6502/EightBitNet
1
0
Fork 0
mirror of https://github.com/MoleskiCoder/EightBitNet.git synced 2024-06-02 16:41:33 +00:00
Code Issues Projects Releases Wiki Activity

Some minor MC6809 tidying up

Browse Source 
Signed-off-by: Adrian Conlon <adrian.conlon@gmail.com>
This commit is contained in:
Adrian Conlon 2019-04-21 19:54:26 +01:00
parent 2a4a067fe4
commit 6e781ced44
1 changed files with 51 additions and 74 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

125
MC6809/MC6809.cs
View File

@ -5,16 +5,16 @@
// Uses some information from:
// http://www.cpu-world.com/Arch/6809.html
// |---------------|-----------------------------------|
// | MPU State | |
// |_______________| MPU State Definition |
// | BA | BS | |
// |_______|_______|___________________________________|
// | 0 | 0 | Normal (running) |
// | 0 | 1 | Interrupt or RESET Acknowledge |
// | 1 | 0 | SYNC Acknowledge |
// | 1 | 1 | HALT Acknowledge |
// |-------|-------|-----------------------------------|
// |---------------|-----------------------------------|
// | MPU State | |
// |_______________| MPU State Definition |
// | BA | BS | |
// |_______|_______|___________________________________|
// | 0 | 0 | Normal (running) |
// | 0 | 1 | Interrupt or RESET Acknowledge |
// | 1 | 0 | SYNC Acknowledge |
// | 1 | 1 | HALT Acknowledge |
// |-------|-------|-----------------------------------|
public sealed class MC6809 : BigEndianProcessor
{
@ -413,24 +413,16 @@
private void PushS(byte value) => this.Push(this.S, value);
//private void PushU(byte value) => this.Push(this.U, value);
private void PushWord(Register16 stack, Register16 value)
{
this.Push(stack, value.Low);
this.Push(stack, value.High);
}
//private void PushWordS(Register16 value) => this.PushWord(this.S, value);
//private void PushWordU(Register16 value) => this.PushWord(this.U, value);
private byte Pop(Register16 stack) => this.BusRead(stack++);
private byte PopS() => this.Pop(this.S);
//private byte PopU() => this.Pop(this.U);
private Register16 PopWord(Register16 stack)
{
var high = this.Pop(stack);
@ -438,16 +430,12 @@
return new Register16(low, high);
}
//private Register16 PopWordS() => this.PopWord(this.S);
//private Register16 PopWordU() => this.PopWord(this.U);
private Register16 RR(int which)
{
switch (which) {
case 0b00:
return this.X;
case 0b01:
switch (which) {
case 0b00:
return this.X;
case 0b01:
return this.Y;
case 0b10:
return this.U;
@ -455,7 +443,7 @@
return this.S;
default:
throw new ArgumentOutOfRangeException("which", which, "Which does not specify a valid register");
}
}
}
private Register16 Address_relative_byte() => new Register16(this.PC.Word + (sbyte)this.FetchByte());
@ -575,8 +563,6 @@
private byte AdjustNegative(ushort datum) => SetFlag(this.CC, StatusBits.NF, datum & (ushort)Bits.Bit15);
//private void AdjustNegative(Register16 datum) => this.AdjustNegative(datum.Word);
private byte AdjustNZ(byte datum)
{
this.CC = this.AdjustZero(datum);
@ -597,12 +583,6 @@
private byte AdjustCarry(Register16 datum) => this.AdjustCarry(datum.Word);
//private void AdjustBorrow(ushort datum) => ClearFlag(this.CC, StatusBits.CF, datum & (ushort)Bits.Bit8); // 8-bit subtraction
//private void AdjustBorrow(uint datum) => ClearFlag(this.CC, StatusBits.CF, (int)(datum & (uint)Bits.Bit16)); // 16-bit subtraction
//private void AdjustBorrow(Register16 datum) => this.AdjustBorrow(datum.Word);
private byte AdjustOverflow(byte before, byte data, Register16 after)
{
var lowAfter = after.Low;
@ -617,8 +597,6 @@
