Mercurial > hg > index.cgi

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN""http://www.w3.org/TR/html4/loose.dtd">
<HTML
><HEAD
><TITLE
>Numbers and Expressions</TITLE
><META
NAME="GENERATOR"
CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK
REL="HOME"
TITLE="LW Tool Chain"
HREF="index.html"><LINK
REL="UP"
TITLE="LWASM"
HREF="c45.html"><LINK
REL="PREVIOUS"
TITLE="Symbols"
HREF="x180.html"><LINK
REL="NEXT"
TITLE="Assembler Directives"
HREF="x193.html"></HEAD
><BODY
CLASS="SECTION"
BGCOLOR="#FFFFFF"
TEXT="#000000"
LINK="#0000FF"
VLINK="#840084"
ALINK="#0000FF"
><DIV
CLASS="NAVHEADER"
><TABLE
SUMMARY="Header navigation table"
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TH
COLSPAN="3"
ALIGN="center"
>LW Tool Chain</TH
></TR
><TR
><TD
WIDTH="10%"
ALIGN="left"
VALIGN="bottom"
><A
HREF="x180.html"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="80%"
ALIGN="center"
VALIGN="bottom"
>Chapter 3. LWASM</TD
><TD
WIDTH="10%"
ALIGN="right"
VALIGN="bottom"
><A
HREF="x193.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
></TABLE
><HR
ALIGN="LEFT"
WIDTH="100%"></DIV
><DIV
CLASS="SECTION"
><H1
CLASS="SECTION"
><A
NAME="AEN185"
>3.5. Numbers and Expressions</A
></H1
><P
>&#13;Numbers can be expressed in binary, octal, decimal, or hexadecimal. Binary
numbers may be prefixed with a "%" symbol or suffixed with a "b" or "B".
Octal numbers may be prefixed with "@" or suffixed with "Q", "q", "O", or
"o". Hexadecimal numbers may be prefixed with "$", "0x" or "0X", or suffixed
with "H". No prefix or suffix is required for decimal numbers but they can
be prefixed with "&amp;" if desired. Any constant which begins with a letter
must be expressed with the correct prefix base identifier or be prefixed
with a 0. Thus hexadecimal FF would have to be written either 0FFH or $FF.
Numbers are not case sensitive.&#13;</P
><P
> A symbol may appear at any point where a number is acceptable. The
special symbol "*" can be used to represent the starting address of the
current source line within expressions. </P
><P
>The ASCII value of a character can be included by prefixing it with a
single quote ('). The ASCII values of two characters can be included by
prefixing the characters with a quote (").</P
><P
>&#13;LWASM supports the following basic binary operators: +, -, *, /, and %.
These represent addition, subtraction, multiplication, division, and
modulus.  It also supports unary negation and unary 1's complement (- and ^
respectively).  It is also possible to use ~ for the unary 1's complement
operator.  For completeness, a unary positive (+) is supported though it is
a no-op.  LWASM also supports using |, &#38;, and ^ for bitwise or, bitwise and,
and bitwise exclusive or respectively.&#13;</P
><P
>&#13;Operator precedence follows the usual rules. Multiplication, division, and
modulus take precedence over addition and subtraction.  Unary operators take
precedence over binary operators.  Bitwise operators are lower precdence
than addition and subtraction.  To force a specific order of evaluation,
parentheses can be used in the usual manner.&#13;</P
><P
>&#13;As of LWASM 2.5, the operators &#38;&#38; and || are recognized for boolean and and
boolean or respectively.  They will return either 0 or 1 (false or true).
They have the lowest precedence of all the binary operators.&#13;</P
></DIV
><DIV
CLASS="NAVFOOTER"
><HR
ALIGN="LEFT"
WIDTH="100%"><TABLE
SUMMARY="Footer navigation table"
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
><A
HREF="x180.html"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="index.html"
ACCESSKEY="H"
>Home</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
><A
HREF="x193.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
>Symbols</TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="c45.html"
ACCESSKEY="U"
>Up</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
>Assembler Directives</TD
></TR
></TABLE
></DIV
></BODY
></HTML
>
author	lost@l-w.ca
date	Wed, 07 Sep 2011 20:45:20 -0600
parents	83b7b4ce3bbd
children