Returning from a vectored interrupt, Interrupt vectoring example – Zilog Z16F2810 User Manual
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Interrupts
UM018809-0611
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ZNEO
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CPU Core
User Manual
Returning From a Vectored Interrupt
If no interrupts are pending or the
CIRQE
) is 0, executing
the Interrupt Return (IRET) instruction at the end of an interrupt service routine results in
the following operations:
1. Pop PC[31:24] from the stack.
2. Pop PC[23:16] from the stack.
3. Pop PC[15:8] from the stack.
4. Pop PC[7:0] from the stack.
5. Increment SP by 1 (so SP alignment is not changed).
Figure 11. Interrupt Vectoring Example
Memory
Interrupt Vector Quad
Interrupt
Vector
Table
Interrupt Service
Routine First
Vector[23:16] = 23H
Vector[15:8] = 45H
0023_4567H
0000_0014H
0000_0015H
Vector[7:0] = 67H
0000_0016H
0000_0017H
Vector[31:24] = 00H
Quad Base Address
Address
Instruction