RETN |
Return from non-maskable interrupt. |
Function: |
PClow
(SP); PChigh
(SP + 1); SP
SP + 2; IFF1
IFF2 |
Format: |
|
byte 1: ED |
|
|
byte 2: 45 |
Description: |
The program counter is popped off the stack as described for the POP instructions. Then the contents of the IFF2 (storage flip-flop) is copied back into the IFF1 to restore the state of the interrupt flag before the non-maskable interrupt. |
Data Flow: |
|
Timing: |
4 M cycles; 14 T states: 7 usec @ 2 MHz |
Addressing Mode: |
indirect |
Flags: |
|
(no effect) |
Example: |
RETN |
OBJECT CODE |
Before: |
After: |
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