모두의 코드
CLI (Intel x86/64 assembly instruction)
CLI
Clear Interrupt Flag
참고 사항
아래 표를 해석하는 방법은 x86-64 명령어 레퍼런스 읽는 법 글을 참조하시기 바랍니다.
Opcode | Instruction | Op/ | 64-bit | Compat/ | Description |
|---|---|---|---|---|---|
FA | NP | Valid | Valid | Clear interrupt flag; interrupts disabled when interrupt flag cleared. |
Instruction Operand Encoding
Op/En | Operand 1 | Operand 2 | Operand 3 | Operand 4 |
|---|---|---|---|---|
NP | NA | NA | NA | NA |
Description
If protected-mode virtual interrupts are not enabled, CLI clears the IF flag in the EFLAGS register. No other flags are affected. Clearing the IF flag causes the processor to ignore maskable external interrupts. The IF flag and the CLI and STI instruction have no affect on the generation of exceptions and NMI interrupts.
When protected-mode virtual interrupts are enabled, CPL is 3, and IOPL is less than 3; CLI clears the VIF flag in the EFLAGS register, leaving IF unaffected. Table 3-7 indicates the action of the CLI instruction depending on the processor operating mode and the CPL/IOPL of the running program or procedure.
Operation is the same in all modes.
Table 3-7. Decision Table for CLI Results
PE | VM | IOPL | CPL | PVI | VIP | VME | CLI Result |
|---|---|---|---|---|---|---|---|
0 | X | X | X | X | X | X | IF = 0 |
1 | 0 | >= CPL | X | X | X | X | IF = 0 |
1 | 0 | < CPL | 3 | 1 | X | X | VIF = 0 |
1 | 0 | < CPL | < 3 | X | X | X | GP Fault |
1 | 0 | < CPL | X | 0 | X | X | GP Fault |
1 | 1 | 3 | X | X | X | X | IF = 0 |
1 | 1 | < 3 | X | X | X | 1 | VIF = 0 |
1 | 1 | < 3 | X | X | X | 0 | GP Fault |
* X = This setting has no impact
Operation
IF PE = 0
THEN
IF <- 0; (* Reset Interrupt Flag *)
ELSE
IF VM = 0;
THEN
IF IOPL >= CPL
THEN
IF <- 0; (* Reset Interrupt Flag *)
ELSE
IF ((IOPL < CPL) and (CPL = 3) and (PVI = 1))
THEN
VIF <- 0; (* Reset Virtual Interrupt Flag *)
ELSE
#GP(0);
FI;
FI;
ELSE (* VM = 1 *)
IF IOPL = 3
THEN
IF <- 0; (* Reset Interrupt Flag *)
ELSE
IF (IOPL < 3) AND (VME = 1)
THEN
VIF <- 0; (* Reset Virtual Interrupt Flag *)
ELSE
#GP(0);
FI;
FI;
FI;
FI;
Flags Affected
If protected-mode virtual interrupts are not enabled, IF is set to 0 if the CPL is equal to or less than the IOPL; other-wise, it is not affected. Other flags are unaffected.
When protected-mode virtual interrupts are enabled, CPL is 3, and IOPL is less than 3; CLI clears the VIF flag in the EFLAGS register, leaving IF unaffected. Other flags are unaffected.
Protected Mode Exceptions
#GP(0)
If the CPL is greater (has less privilege) than the IOPL of the current program or procedure.
#UD
If the LOCK prefix is used.
Real-Address Mode Exceptions
#UD
If the LOCK prefix is used.
Virtual-8086 Mode Exceptions
#GP(0)
If the CPL is greater (has less privilege) than the IOPL of the current program or procedure.
#UD
If the LOCK prefix is used.
Compatibility Mode Exceptions
Same exceptions as in protected mode.
64-Bit Mode Exceptions
#GP(0)
If the CPL is greater (has less privilege) than the IOPL of the current program or procedure.
#UD
If the LOCK prefix is used.
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