/*
* 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.Collections.Generic;
using System.Diagnostics;
using Asm65;
namespace SourceGen.Setup {
public 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 ENTRY_FLAG_EMULATION = "emulation";
private const string ENTRY_FLAG_NATIVE_LONG = "native-long";
private const string ENTRY_FLAG_NATIVE_SHORT = "native-short";
///
/// Gets the default load address.
///
/// SystemDef instance.
/// Load address.
public static int GetLoadAddress(SystemDef sysDef) {
Dictionary 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;
}
///
/// Gets the default entry processor status flags.
///
/// SystemDef instance.
/// Status flags.
public static StatusFlags GetEntryFlags(SystemDef sysDef) {
Dictionary 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;
}
///
/// Gets the default setting for undocumented opcode support.
///
/// SystemDef instance.
/// Enable/disable value.
public static bool GetUndocumentedOpcodes(SystemDef sysDef) {
Dictionary parms = sysDef.Parameters;
bool retVal = false;
if (parms.TryGetValue(UNDOCUMENTED_OPCODES, out string valueStr)) {
if (bool.TryParse(valueStr, out bool parseVal)) {
retVal = parseVal;
} else {
Debug.WriteLine("WARNING: bad value for " + UNDOCUMENTED_OPCODES +
": " + valueStr);
}
}
return retVal;
}
}
}