private void AddHandler(U8Cmd cmd)
{
// This instruction adds the sign-extended signed8 to the contetnts of the stack
// poionter and stores the result in the stack pointer.
// bit 7 in signed8 is interpreted as the sign bit, so signed8 is an integer
// quantity between -128 and +127.
if(U8Decoder.isNegative7Bit((byte)cmd.Op2) == 1)
StackPtr -= U8Decoder.ABS7Bit((byte)cmd.Op2);
else
StackPtr += U8Decoder.ABS7Bit((byte)cmd.Op2);
}
private void AddSpO(U8Cmd cmd)
{
// This inst adds the sign-extended signed8 to the contents of the stack pointer
// and stores the result in the stack pointer
if (U8Decoder.isNegative7Bit((byte)cmd.Op1) == 1)
{
this.Registers.SP -= U8Decoder.ABS7Bit((byte)cmd.Op1); // TODO: verify, may need Op2!!!
}
else
{
this.Registers.SP += U8Decoder.ABS7Bit((byte)cmd.Op1);
}
this.Registers.PC += 2;
}
private void AddERegO(U8Cmd cmd)
{
// This inst adds the sign-extended immediate vlaue to the contents of the specified
// word-sized register and stores the result in the register.
var sum = 0;
if (U8Decoder.isNegative7Bit((byte)cmd.Op2) == 1)
{
sum = this.Registers.GetERegisterByIndex((byte)cmd.Op1) - U8Decoder.ABS7Bit((byte)cmd.Op2);
}
else
{
sum = this.Registers.GetERegisterByIndex((byte)cmd.Op1) + U8Decoder.ABS7Bit((byte)cmd.Op2);
}
this.Registers.SetERegisterByIndex((byte)cmd.Op1, (ushort)sum);
this.Registers.PC += 2;
// TODO: this.Registers.PSW.C
this.Registers.PSW.Z = sum == 0;
// TODO: this.Registers.PSW.S = TRACK TOP BIT OF RESULT
this.Registers.PSW.OV = sum > ushort.MaxValue;
// TODO: this.Registers.PSW.HC = idk ;/
}
