Volume 2, Part 1: Itanium
®
Architecture-based Operating System Interaction Model with IA-32 Applications
2:277
10.9.2
IA-32 Numeric Exception Model
IA-32 numeric instructions follow the IA-32 delayed floating-point exception model.
Specifically IA-32 numeric exceptions are held pending until the next IA-32 numeric or
MMX technology instruction as defined in the
Intel
®
64 and IA-32 Architectures
Software Developer’s Manual
. Numeric faults generated on SSE instructions are
reported precisely on the faulting SSE instruction. SSE instructions do NOT trigger the
report of pending IA-32 numeric exceptions.
For voluntary transitions out of the IA-32 instruction, an implicit FWAIT operation is
performed by the
jmpe
instruction to ensure all pending numeric exceptions are
reported. For involuntary transitions out of the IA-32 instruction set (external
interruptions, TLB faults, exceptions, etc.) the processor does not perform a FWAIT
operation. However, every IA-32 numeric instruction that generates a pending numeric
exception loads the application registers FSR, FIR, and FDR with the IA-32
floating-point state on the instruction that generating the exception. This state contains
information defined by the IA-32 FSTENV and FLDENV instructions. During a process
context switch, the operating system must save and restore FSR, FIR, and FDR
(effectively performing an FSTENV and FLDENV) to ensure numeric exceptions are
correctly reported across a process switch.
10.10
Processor Bus Considerations for IA-32
Application Support
The section briefly discusses bus and platform considerations when supporting IA-32
applications in the Itanium System Environment.
Itanium architecture-based code does not assert the SPLCK and LOCK pins. The LOCK
pin is used by IA-32 code to signal an external atomic bus transaction for which
atomicity cannot be enforced within the processor's caches, whereas, SPLCK indicates if
an unaligned external bus lock requires a split lock operation and hence several bus
IA_32_Intercept(Inst)
0
InterceptCode
Intercept for unimplemented, illegal
or privileged IA-32 opcodes.
IA_32_Intercept(Gate)
1
TrapCode
Intercept for control transfers
through a Call Gate, Task gate or
Task Segment.
IA_32_Intercept(SystemFlag)
2
TrapCode
Intercept for modification of system
flag values.
IA_32_Intercept(Lock)
4
0
IA-32 semaphore operation
requires an external bus lock when
DCR.lc is 1.
3,5-25
5
--
Intel reserved
a. The IA-32 Error Code is defined as a Selector Index, and TI, IDT and EXT bits are set based on the
exception. See
Intel
®
64 and IA-32 Architectures Software Developer’s Manual
for the complete
definition.
Table 10-9.
IA-32 Interruption Summary (Continued)
IA-32
Vector
Itanium
®
Architecture-based
Interruption Handler
ISR
Vector
ISR
Code
Description
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 ...
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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 ...