return SetFlag(this.CC, StatusBits.VF, (before ^ data ^ lowAfter ^ (highAfter << 15)) & (int)Bits.Bit15);
}
//private void AdjustOverflow(Register16 before, Register16 data, Register16 after) => this.AdjustOverflow(before.Word, data.Word, after.Word);
private byte AdjustHalfCarry(byte before, byte data, byte after) => SetFlag(this.CC, StatusBits.HF, (before ^ data ^ after) & (int)Bits.Bit4);
private byte AdjustAddition(byte before, byte data, Register16 after)
@ -665,13 +643,6 @@
return data;
}
//private ushort Through(ushort data)
//{
// ClearFlag(this.CC, StatusBits.VF);
// this.AdjustNZ(data);
// return data;
//}
private Register16 Through(Register16 data)
{
this.CC = ClearFlag(this.CC, StatusBits.VF);
@ -681,14 +652,10 @@
private byte LD(byte data) => this.Through(data);
//private ushort LD(ushort data) => this.Through(data);
private Register16 LD(Register16 data) => this.Through(data);
private byte ST(byte data) => this.Through(data);
//private ushort ST(ushort data) => this.Through(data);
private Register16 ST(Register16 data) => this.Through(data);
private void Jump(Register16 destination) => this.Jump(destination.Word);
@ -701,14 +668,10 @@
}
return condition;
}
}
private bool Branch(Register16 destination, bool condition) => this.Branch(destination.Word, condition);
//private void Branch(ushort destination, int condition) => this.Branch(destination, condition != 0);
//private void Branch(Register16 destination, int condition) => this.Branch(destination.Word, condition);
private void BranchShort(bool condition) => this.Branch(this.Address_relative_byte(), condition);
private void BranchLong(bool condition)
@ -754,22 +717,22 @@
Register16 ReferenceTransfer16(int specifier)
{
switch (specifier) {
case 0b0000:
return this.D;
case 0b0001:
return this.X;
case 0b0010:
return this.Y;
case 0b0011:
return this.U;
case 0b0100:
return this.S;
case 0b0101:
return this.PC;
default:
switch (specifier) {
case 0b0000:
return this.D;
case 0b0001:
return this.X;
case 0b0010:
return this.Y;
case 0b0011:
return this.U;
case 0b0100:
return this.S;
case 0b0101:
return this.PC;
default:
throw new ArgumentOutOfRangeException("specifier", specifier, "Invalid specifier");
}
}
}
private void ExecuteUnprefixed()
@ -1329,10 +1292,17 @@
private void EXG(byte data)
{
var specifier1 = Chip.HighNibble(data);
var specifier2 = Chip.LowNibble(data);
var type1 = specifier1 & (int)Bits.Bit3; // transfer type, part 1
var type8 = (specifier1 & (int)Bits.Bit3) == 0; // 8 bit exchange?
if (type8)
var specifier2 = Chip.LowNibble(data);
var type2 = specifier2 & (int)Bits.Bit3; // transfer type, part 2
if (type1 != type2)
{
throw new ArgumentOutOfRangeException("data", data, "Type specifications do not match");
}
if (type1 == 0)
{
ref var register1 = ref this.ReferenceTransfer8(specifier1);
ref var register2 = ref this.ReferenceTransfer8(specifier2);
@ -1559,10 +1529,17 @@
private void TFR(byte data)
{
var specifier1 = Chip.HighNibble(data);
var specifier2 = Chip.LowNibble(data);
var type1 = specifier1 & (int)Bits.Bit3; // transfer type, part 1
var type8 = (specifier1 & (int)Bits.Bit3) == 0; // 8 bit transfer?
if (type8)
var specifier2 = Chip.LowNibble(data);
var type2 = specifier2 & (int)Bits.Bit3; // transfer type, part 2
if (type1 != type2)
{
throw new ArgumentOutOfRangeException("data", data, "Type specifications do not match");
}
if (type1 == 0)
{
ref var register1 = ref this.ReferenceTransfer8(specifier1);
ref var register2 = ref this.ReferenceTransfer8(specifier2);