Volume 2, Part 1: Itanium
®
Architecture-based Operating System Interaction Model with IA-32 Applications
2:245
EFLAG.iopl
13:12
IA-32 In/Out Privilege Level, controls accessibility by IA-32 IN/OUT instructions to the
I/O port space and permission to modify the IF-bit for Intel Itanium and IA-32
instructions. If PSR.cpl > IOPL, permission is denied for IA-32 IN/OUT instructions,
and modifications of EFLAG.if by either IA-32 or Intel Itanium instructions are ignored.
IOPL can only be modified by IA-32 or Intel Itanium instructions executing at privilege
level 0, otherwise modifications of this bit are silently ignored. This bit is supported in
both the IA-32 and Intel Itanium System Environments. See the
Intel
®
64 and IA-32
Architectures Software Developer’s Manual
for details on this bit.
EFLAG.nt
14
IA-32 Nested Task switch. In the IA-32 System Environment, indicates a nested task
flag when chaining interrupted and called IA-32 tasks. IA-32 task switches are not
directly supported in the Intel Itanium System Environment, since IRET, interruptions,
calls, and jumps through task gates are always intercepted. EFLAG.nt can be
modified by the POPF or POPFD instruction in both system environments.
Modification of EFLAG.nt by POPF and POPFD does not result in a System Flag
Intercept. See the
Intel
®
64 and IA-32 Architectures Software Developer’s
Manual
for details on this bit.
EFLAG.rf
16
IA-32 Resume Flag. In the Intel Itanium System Environment, when EFLAG.rf or
PSR.id is 1, code breakpoint faults are temporarily disabled for one IA-32 instruction,
so that IA-32 instructions can be restarted after a code breakpoint fault without
causing another code breakpoint fault. EFLAG.rf does not affect Intel Itanium
Instruction Debug faults. After the successful execution of each IA-32 instruction,
PSR.id and EFLAG.rf are cleared to zero. On entry into the IA-32 instruction set via
rfi
or
br.ia,
EFLAG.rf and PSR.id is not cleared until the successful completion of
the first (target) IA-32 instruction.
jmpe
clears the PSR.id and the EFLAG.rf bit.
EFLAG.rf is set to 1 if a repeat string sequence (REP MOVS, SCANS, CMPS, LODS,
STOS, INS, OUTS) takes an external interrupt, trap or fault before the final iteration.
EFLAG.rf and PSR.id are set to 0 after the last iteration. For all other cases, external
interrupts, faults, traps, and intercept conditions EFLAG.rf is unmodified.
The RF-bit can be modified by Intel Itanium instructions running at any privilege level.
IA-32 instructions cannot directly modify the RF-bit or PSR.id. Specifically, POPF
cannot modify the RF-bit and execution of IRET is always intercepted in the Intel
Itanium System Environment. See the
Intel
®
64 and IA-32 Architectures Software
Developer’s Manual
for details on this bit.
EFLAG.vm
17
IA-32 Virtual Mode 86. When 1, IA-32 instructions execute in the VM86 environment.
This bit can only be modified by IA-32 or Intel Itanium instructions executing at
privilege ring 0, otherwise modifications of this bit by Intel Itanium or IA-32
instructions is silently ignored. Itanium architecture-based software is responsible for
initializing the processor with the required VM86 register state before transferring to
IA-32 VM86 environment. This bit is supported in both the IA-32 and Intel Itanium
System Environments. See the
Intel
®
64 and IA-32 Architectures Software
Developer’s Manual
for complete details of the VM86 environment. Software must
ensure the processor is in IA-32 Protected Mode when setting the VM bit.
