRKs.
/// </summary>
/// <remarks>
/// We can actually apply the format both ways and let the app ignore the one it
/// doesn't like, but this is cleaner.
/// </remarks>
/// <param name="appRef">Reference to application object.</param>
/// <param name="twoByteBrk">True if BRKs are handled as two-byte instructions.</param>
/// <param name="brkOffset">Offset of BRK instruction.</param>
/// <param name="type">Data type to apply.</param>
/// <param name="subType">Data sub-type to apply.</param>
/// <param name="label">Label, for subType=Symbol.</param>
public static void FormatBrkByte(IApplication appRef, bool twoByteBrk, int brkOffset,
DataSubType subType, string label) {
if (twoByteBrk) {
// Two-byte BRK, so we want to apply the format to the instruction itself.
appRef.SetOperandFormat(brkOffset, subType, label);
} else {
// Single-byte BRK, so we want to format the byte that follows the
// instruction as inline data.
appRef.SetInlineDataFormat(brkOffset + 1, 1, DataType.NumericLE, subType, label);
}
}
}
}