A <- A - (IY+d) - CY
The contents of the Index (register pair IY) Register is added to a two's complement displacement d to point to an address in memory. The contents of this address along with the Carry Flag (C in the F Register) is then subtracted from the contents of the Accumulator and the result is stored in the Accumulator.
|S||is set if result is negative, otherwise it is reset.|
|Z||is set if result is 0, otherwise it is reset.|
|H||is set if borrow from bit 4, otherwise it is reset.|
|P/V||is set if overflow, otherwise it is reset|
|C||is set if borrow, otherwise it is reset.|
If the Accumulator contains $22, Index Register IY contains $1000, the Carry Flag is set and memory location $1005 contains $11, then upon the execution of
the Accumulator contains $10.