2:88
Volume 2, Part 1: Addressing and Protection
undefined behavior; when changing an existing page from speculative to
non-speculative (or vice-versa), software should ensure that any ALAT entries
corresponding to that page are invalidated.
Limited speculation pages behave like non-speculative pages with respect to
speculative advanced loads, and behave like speculative pages with respect to all other
advanced and/or check loads.
describes the ALAT behavior of advanced and check loads for the different
speculation memory attributes.
4.4.11
Memory Attribute Transition
If software modifies the memory attributes for a page, it must perform explicit actions
to ensure that subsequent reads and writes using the new attribute will be coherent
with prior reads and writes that were performed with the old attribute. Processors may
have separate buffers for coalescing, uncacheable and cacheable references, and these
buffers need not be coherent with each other.
4.4.11.1
Virtual Addressing Memory Attribute Transition
To change a virtually-addressed page from one attribute to another, software must
perform the following sequence. (The address of the page whose attribute is being
modified is referred to as “X”).
Note:
This sequence is ONLY required if the new mapping and the old mapping do not
have the same memory attribute.
On the processor initiating the transition, perform the following steps 1-3:
1. PTE[X].p = 0 // Mark page as not present
This prevents any processors from reading the old mapping (with the old
attribute) from the VHPT after this point.
2. ptc.ga [X] ;; // Global shootdown and ALAT invalidate
// for the entire page
This removes the mapping from all processor TC's in the coherence domain, and
it forces all processors to flush any pending WC or UC stores from write buffers.
Table 4-17.
ALAT Behavior on Non-faulting Advanced/Check Loads
Memory
Attribute
ld.sa
Response
ld.a
Response
ld.c.clr,
ld.c.clr.acq,
ldf.c.clr
Response
ld.c.nc,
ldf.c.nc
Response
No NaT
NaT
ALAT
Hit
ALAT
Miss
ALAT
Hit
ALAT
Miss
speculative
alloc
remove
alloc
remove
nop
unchanged
a
a. May allocate a new ALAT entry if size and/or address are different than the corresponding ld.a or ld.sa whose
ALAT entry was matched.
alloc
non-speculative
N/A
remove
remove
undefined
nop
undefined
must not
alloc
limited speculation
N/A
remove
alloc
remove
nop
alloc
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 ...