private static Word PopValue(CpuRegister sp, Memory memory)
{
Word value = memory.Read(sp.Value);
sp.Increment();
return(value);
}
/// <summary>
/// 命令を実行します。
/// </summary>
/// <param name="rR1Field">命令語の中の r/r1 フィールドの値です。</param>
/// <param name="xR2Field">命令語の中の x/r2 フィールドの値です。</param>
/// <param name="registerSet">COMET II の一そろいのレジスタです。</param>
/// <param name="memory">COMET II の主記憶です。</param>
internal void Execute(UInt16 rR1Field, UInt16 xR2Field, CpuRegisterSet registerSet, Memory memory)
{
CpuRegister r = m_registerHandler.GetRegister(rR1Field, registerSet);
Word operand = m_operandHandler.GetOperand(xR2Field, registerSet, memory);
m_operator.Operate(r, operand, registerSet, memory);
}
private static void DoJump(Boolean condition, Word operand, CpuRegister pr)
{
if (condition)
{
pr.Value = operand;
}
}
private static void UnconditionalJumpAction(
CpuRegister r, Word operand, CpuRegisterSet registerSet, Memory memory)
{
const Boolean Condition = true;
DoJump(Condition, operand, registerSet.PR);
}
private static void JumpOnOverflowAction(
CpuRegister r, Word operand, CpuRegisterSet registerSet, Memory memory)
{
Boolean condition = registerSet.FR.OF;
DoJump(condition, operand, registerSet.PR);
}
private static void JumpOnNonZeroAction(
CpuRegister r, Word operand, CpuRegisterSet registerSet, Memory memory)
{
Boolean condition = !registerSet.FR.ZF;
DoJump(condition, operand, registerSet.PR);
}
internal void OnReturingFromSubroutine(Object sender, ReturningFromSubroutineEventArgs e)
{
// RET 命令で SP が初期値ならば、実行を終了する。
CpuRegister sp = e.SP;
e.Cancel = (sp.Value == InitialSp);
}
/// <summary>
/// PR レジスタが指すアドレスの内容を読み出しその値を返します。
/// PR レジスタの内容に 1 を加えます。
/// </summary>
/// <param name="pr">Program Register (PR) です。</param>
/// <param name="memory">COMET II の主記憶です。</param>
/// <returns>PR レジスタが指すアドレスの内容を返します。</returns>
internal static Word Fetch(CpuRegister pr, Memory memory)
{
Word word = memory.Read(pr.Value);
pr.Increment();
return(word);
}
/// <summary>
/// それぞれのフラグの値を設定します。オーバーフローフラグは指定の値を、
/// サインフラグとゼロフラグは指定のレジスタの値から設定します。
/// </summary>
/// <param name="r">サインフラグとゼロフラグの値の設定に使用するレジスタです。</param>
/// <param name="overflowFlag">オーバーフローフラグに設定する値です。</param>
internal void SetFlags(CpuRegister r, Boolean overflowFlag)
{
Boolean signFlag = r.Value.IsMinus();
Boolean zeroFlag = r.Value.IsZero();
SetFlags(overflowFlag, signFlag, zeroFlag);
}
private static void LoadWithFrAction(
CpuRegister r, Word operand, CpuRegisterSet registerSet, Memory memory)
{
r.Value = operand;
const Boolean OverflowFlag = false;
registerSet.FR.SetFlags(r, OverflowFlag);
}
private static void JumpOnPlusAction(
CpuRegister r, Word operand, CpuRegisterSet registerSet, Memory memory)
{
FlagRegister fr = registerSet.FR;
Boolean condition = (!fr.SF && !fr.ZF);
DoJump(condition, operand, registerSet.PR);
}
private static void CallSubroutineAction(
CpuRegister r, Word operand, CpuRegisterSet registerSet, Memory memory)
{
CpuRegister pr = registerSet.PR;
PushValue(registerSet.SP, memory, pr.Value);
pr.Value = operand;
}
private static Word DoGetRegister(UInt16 xR2Field, CpuRegisterSet registerSet)
{
ArgChecker.CheckRange(xR2Field, 0, RegisterDef.GrCount - 1, "x/r2");
CpuRegister x = registerSet.GR[xR2Field];
return(x.Value);
}
private static void DoOperation(
Alu.OperationMethod operationMethod, CpuRegister r, Word operand, FlagRegister fr, Memory memory)
{
Boolean overflowFlag;
r.Value = operationMethod(r.Value, operand, out overflowFlag);
