Volume 2, Part 2: Interruptions and Serialization
2:539
instruction address translation is disabled, the IVA register should contain the physical
address of the base of the IVT. Software must further ensure that instruction and
memory references from low-level interruption handlers do not generate additional
interruptions until enough state has been saved and interruption collection can be
re-enabled.
There are many more interruptions than there are interruption vectors in the IVT. As
specified in
Section 5.6, “Interruption Priorities”
there is a many-to-one relationship
between interruptions and interruption vectors. The interruptions that share a common
interruption vector (and hence, the code for an interruption handler) can determine
which interruption occurred by reading the Interruption Status Register (ISR) control
register. See
Chapter 8, “Interruption Vector Descriptions”
Interruption Vector Descriptions”
for details of the specific ISR settings for each unique
interruption.
3.3
Interruption Handlers
3.3.1
Execution Environment
As defined in
Section 5.5, “IVA-based Interruption Handling” on page 2:101
processor automatically clears the PSR.i and PSR.ic bits when an interruption is
delivered. This disables external interrupts and interrupt state collection, respectively.
PMI delivery is also disabled while PSR.ic is 0; other PAL-based interruptions can be
delivered at any point during the execution of the interruption handler, regardless of the
state of PSR.i and PSR.ic.
In addition to clearing the PSR.i and PSR.ic bits, the processor also automatically clears
the PSR.bn bit when an interruption is delivered, switching to bank 0 of general
registers GR16 - GR31. This provides the interruption handler with its own set of
registers which can be used without spilling any of the interrupted context’s register
state, effectively saving GR16 - GR31 of the interrupted context. (This assumes PSR.bn
is 1 at the time of interruption; see
Section 3.4.3, “Nested Interruptions” on
for how to deal with the case where PSR.bn is 0 at the time of interruption.)
As specified in
Section 3.3.7, “Banked General Registers” on page 2:42
, GR24 - GR31
of bank 0
should not be used while PSR.ic is 1. By firmware convention, PAL-based
interruption handlers may use these registers without preserving their values when
PSR.ic is 1. When PSR.ic is 0, software may safely use GR24 - GR31 of bank 0 as
scratch register.
Several other PSR bits and the RSE.CFLE are modified by the hardware when an
interruption is delivered.
summarizes the execution environment that
interruption handlers operate in, and what each PSR bit and the RSE.CFLE values mean
for the interruption handler.
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 ...
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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 ...