Motorola MPC750 User Manual page 437

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Boundedly undefined. A characteristic of certain operation results that are
not rigidly prescribed by the PowerPC architecture. Boundedly-
undefined results for a given operation may vary among
implementations and between execution attempts in the same
implementation.
Although the architecture does not prescribe the exact behavior for
when results are allowed to be boundedly undefined, the results of
executing instructions in contexts where results are allowed to be
boundedly undefined are constrained to ones that could have been
achieved by executing an arbitrary sequence of defined instructions,
in valid form, starting in the state the machine was in before
attempting to execute the given instruction.
Branch folding. The replacement with target instructions of a branch
instruction and any instructions along the not-taken path when a
branch is either taken or predicted as taken.
Branch prediction-The process of guessing whether a branch will be
taken. Such predictions can be correct or incorrect; the term
'predicted' as it is used here does not imply that the prediction is
correct (successful). The PowerPC architecture defines a means for
static branch prediction as part of the instruction encoding.
Branch resolution-The determination of whether a branch is taken or not
taken. A branch is said to be resolved when the processor can
determine which instruction path to take. If the branch is resolved as
predicted, the instructions following the predicted branch that may
have been speculatively executed can complete (see completion). If
the branch is not resolved as predicted, instructions on the
mispredicted path, and any results of speculative execution, are
purged from the pipeline and fetching continues from the
nonpredicted path.
Burst. A multiple-beat data transfer whose total size is typically equal to a
cache block.
C
Cache. High-speed memory contammg recently accessed data and/or
instructions (subset of main memory) .
Glossary-2 MPC750 RISC Microprocessor User's Manual