FUJITSU Implementation Supplement Fujitsu SPARC64 V - Manual (Page 22)

Release 1.0, 1 July 2002 F. Chapter 2 Definitions 11
in parallel. When instructions are committed, results in renamed registers are
posted to the architected registers in the proper sequence to produce the correct
program results.
scan A method used to initialize all of the machine state within a chip. In a chip that
has been designed to be scannable, all of the machine state is connected in one
or several loops called “scan rings.” Initialization data can be scanned into the
chip through the scan rings. The state of the machine also can be scanned out
through the scan rings.
reservation station A holding location that buffers dispatched instructions until all input operands
are available. SPARC64 V implements dataflow execution based on operand
availability. When operands are available, the instructions in the reservation
station are scheduled for execution. Reservation stations also contain special
tag-matching logic that captures the appropriate operand data. Reservation
stations are sometimes referred to as queues (for example, the integer queue).
speculative A distribution system whereby a result is not guaranteed as known to be
correct or an operand state is not known to be valid. SPARC64 V employs
speculative distribution, meaning results can be distributed from functional
units before the point at which guaranteed validity of the result is known.
superscalar An implementation that allows several instructions to be issued, executed, and
committed in one clock cycle. SPARC64 V issues up to 4 instructions per clock
cycle.
sync Synonym: machine sync.
syncing instruction An instruction that causes a machine sync. Thus, before a syncing instruction is
issued, all previous instructions (in program order) must have been committed.
At that point, the syncing instruction is issued, executed, completed, and
committed by itself.
TLB Translation lookaside buffer.