EFLAG.ac
18
IA-32 Alignment Check. In the Intel Itanium System Environment, IA-32 instructions
raise an IA_32_Exception(AlignmentCheck) fault if an unaligned reference is
performed and PSR.ac is 1 or (CFLG.am is 1 and EFLAG.ac is 1 and memory is
accessed at an effective privilege level of 3). Neither EFLAG.ac, CR0.am nor privilege
level affect alignment check faults for Intel Itanium instructions. See
“Memory Alignment” on page 2:263
for details on alignment conditions. This bit can
be modified by IA-32 and Intel Itanium instructions at any privilege level. Modification
of this bit by the POPF instructions results in an IA_32_Intercept(SystemFlag) trap.
See the
Intel
®
64 and IA-32 Architectures Software Developer’s Manual
for
details on this bit.
Table 10-3.
IA-32 EFLAG Field Definition (Continued)
EFLAG
a
Bits
Description
Содержание ITANIUM ARCHITECTURE - SOFTWARE DEVELOPERS VOLUME 3 REV 2.3
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Страница 11: ...x Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
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Страница 33: ...1 22 Volume 1 Part 1 Introduction to the Intel Itanium Architecture ...
Страница 57: ...1 46 Volume 1 Part 1 Execution Environment ...
Страница 147: ...1 136 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 149: ...1 138 Volume 1 Part 2 About the Optimization Guide ...
Страница 191: ...1 180 Volume 1 Part 2 Predication Control Flow and Instruction Stream ...
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Страница 249: ...2 1 Intel Itanium Architecture Software Developer s Manual Rev 2 3 Part I System Architecture Guide ...
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Страница 264: ...2 16 Volume 2 Part 1 Intel Itanium System Environment ...
Страница 380: ...2 132 Volume 2 Part 1 Interruptions ...
Страница 398: ...2 150 Volume 2 Part 1 Register Stack Engine ...
Страница 486: ...2 238 Volume 2 Part 1 IA 32 Interruption Vector Descriptions ...
Страница 749: ...2 501 Intel Itanium Architecture Software Developer s Manual Rev 2 3 Part II System Programmer s Guide ...
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Страница 754: ...2 506 Volume 2 Part 2 About the System Programmer s Guide ...
Страница 796: ...2 548 Volume 2 Part 2 Interruptions and Serialization ...
Страница 808: ...2 560 Volume 2 Part 2 Context Management ...
Страница 842: ...2 594 Volume 2 Part 2 Floating point System Software ...
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Страница 1191: ...3 292 Volume 3 Pseudo Code Functions Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 1295: ...3 396 Volume 3 Resource and Dependency Semantics ...
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Страница 1494: ...4 192 Volume 4 Base IA 32 Instruction Reference FWAIT Wait See entry for WAIT ...
Страница 1564: ...4 262 Volume 4 Base IA 32 Instruction Reference LES Load Full Pointer See entry for LDS LES LFS LGS LSS ...
Страница 1565: ...Volume 4 Base IA 32 Instruction Reference 4 263 LFS Load Full Pointer See entry for LDS LES LFS LGS LSS ...
Страница 1568: ...4 266 Volume 4 Base IA 32 Instruction Reference LGS Load Full Pointer See entry for LDS LES LFS LGS LSS ...
Страница 1583: ...Volume 4 Base IA 32 Instruction Reference 4 281 LSS Load Full Pointer See entry for LDS LES LFS LGS LSS ...
Страница 1647: ...Volume 4 Base IA 32 Instruction Reference 4 345 ROL ROR Rotate See entry for RCL RCR ROL ROR ...
Страница 1663: ...Volume 4 Base IA 32 Instruction Reference 4 361 SHL SHR Shift Instructions See entry for SAL SAR SHL SHR ...
Страница 1668: ...4 366 Volume 4 Base IA 32 Instruction Reference SIDT Store Interrupt Descriptor Table Register See entry for SGDT SIDT ...
Страница 1884: ...4 582 Volume 4 IA 32 SSE Instruction Reference ...
Страница 1885: ...Index Intel Itanium Architecture Software Developer s Manual Rev 2 3 Index ...
Страница 1886: ...Index Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 1898: ...INDEX Index 12 Index for Volumes 1 2 3 and 4 ...