private static void STA(CPU cpu) //Store Address
{
//Result stores orignal core storage word with bits 21-35 replaced by the
//accumulator 21-35 bits
string fromCore = cpu.GetCoreStorageWord(cpu.IndexedAddress).Substring(0, 21);
string fromAccum = cpu.AccumulatorReg.Bits_SignTo35.Substring(21, 15);
string result = fromCore + fromAccum;
cpu.SetCoreStorageWord(result, cpu.IndexedAddress);
//Increment IRC
cpu.InstructionCounter.Increment(1);
}
/// <summary>
/// Floating Subtract 7-11 FSB Y +0302
/// </summary>
/// <param name="cpu"></param>
private static void FSB(CPU cpu)
{
FloatingPointNumber fromCore = new FloatingPointNumber(cpu.GetCoreStorageWord(cpu.IndexedAddress));
FloatingPointNumber fromAccum = new FloatingPointNumber(cpu.AccumulatorReg.Bits_SignTo35);
fromAccum.DecimalValue = fromAccum.DecimalValue - fromCore.DecimalValue;
cpu.AccumulatorReg.Bits_SignTo35 = fromAccum.Value;
cpu.AccumulatorReg.PBit = "0";
cpu.AccumulatorReg.QBit = "0";
cpu.MQReg.Value = fromAccum.Value;
cpu.InstructionCounter.Increment(1);
}
/// <summary>
/// This instruction algebraically subtracts the C(Y) from the C(AC) and replaces the C(AC) with
/// this difference. The C(Y) are unchanged. Ac overflow is possible
/// </summary>
/// <param name="cpu"></param>
private static void SUB(CPU cpu)
{
long fromCore = Converter.ConvertToInt(cpu.GetCoreStorageWord(cpu.IndexedAddress));
long fromAccum = Converter.ConvertToInt(cpu.AccumulatorReg.Bits_SignTo35);
long result = fromAccum - fromCore;
string newWord = Converter.ConvertToBinary(result, 36);
if (newWord.Length > 36)
{
cpu.AccumOverflowIndicator = true;
cpu.AccumulatorReg.Bits_SignTo35 = newWord.Substring(0, 36);
}
else
{
cpu.AccumulatorReg.Bits_SignTo35 = newWord;
}
cpu.InstructionCounter.Increment(1);
}
/// <summary>
/// Multiply
///20 MPY Y +0200
///This instruction multiplies the c (Y) by the c(MQ) . The 3 5 most significant bits of the 70-bit product
/// replace the C(AC)1.35 and the 3 5 least significant bits replace the c (MQ) !_35. The Q and P bits are
/// cleared. The sign of the AC is the algebraic sign of the product. The sign of the MQ agrees with the sign
/// of the AC.
/// Placing of the binary point in the factors is com¬pletely arbitrary. A simple familiar rule to remember
/// with regard to placing the binary point in the result¬ing product follows.
/// RULE: Add the number of binary bits to the right of the binary point in the first factor to the number
/// of binary bits to the right of the binary point in the second factor. This sum is the number of bits
/// appear¬ing to the right of the binary point in the product.
/// </summary>
/// <param name="cpu"></param>
private static void MPY(CPU cpu)
{
long fromCore = Converter.ConvertToInt(cpu.GetCoreStorageWord(cpu.IndexedAddress));
long fromAccum = Converter.ConvertToInt(cpu.AccumulatorReg.Bits_SignTo35);
long result = fromCore * fromAccum;
//Include one extra bit for the sign
string newWord = Converter.ConvertToBinary(result, 71);
cpu.AccumulatorReg.PBit = "0";
cpu.AccumulatorReg.QBit = "0";
if (newWord.Length > 71)
{
cpu.AccumOverflowIndicator = true;
}
cpu.AccumulatorReg.Bits_SignTo35 = newWord.Substring(0, 36);
cpu.MQReg.Value = "0" + newWord.Substring(36, 35);
cpu.InstructionCounter.Increment(1);
}
