Interrupt Ordering - Motorola MPC823e Reference Manual

The PowerPC Core

6.3.8 Interrupt Ordering

There are two main types of interrupts:
• Instruction-related interrupts
• Asynchronous interrupts
Instruction-related exceptions (interrupt causes) are detected while the instruction is in
various stages of being processed by the core. Exceptions found early in instruction
processing preclude detection of further exceptions. This earlier interrupt will eventually be
taken. If more than one instruction in the pipeline causes an exception, only the first
exception is taken and causes an interrupt. The remaining instruction-induced exceptions
are ignored. The following table lists the instruction-related interrupts in the order of
detection within the instruction processing.
Table 6-5. Instruction-Related Interrupt Detection Order
NUMBER
1 Trace
2 Implementation Dependent Instruction TLB
Miss
3 Implementation Dependent Instruction TLB
Error
4 Machine Check Interrupt
5 Debug I- Breakpoint
6 Implementation Dependent Software Emulation
Interrupt
1 Floating-Point Unavailable
2
Privileged Instruction
7
Alignment Interrupt
System Call Interrupt
Trap
8 Implementation Dependent Data TLB Miss
9 Implementation Dependent Data TLB Error
10 Machine Check Interrupt
11 Debug L- Breakpoint
NOTES: 1. The trace mechanism is implemented by letting one instruction go as if no trace is enabled and
trapping the second instruction. This, of course, refers to this second instruction.
2. Exclusive for any one instruction.
6-14
INTERRUPT TYPE
MPC823e REFERENCE MANUAL
CAUSE
1
Trace Bit Asserted
Instruction Memory Management Unit TLB Miss
Instruction Memory Management Unit
Protection / Translation Error
Fetch Error
Match Detection
Attempt to Invoke Unimplemented Feature
Attempt to is Made to Execute Floating-Point
Instruction and MSR =0
FP
Attempt to Execute Privileged Instruction in
Problem Mode
Load/Store Checking
SC Instruction
Trap Instruction
Data Memory Management Unit TLB Miss
Data Memory Management Unit TLB Protection/
Translation Error
Load or Store Access Error
Match Detection
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