Volume 4: Base IA-32 Instruction Reference
4:267
LLDT—Load Local Descriptor Table Register
Description
Loads the source operand into the segment selector field of the local descriptor table
register (LDTR). The source operand (a general-purpose register or a memory location)
contains a segment selector that points to a local descriptor table (LDT). After the
segment selector is loaded in the LDTR, the processor uses to segment selector to
locate the segment descriptor for the LDT in the global descriptor table (GDT). It then
loads the segment limit and base address for the LDT from the segment descriptor into
the LDTR. The segment registers DS, ES, SS, FS, GS, and CS are not affected by this
instruction, nor is the LDTR field in the task state segment (TSS) for the current task.
If the source operand is 0, the LDTR is marked invalid and all references to descriptors
in the LDT (except by the LAR, VERR, VERW or LSL instructions) cause a general
protection exception (#GP).
The operand-size attribute has no effect on this instruction.
The LLDT instruction is provided for use in operating-system software; it should not be
used in application programs. Also, this instruction can only be executed in protected
mode.
Operation
IF Itanium System Environment THEN IA-32_Intercept(INST,LLDT);
IF SRC(Offset) > descriptor table limit THEN #GP(segment selector); FI;
Read segment descriptor;
IF SegmentDescriptor(Type)
LDT THEN #GP(segment selector); FI;
IF segment descriptor is not present THEN #NP(segment selector);
LDTR(SegmentSelector)
SRC;
LDTR(SegmentDescriptor)
GDTSegmentDescriptor;
Flags Affected
None.
Additional Itanium System Environment Exceptions
IA-32_Intercept
Instruction Intercept
Protected Mode Exceptions
#GP(0)
If the current privilege level is not 0.
If a memory operand effective address is outside the CS, DS, ES, FS,
or GS segment limit.
If the DS, ES, FS, or GS register contains a null segment selector.
Opcode
Instruction
Description
0F 00 /2
LLDT
r/m16
Load segment selector
r/m16
into LDTR
Summary of Contents for ITANIUM ARCHITECTURE - SOFTWARE DEVELOPERS VOLUME 3 REV 2.3
Page 1: ......
Page 11: ...x Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Page 13: ...1 2 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Page 33: ...1 22 Volume 1 Part 1 Introduction to the Intel Itanium Architecture ...
Page 57: ...1 46 Volume 1 Part 1 Execution Environment ...
Page 147: ...1 136 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Page 149: ...1 138 Volume 1 Part 2 About the Optimization Guide ...
Page 191: ...1 180 Volume 1 Part 2 Predication Control Flow and Instruction Stream ...
Page 230: ......
Page 248: ...236 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Page 250: ...2 2 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Page 264: ...2 16 Volume 2 Part 1 Intel Itanium System Environment ...
Page 380: ...2 132 Volume 2 Part 1 Interruptions ...
Page 398: ...2 150 Volume 2 Part 1 Register Stack Engine ...
Page 486: ...2 238 Volume 2 Part 1 IA 32 Interruption Vector Descriptions ...
Page 750: ...2 502 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Page 754: ...2 506 Volume 2 Part 2 About the System Programmer s Guide ...
Page 796: ...2 548 Volume 2 Part 2 Interruptions and Serialization ...
Page 808: ...2 560 Volume 2 Part 2 Context Management ...
Page 842: ...2 594 Volume 2 Part 2 Floating point System Software ...
Page 850: ...2 602 Volume 2 Part 2 IA 32 Application Support ...
Page 862: ...2 614 Volume 2 Part 2 External Interrupt Architecture ...
Page 870: ...2 622 Volume 2 Part 2 Performance Monitoring Support ...
Page 891: ......
Page 1099: ...3 200 Volume 3 Instruction Reference padd Interruptions Illegal Operation fault ...
Page 1295: ...3 396 Volume 3 Resource and Dependency Semantics ...
Page 1296: ......
Page 1302: ...402 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Page 1494: ...4 192 Volume 4 Base IA 32 Instruction Reference FWAIT Wait See entry for WAIT ...
Page 1647: ...Volume 4 Base IA 32 Instruction Reference 4 345 ROL ROR Rotate See entry for RCL RCR ROL ROR ...
Page 1884: ...4 582 Volume 4 IA 32 SSE Instruction Reference ...
Page 1885: ...Index Intel Itanium Architecture Software Developer s Manual Rev 2 3 Index ...
Page 1886: ...Index Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Page 1898: ...INDEX Index 12 Index for Volumes 1 2 3 and 4 ...