title: Borrow during subtracting operation (sbc asm instruction) on 6502?
body: <p>When the borrow (i.e. carry flag is cleared) happens during subtracting operation (sbc asm instruction) on 6502 used by NES? Is it each time the result is negative (-1 to -128)?</p>
  
  <p>Many thanks!
  Thanks
  STeN</p>