fr.SetFlags(r, overflowFlag);
}
/// <summary>
/// <see cref="CpuRegisterSet"/> のインスタンスを初期化します。
/// </summary>
internal CpuRegisterSet()
{
m_generalRegisters = new GeneralRegisters();
m_stackPointer = new CpuRegister(RegisterDef.SP);
m_programRegister = new CpuRegister(RegisterDef.PR);
m_flagRegister = new FlagRegister();
Reset();
}
private static void DoShift(
Alu.ShiftMethod shiftMethod, CpuRegister r, Word operand, FlagRegister fr)
{
UInt16 lastShiftedOutBit;
r.Value = shiftMethod(r.Value, operand, out lastShiftedOutBit);
Boolean overflowFlag = (lastShiftedOutBit != 0);
fr.SetFlags(r, overflowFlag);
}
private static void DoCompare(
Alu.CompareMethod compareMethod, CpuRegister r, Word operand, FlagRegister fr)
{
Boolean signFlag;
Boolean zeroFlag;
compareMethod(r.Value, operand, out signFlag, out zeroFlag);
const Boolean OverflowFlag = false;
fr.SetFlags(OverflowFlag, signFlag, zeroFlag);
}
private static void ReturnFromSubroutineAction(
CpuRegister r, Word operand, CpuRegisterSet registerSet, Memory memory)
{
Boolean cancel = OnReturningFromSubroutine(registerSet.SP);
if (!cancel)
{
CpuRegister pr = registerSet.PR;
pr.Value = PopValue(registerSet.SP, memory);
}
}
private static void DoLogic(
Alu.OperationMethod operationMethod, CpuRegister r, Word operand, FlagRegister fr, Memory memory)
{
Boolean notUsed;
r.Value = operationMethod(r.Value, operand, out notUsed);
const Boolean OverflowFlag = false;
fr.SetFlags(r, OverflowFlag);
}
private static Boolean OnReturningFromSubroutine(CpuRegister sp)
{
Boolean cancel = false;
if (ReturningFromSubroutine != null)
{
ReturningFromSubroutineEventArgs e = new ReturningFromSubroutineEventArgs(sp);
ReturningFromSubroutine(null, e);
cancel = e.Cancel;
}
return(cancel);
}
private static void AddLogicalAction(
CpuRegister r, Word operand, CpuRegisterSet registerSet, Memory memory)
{
DoOperation(Alu.AddLogical, r, operand, registerSet.FR, memory);
}
private static void SubtractArithmeticAction(
CpuRegister r, Word operand, CpuRegisterSet registerSet, Memory memory)
{
DoOperation(Alu.SubtractArithmetic, r, operand, registerSet.FR, memory);
}
private static void LoadWithoutFrAction(
CpuRegister r, Word operand, CpuRegisterSet registerSet, Memory memory)
{
r.Value = operand;
}
/// <summary>
/// 演算を実行します。
/// </summary>
/// <param name="r">演算に使用するレジスタです。</param>
/// <param name="operand">演算対象の値を保持する語です。</param>
/// <param name="registerSet">COMET II の一そろいのレジスタです。</param>
/// <param name="memory">COMET II の主記憶です。</param>
internal void Operate(CpuRegister r, Word operand, CpuRegisterSet registerSet, Memory memory)
{
m_operateAction(r, operand, registerSet, memory);
}
private static void PopAction(
CpuRegister r, Word operand, CpuRegisterSet registerSet, Memory memory)
{
r.Value = PopValue(registerSet.SP, memory);
}
private static void NoOperationAction(
CpuRegister r, Word operand, CpuRegisterSet registerSet, Memory memory)
{
//
}
private static void SuperVisorCallAction(
CpuRegister r, Word operand, CpuRegisterSet registerSet, Memory memory)
{
OnCallingSuperVisor(operand);
}
private static void PushAction(
CpuRegister r, Word operand, CpuRegisterSet registerSet, Memory memory)
{
PushValue(registerSet.SP, memory, operand);
}
private static void StoreAction(
CpuRegister r, Word operand, CpuRegisterSet registerSet, Memory memory)
{
memory.Write(operand, r.Value);
}
private static void PushValue(CpuRegister sp, Memory memory, Word value)
{
sp.Decrement();
memory.Write(sp.Value, value);
}
