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Volume 4: Base IA-32 Instruction Reference
4:61
CLI—Clear Interrupt Flag
Description
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.
In the Itanium System Environment, external interrupts are enabled
for IA-32 instructions if PSR.i and (~CFLG.if or EFLAG.if) is 1 and for Itanium
instructions if PSR.i is 1.
The following decision table indicates the action of the CLI instruction (bottom of the
table) depending on the processor’s mode of operating and the CPL and IOPL of the
currently running program or procedure (top of the table).
Notes:
XDon't care.
NAction in column 1 not taken.
YAction in column 1 taken.
Operation
OLD_IF <- IF;
IF PE = 0 (* Executing in real-address mode *)
THEN
IF
0;
ELSE
IF VM = 0 (* Executing in protected mode *)
THEN
IF CR4.PVI = 1
THEN
IF CPL = 3
THEN
IF IOPL<3
THEN VIF <- 0;
ELSE IF <- 0;
FI;
ELSE (*CPL < 3*)
IF IOPL < CPL
THEN #GP(0);
ELSE IF <- 0;
Opcode
Instruction
Description
FA
CLI
Clear interrupt flag; interrupts disabled when interrupt flag
cleared
PE =
0
1
1
1
1
VM =
X
0
X
0
1
CPL
X
IOPL
X
> IOPL
X
IOPL
X
X
3
X
< 3
IF
0
Y
Y
Y
N
N
#GP(0)
N
N
N
Y
Y
Summary of Contents for ITANIUM ARCHITECTURE
Page 1: ......
Page 7: ...402 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Page 199: ...4 192 Volume 4 Base IA 32 Instruction Reference FWAIT Wait See entry for WAIT ...
Page 352: ...Volume 4 Base IA 32 Instruction Reference 4 345 ROL ROR Rotate See entry for RCL RCR ROL ROR ...
Page 589: ...4 582 Volume 4 IA 32 SSE Instruction Reference ...
Page 590: ...Index Intel Itanium Architecture Software Developer s Manual Rev 2 3 Index ...
Page 591: ...Index Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Page 603: ...INDEX Index 12 Index for Volumes 1 2 3 and 4 ...
Page 604: ......