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F.APPENDIX
219
S
Summary of Differences between
SPARC64 V and UltraSPARC-III
The following table summarizes differences between SPARC64 V and UltraSPARC-III
ISAs. This list is a summary, not an exhaustive list.
TABLE T-1
SPARC64 V and UltraSPARC-III Differences
(1 of 3)
Feature SPARC64 V
SPARC64 V
Page UltraSPARC-III
UltraSPARC-
III Section
MMU
architecture
SPARC64 V supports an
UltraSPARC II-based MMU model.
TLBs are split between instruction
and data. Each side has a 2-level
TLB hierarchy.
85 UltraSPARC-III implements a flat
extended version of UltraSPARC
II’s MMU architecture.
F-1
TTE format SPARC64 V supports a 43-bit
physical address. In addition, the
CV bit is ignored and unaliasing is
maintained by hardware.
86 UltraSPARC-III supports a 43-bit
physical address. Millennium
will support a 47-bit PA.
F-2
TLB locking
mechanism
Lock entries are supported in both
fully-associative ITLB (fITLB) and
fully-associative DTLB (fDTLB), 32-
entry each.
86 Lock entries supported only in
the 16-entry fully-associative
TLBs.
F-1, F-2
TSB hashing
algorithm
Direct hashing with contents of the
Context-ID register (13-bit). Has a
UltraSPARC I/II compatibility
mode.
88 Hash field in pointer extension is
used for hashing address. Setting
0 in the field maintains
compatibility with UltraSPARC
I/II.
F. 10.7
Floating-point
Multiply-ADD
SPARC64 V implements these
instructions in IMPDEP2.
50 Does not support FMA
instructions.
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