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Rationalise use of "intermediate" Register16

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This commit is contained in:
Adrian Conlon
2024-06-29 13:38:55 +01:00
parent 7f0ca27412
commit 6e46c8e47f
5 changed files with 65 additions and 70 deletions
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Z80/Z80.cs
+27 -26
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@@ -21,8 +21,6 @@ namespace EightBit
},
};
private readonly Register16 intermediate = new();
private RefreshRegister refresh = new(0x7f);
private bool prefixCB = false;
@@ -539,7 +537,9 @@ namespace EightBit
break;
case 2:
this.Tick(7);
this.Call(this.MEMPTR.Word = new Register16(data, this.IV).Word);
this.MEMPTR.Low = data;
this.MEMPTR.High = this.IV;
this.Call(this.MEMPTR.Word);
break;
default:
throw new NotSupportedException("Invalid interrupt mode");
@@ -762,7 +762,7 @@ namespace EightBit
break;
case 1: // BIT y, r[z]
this.BIT(y, operand);
this.F = direct ? AdjustXY(this.F, operand) : AdjustXY(this.F, this.MEMPTR.High);
this.F = AdjustXY(this.F, direct ? operand : this.MEMPTR.High);
break;
case 2: // RES y, r[z]
operand = RES(y, operand);
@@ -1591,14 +1591,14 @@ namespace EightBit
private byte Subtract(byte operand, byte value, int carry = 0)
{
this.intermediate.Word = (ushort)(operand - value - carry);
var result = this.intermediate.Low;
this.Intermediate.Word = (ushort)(operand - value - carry);
var result = this.Intermediate.Low;
this.F = AdjustHalfCarrySub(this.F, operand, value, result);
this.F = AdjustOverflowSub(this.F, operand, value, result);
this.F = SetBit(this.F, StatusBits.NF);
this.F = SetBit(this.F, StatusBits.CF, this.intermediate.High & (byte)StatusBits.CF);
this.F = SetBit(this.F, StatusBits.CF, this.Intermediate.High & (byte)StatusBits.CF);
this.F = AdjustSZ(this.F, result);
return result;
@@ -1663,66 +1663,66 @@ namespace EightBit
private ushort SBC(Register16 operand, Register16 value)
{
var subtraction = operand.Word - value.Word - (this.F & (byte)StatusBits.CF);
this.intermediate.Word = (ushort)subtraction;
this.Intermediate.Word = (ushort)subtraction;
this.F = SetBit(this.F, StatusBits.NF);
this.F = ClearBit(this.F, StatusBits.ZF, this.intermediate.Word);
this.F = ClearBit(this.F, StatusBits.ZF, this.Intermediate.Word);
this.F = SetBit(this.F, StatusBits.CF, subtraction & (int)Bits.Bit16);
this.F = AdjustHalfCarrySub(this.F, operand.High, value.High, this.intermediate.High);
this.F = AdjustXY(this.F, this.intermediate.High);
this.F = AdjustHalfCarrySub(this.F, operand.High, value.High, this.Intermediate.High);
this.F = AdjustXY(this.F, this.Intermediate.High);
var beforeNegative = operand.High & (byte)StatusBits.SF;
var valueNegative = value.High & (byte)StatusBits.SF;
var afterNegative = this.intermediate.High & (byte)StatusBits.SF;
var afterNegative = this.Intermediate.High & (byte)StatusBits.SF;
this.F = SetBit(this.F, StatusBits.SF, afterNegative);
this.F = AdjustOverflowSub(this.F, beforeNegative, valueNegative, afterNegative);
this.MEMPTR.Word = (ushort)(operand.Word + 1);
return this.intermediate.Word;
return this.Intermediate.Word;
}
private ushort ADC(Register16 operand, Register16 value)
{
this.Add(operand, value, this.F & (byte)StatusBits.CF); // Leaves result in intermediate anyway
this.F = ClearBit(this.F, StatusBits.ZF, this.intermediate.Word);
this.F = ClearBit(this.F, StatusBits.ZF, this.Intermediate.Word);
var beforeNegative = operand.High & (byte)StatusBits.SF;
var valueNegative = value.High & (byte)StatusBits.SF;
var afterNegative = this.intermediate.High & (byte)StatusBits.SF;
var afterNegative = this.Intermediate.High & (byte)StatusBits.SF;
this.F = SetBit(this.F, StatusBits.SF, afterNegative);
this.F = AdjustOverflowAdd(this.F, beforeNegative, valueNegative, afterNegative);
return this.intermediate.Word;
return this.Intermediate.Word;
}
private ushort Add(Register16 operand, Register16 value, int carry = 0)
{
var addition = operand.Word + value.Word + carry;
this.intermediate.Word = (ushort)addition;
this.Intermediate.Word = (ushort)addition;
this.F = ClearBit(this.F, StatusBits.NF);
this.F = SetBit(this.F, StatusBits.CF, addition & (int)Bits.Bit16);
this.F = AdjustHalfCarryAdd(this.F, operand.High, value.High, this.intermediate.High);
this.F = AdjustXY(this.F, this.intermediate.High);
this.F = AdjustHalfCarryAdd(this.F, operand.High, value.High, this.Intermediate.High);
this.F = AdjustXY(this.F, this.Intermediate.High);
this.MEMPTR.Word = (ushort)(operand.Word + 1);
return this.intermediate.Word;
return this.Intermediate.Word;
}
private byte Add(byte operand, byte value, int carry = 0)
{
this.intermediate.Word = (ushort)(operand + value + carry);
var result = this.intermediate.Low;
this.Intermediate.Word = (ushort)(operand + value + carry);
var result = this.Intermediate.Low;
this.F = AdjustHalfCarryAdd(this.F, operand, value, result);
this.F = AdjustOverflowAdd(this.F, operand, value, result);
this.F = ClearBit(this.F, StatusBits.NF);
this.F = SetBit(this.F, StatusBits.CF, this.intermediate.High & (byte)StatusBits.CF);
this.F = SetBit(this.F, StatusBits.CF, this.Intermediate.High & (byte)StatusBits.CF);
this.F = AdjustSZXY(this.F, result);
return result;
@@ -2104,8 +2104,8 @@ namespace EightBit
private void WritePort(byte port)
{
this.MEMPTR.Word = this.Bus.Address.Word = new Register16(port, this.A).Word;
this.Bus.Data = this.A;
this.MEMPTR.Low = this.Bus.Address.Low = port;
this.MEMPTR.High = this.Bus.Address.High = this.Bus.Data = this.A;
this.WritePort();
++this.MEMPTR.Low;
}
@@ -2122,7 +2122,8 @@ namespace EightBit
private byte ReadPort(byte port)
{
this.MEMPTR.Word = this.Bus.Address.Word = new Register16(port, this.A).Word;
this.MEMPTR.Low = this.Bus.Address.Low = port;
this.MEMPTR.High = this.Bus.Address.High = this.A;
++this.MEMPTR.Low;
return this.ReadPort();
}