Terminology And Conventions - Compaq 21264 Hardware Reference Manual

Terminology and Conventions

This section defines the abbreviations, terminology, and other conventions used
throughout this document.
Abbreviations
Binary Multiples
•
The abbreviations K, M, and G (kilo, mega, and giga) represent binary multiples
and have the following values.
K
M
G
For example:
2KB
4MB
8GB
2K pixels
4M pixels
• Register Access
The abbreviations used to indicate the type of access to register fields and bits have
the following definitions:
Abbreviation
IGN
MBZ
RAZ
RC
RES
RO
RO,n
Alpha 21264/EV67 Hardware Reference Manual
10
= 2 (1024)
20
= 2 (1,048,576)
30
= 2 (1,073,741,824)
= 2 kilobytes
= 4 megabytes = 4
= 8 gigabytes
= 2 kilopixels
= 4 megapixels = 4
Meaning
Ignore
Bits and fields specified are ignored on writes.
Must Be Zero
Software must never place a nonzero value in bits and fields specified as
MBZ. A nonzero read produces an Illegal Operand exception. Also, MBZ
fields are reserved for future use.
Read As Zero
Bits and fields return a zero when read.
Read Clears
Bits and fields are cleared when read. Unless otherwise specified, such bits
cannot be written.
Reserved
Bits and fields are reserved by Compaq and should not be used; however,
zeros can be written to reserved fields that cannot be masked.
Read Only
The value may be read by software. It is written by hardware. Software write
operations are ignored.
Read Only, and takes the value n at power-on reset.
The value may be read by software. It is written by hardware. Software write
operations are ignored.
10
= 2 2 bytes
20
2 bytes
30
= 8 2 bytes
10
= 2 2 pixels
20
2 pixels
xix