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6502bench/SourceGen/SystemDefaults.cs

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/*
* Copyright 2019 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.Collections.Generic;
using System.Diagnostics;
using Asm65;
using TextScanMode = SourceGen.ProjectProperties.AnalysisParameters.TextScanMode;
namespace SourceGen {
/// <summary>
/// Helper functions for extracting values from a SystemDef instance.
/// </summary>
public static class SystemDefaults {
private const string LOAD_ADDRESS = "load-address";
private const string ENTRY_FLAGS = "entry-flags";
private const string UNDOCUMENTED_OPCODES = "undocumented-opcodes";
private const string TWO_BYTE_BRK = "two-byte-brk";
private const string FIRST_WORD_IS_LOAD_ADDR = "first-word-is-load-addr";
private const string DEFAULT_TEXT_ENCODING = "default-text-encoding";
private const string ENTRY_FLAG_EMULATION = "emulation";
private const string ENTRY_FLAG_NATIVE_LONG = "native-long";
private const string ENTRY_FLAG_NATIVE_SHORT = "native-short";
private const string TEXT_ENCODING_C64_PETSCII = "c64-petscii";
/// <summary>
/// Gets the default load address.
/// </summary>
/// <param name="sysDef">SystemDef instance.</param>
/// <returns>Specified load address, or 0x1000 if nothing defined.</returns>
public static int GetLoadAddress(SystemDef sysDef) {
Dictionary<string, string> parms = sysDef.Parameters;
int retVal = 0x1000;
if (parms.TryGetValue(LOAD_ADDRESS, out string valueStr)) {
valueStr = valueStr.Trim();
if (Number.TryParseInt(valueStr, out int parseVal, out int unused)) {
retVal = parseVal;
} else {
Debug.WriteLine("WARNING: bad value for " + LOAD_ADDRESS + ": " + valueStr);
}
}
return retVal;
}
/// <summary>
/// Gets the default entry processor status flags.
/// </summary>
/// <param name="sysDef">SystemDef instance.</param>
/// <returns>Status flags.</returns>
public static StatusFlags GetEntryFlags(SystemDef sysDef) {
Dictionary<string, string> parms = sysDef.Parameters;
StatusFlags retFlags = StatusFlags.AllIndeterminate;
// On 65802/65816, this selects emulation mode. On 8-bit CPUs, these have
// no effect, but this reflects how the CPU behaves (short regs, emu mode).
retFlags.E = retFlags.M = retFlags.X = 1;
// Decimal mode is rarely used, and interrupts are generally enabled. Projects
// that need to assume otherwise can alter the entry flags. I want to start
// with decimal mode clear because it affects the cycle timing display on a
// number of 65C02 instructions.
retFlags.D = retFlags.I = 0;
if (parms.TryGetValue(ENTRY_FLAGS, out string valueStr)) {
switch (valueStr) {
case ENTRY_FLAG_EMULATION:
break;
case ENTRY_FLAG_NATIVE_LONG:
retFlags.E = retFlags.M = retFlags.X = 0;
break;
case ENTRY_FLAG_NATIVE_SHORT:
retFlags.E = 0;
break;
default:
Debug.WriteLine("WARNING: bad value for " + ENTRY_FLAGS +
": " + valueStr);
break;
}
}
return retFlags;
}
/// <summary>
/// Gets the default setting for undocumented opcode support.
/// </summary>
/// <param name="sysDef">SystemDef instance.</param>
/// <returns>Enable/disable value.</returns>
public static bool GetUndocumentedOpcodes(SystemDef sysDef) {
return GetBoolParam(sysDef, UNDOCUMENTED_OPCODES, false);
}
/// <summary>
/// Gets the default setting for two-byte BRKs.
/// </summary>
/// <param name="sysDef">SystemDef instance.</param>
/// <returns>Enable/disable value.</returns>
public static bool GetTwoByteBrk(SystemDef sysDef) {
return GetBoolParam(sysDef, TWO_BYTE_BRK, false);
}
/// <summary>
/// Gets the default setting for using the first two bytes of the file as the
/// load address.
///
/// This is primarily for C64 PRG files. Apple II DOS 3.3 binary files also put the
/// load address first, followed by the length, but that's typically stripped out when
/// the file is extracted.
/// </summary>
/// <param name="sysDef">SystemDef instance.</param>
/// <returns>True if the first word holds the load address.</returns>
public static bool GetFirstWordIsLoadAddr(SystemDef sysDef) {
return GetBoolParam(sysDef, FIRST_WORD_IS_LOAD_ADDR, false);
}
/// <summary>
/// Gets the default setting for the text scan encoding mode.
/// </summary>
/// <param name="sysDef">SystemDef instance.</param>
/// <returns>Preferred text scan mode.</returns>
public static TextScanMode GetTextScanMode(SystemDef sysDef) {
Dictionary<string, string> parms = sysDef.Parameters;
TextScanMode mode = TextScanMode.LowHighAscii;
if (parms.TryGetValue(DEFAULT_TEXT_ENCODING, out string valueStr)) {
if (valueStr == TEXT_ENCODING_C64_PETSCII) {
mode = TextScanMode.C64Petscii;
}
}
return mode;
}
/// <summary>
/// Looks for a parameter with a matching name and a boolean value.
/// </summary>
/// <param name="sysDef">SystemDef reference.</param>
/// <param name="paramName">Name of parameter to look for.</param>
/// <param name="defVal">Default value.</param>
/// <returns>Parsed value, or defVal if the parameter doesn't exist or the value is not
/// a boolean string.</returns>
private static bool GetBoolParam(SystemDef sysDef, string paramName, bool defVal) {
Dictionary<string, string> parms = sysDef.Parameters;
bool retVal = defVal;
if (parms.TryGetValue(paramName, out string valueStr)) {
if (bool.TryParse(valueStr, out bool parseVal)) {
retVal = parseVal;
} else {
Debug.WriteLine("WARNING: bad value for " + paramName + ": " + valueStr);
}
}
return retVal;
}
}
}