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Joseph Hebert
01/11/06 09:12
Read: 580 times
Okemah, Ok
United States

#107052 - CY AC and OC
Responding to: Indika Herath's previous message
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.

List of 7 messages in thread
Help about ADD/ADDC in a VB project      Indika Herath      01/11/06 08:52      
   all answers are in "the bible"      Erik Malund      01/11/06 09:04      
   CY AC and OC      Joseph Hebert      01/11/06 09:12      
      Reply about ADD/ADDC in a VB project      Indika Herath      01/13/06 08:29      
         AGAIN: why reinvent the wheel?      Erik Malund      01/13/06 09:12      
   did you consider      Erik Malund      01/11/06 09:27      
      He's writing a simulator?      Joseph Hebert      01/11/06 09:53      

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