A <- A | (IY+d)
OR
(IY+d)
| b7 | b6 | b5 | b4 | b3 | b2 | b1 | b0 | |
|---|---|---|---|---|---|---|---|---|
| 1 | 1 | 1 | 1 | 1 | 1 | 0 | 1 | $FD |
| 1 | 0 | 1 | 1 | 0 | 1 | 1 | 0 | $B6 |
| d | ||||||||
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. A logical OR operation is performed between the contents of this address and the contents in the Accumulator, 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 reset. |
| P/V | is reset if overflow, otherwise it is reset |
| N | is reset. |
| C | is reset. |
If the Accumulator contains $12 (0001 0010), Index Register IY contains $1000, and memory location $1005 contains $48 (0100 1000), then upon the execution of
OR (IY+$05)
the Accumulator contains $5A (0101 1010).