User Guide

Preface xxiii
24592—Rev. 3.15—November 2009 AMD64 Technology
offset
Same as displacement.
overflow
The condition in which a floating-point number is larger in magnitude than the largest, finite,
positive or negative number that can be represented in the data-type format being used.
packed
See vector.
PAE
Physical-address extensions.
physical memory
Actual memory, consisting of main memory and cache.
probe
A check for an address in a processor’s caches or internal buffers. External probes originate
outside the processor, and internal probes originate within the processor.
protected mode
A submode of legacy mode.
quadword
Four words, or eight bytes, or 64 bits.
RAZ
Read as zero (0), regardless of what is written.
real-address mode
See real mode.
real mode
A short name for real-address mode, a submode of legacy mode.
relative
Referencing with a displacement (also called offset) from an instruction pointer rather than the
base of a code segment. Contrast with absolute.
reserved
Fields marked as reserved may be used at some future time.
To preserve compatibility with future processors, reserved fields require special handling when
read or written by software.
Reserved fields may be further qualified as MBZ, RAZ, SBZ or IGN (see definitions).