Intel IA-32 Manuale Utente Scaricare il pdf (Pagina 204)

100

101

5-28 Vol. 3A

INTERRUPT AND EXCEPTION HANDLING

Interrupt 1—Debug Exception (#DB)

Exception Class Trap or Fault. The exception handler can distinguish between traps or

faults by examining the contents of DR6 and the other debug registers.

Description

Indicates that one or more of several debug-exception conditions has been detected. Whether the

exception is a fault or a trap depends on the condition (see Table 5-3). See Chapter 18, “Debug-

ging and Performance Monitoring,” for detailed information about the debug exceptions.

Exception Error Code

None. An exception handler can examine the debug registers to determine which condition

caused the exception.

Saved Instruction Pointer

Fault — Saved contents of CS and EIP registers point to the instruction that generated the

exception.

Trap — Saved contents of CS and EIP registers point to the instruction following the instruction

that generated the exception.

Program State Change

Fault — A program-state change does not accompany the debug exception, because the excep-

tion occurs before the faulting instruction is executed. The program can resume normal execu-

tion upon returning from the debug exception handler.

Trap — A program-state change does accompany the debug exception, because the instruction

or task switch being executed is allowed to complete before the exception is generated.

However, the new state of the program is not corrupted and execution of the program can

continue reliably.

Table 5-3. Debug Exception Conditions and Corresponding Exception Classes

Exception Condition Exception Class

Instruction fetch breakpoint Fault

Data read or write breakpoint Trap

I/O read or write breakpoint Trap

General detect condition (in conjunction with in-circuit emulation) Fault

Single-step Trap

Task-switch Trap

1 2 ... 199 200 201 202 203 204 205 206 207 208 209 ... 635 636

Commenti su questo manuale

Nessun commento

Intel IA-32 Manuale Utente Pagina 204

Commenti su questo manuale

Prodotti e manuali riguardandi Accessori per computer Intel IA-32