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Notational conventions, Values, Ranges – Compaq W4000 User Manual

Page 21: Register notation and usage, Bit notation and byte values

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Technical Reference Guide

1.5 NOTATIONAL

CONVENTIONS


The notational guidelines used in this guide are described in the following subsections.

1.5.1 VALUES


Hexadecimal values are indicated by a numerical or alpha-numerical value followed by the letter
“h.” Binary values are indicated by a value of ones and zeros followed by the letter “b.”
Numerical values that have no succeeding letter can be assumed to be decimal unless otherwise
stated.

1.5.2 RANGES


Ranges or limits for a parameter are shown using the following methods:

Example A:

Bits <7..4> = bits 7, 6, 5, and 4.

Example B:

IRQ3-7, 9 = IRQ signals 3 through 7, and IRQ signal 9

1.5.3 REGISTER NOTATION AND USAGE


This guide uses standard Intel naming conventions in discussing the microprocessor’s (CPU)
internal registers. Registers that are accessed through programmable I/O using an indexing
scheme are indicated using the following format:

03C5.17h

Index port
Data port

In the example above, register 03C5.17h is accessed by writing the index port value 17h to the
index address (03C4h), followed by a write to or a read from port 03C5h.

1.5.4 BIT NOTATION AND BYTE VALUES


Bit designations are labeled between brackets (i.e., “bit <0 >”). Binary values are shown with the
most significant bit (MSb) on the far left, least significant bit (LSb) at the far right. Byte values in
hexadecimal are also shown with the MSB on the left, LSB on the right.

Compaq Evo and Workstation Personal Computers

Featuring the Intel Pentium 4 Processor

Second Edition – January 2003

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