Hi Indika,

I am not familiar with VB, but I can tell you that you seem to be a bit confused about CY, AC and OV. These are not functions which alter the states of flags. These are the names of flags, which is to say they are bits in the Program Status Word (PSW) register. CY is the CarrY flag (PSW bit 7), AC is the Auxillary Carry flag (PSW bit 6), and OV is the OVerflow flag (PSW bit 2). These are set by hardware, under specific conditions which can be instruction dependent. I don't know how you would manipulate them directly in VB, but in assembler you would simply set and clear them by name (assuming the names are defined) or by address.