DR805x Instructions set details
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3.33. RETI
Function:
Return from interrupt
Description: RETI pops the high and low-order bytes of the PC successively from
the stack, and restores the interrupt logic to accept additional interrupts
at the same priority level as the one just processed. The stack pointer is
left decremented by two. No other registers are affected; the PSW is not
automatically restored to its pre-interrupt status. Program execution
continues at the resulting address, which is generally the instruction
immediately after the point at which the interrupt request was detected.
If a lower or same-level interrupt is pending when the RETI instruction is
executed, that one instruction will be executed before the pending
interrupt is processed.
Operation:
(PC15-8) ← ((SP))
(SP) ← (SP) - 1
(PC7-0) ← ((SP))
(SP)
← (SP) - 1
Bytes:
Cycles:
1
4
Encoding:
0
0
1
1
0
0
1
0
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