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<!-- Copyright (C) 2003 Red Hat, Inc. --> <!-- This material may be distributed only subject to the terms --> <!-- and conditions set forth in the Open Publication License, v1.0 --> <!-- or later (the latest version is presently available at --> <!-- http://www.opencontent.org/openpub/). --> <!-- Distribution of the work or derivative of the work in any --> <!-- standard (paper) book form is prohibited unless prior --> <!-- permission is obtained from the copyright holder. --> <HTML ><HEAD ><TITLE >HAL Interfaces</TITLE ><meta name="MSSmartTagsPreventParsing" content="TRUE"> <META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+ "><LINK REL="HOME" TITLE="eCos Reference Manual" HREF="ecos-ref.html"><LINK REL="UP" TITLE="The eCos Hardware Abstraction Layer (HAL)" HREF="the-ecos-hardware-abstraction-layer.html"><LINK REL="PREVIOUS" TITLE="General principles" HREF="hal-general-principles.html"><LINK REL="NEXT" TITLE="Architecture Characterization" HREF="hal-architecture-characterization.html"></HEAD ><BODY CLASS="CHAPTER" 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" >eCos Reference Manual</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="hal-general-principles.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="hal-architecture-characterization.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><DIV CLASS="CHAPTER" ><H1 ><A NAME="HAL-INTERFACES">Chapter 9. HAL Interfaces</H1 ><DIV CLASS="TOC" ><DL ><DT ><B >Table of Contents</B ></DT ><DT ><A HREF="hal-interfaces.html#HAL-BASE-DEFINITIONS" >Base Definitions</A ></DT ><DT ><A HREF="hal-architecture-characterization.html" >Architecture Characterization</A ></DT ><DT ><A HREF="hal-interrupt-handling.html" >Interrupt Handling</A ></DT ><DT ><A HREF="hal-input-and-output.html" >HAL I/O</A ></DT ><DT ><A HREF="hal-cache-control.html" >Cache Control</A ></DT ><DT ><A HREF="hal-linker-scripts.html" >Linker Scripts</A ></DT ><DT ><A HREF="hal-diagnostic-support.html" >Diagnostic Support</A ></DT ><DT ><A HREF="hal-smp-support.html" >SMP Support</A ></DT ></DL ></DIV ><P >This section describes the main HAL interfaces. </P ><DIV CLASS="SECTION" ><H1 CLASS="SECTION" ><A NAME="HAL-BASE-DEFINITIONS">Base Definitions</H1 ><P >These are definitions that characterize the properties of the base architecture that are used to compile the portable parts of the kernel. They are concerned with such things a portable type definitions, endianness, and labeling.</P ><P >These definitions are supplied by the <TT CLASS="FILENAME" >cyg/hal/basetype.h</TT > header file which is supplied by the architecture HAL. It is included automatically by <TT CLASS="FILENAME" >cyg/infra/cyg_type.h</TT >.</P ><DIV CLASS="SECTION" ><H2 CLASS="SECTION" ><A NAME="AEN7743">Byte order</H2 ><P ></P ><DIV CLASS="VARIABLELIST" ><DL ><DT ><TT CLASS="VARNAME" >CYG_BYTEORDER</TT ></DT ><DD ><P > This defines the byte order of the target and must be set to either <TT CLASS="VARNAME" >CYG_LSBFIRST</TT > or <TT CLASS="VARNAME" >CYG_MSBFIRST</TT >. </P ></DD ></DL ></DIV ></DIV ><DIV CLASS="SECTION" ><H2 CLASS="SECTION" ><A NAME="AEN7753">Label Translation</H2 ><P ></P ><DIV CLASS="VARIABLELIST" ><DL ><DT ><TT CLASS="FUNCTION" >CYG_LABEL_NAME(name)</TT ></DT ><DD ><P > This is a wrapper used in some C and C++ files which use labels defined in assembly code or the linker script. It need only be defined if the default implementation in <TT CLASS="FILENAME" >cyg/infra/cyg_type.h</TT >, which passes the name argument unaltered, is inadequate. It should be paired with <TT CLASS="FUNCTION" >CYG_LABEL_DEFN()</TT >. </P ></DD ><DT ><TT CLASS="FUNCTION" >CYG_LABEL_DEFN(name)</TT ></DT ><DD ><P > This is a wrapper used in assembler sources and linker scripts which define labels. It need only be defined if the default implementation in <TT CLASS="FILENAME" >cyg/infra/cyg_type.h</TT >, which passes the name argument unaltered, is inadequate. The most usual alternative definition of this macro prepends an underscore to the label name. </P ></DD ></DL ></DIV ></DIV ><DIV CLASS="SECTION" ><H2 CLASS="SECTION" ><A NAME="AEN7769">Base types</H2 ><TABLE BORDER="5" BGCOLOR="#E0E0F0" WIDTH="70%" ><TR ><TD ><PRE CLASS="PROGRAMLISTING" > cyg_halint8 cyg_halint16 cyg_halint32 cyg_halint64 cyg_halcount8 cyg_halcount16 cyg_halcount32 cyg_halcount64 cyg_halbool</PRE ></TD ></TR ></TABLE ><P >These macros define the C base types that should be used to define variables of the given size. They only need to be defined if the default types specified in <TT CLASS="FILENAME" >cyg/infra/cyg_type.h</TT > cannot be used. Note that these are only the base types, they will be composed with <TT CLASS="LITERAL" >signed</TT > and <TT CLASS="LITERAL" >unsigned</TT > to form full type specifications.</P ></DIV ><DIV CLASS="SECTION" ><H2 CLASS="SECTION" ><A NAME="AEN7776">Atomic types</H2 ><TABLE BORDER="5" BGCOLOR="#E0E0F0" WIDTH="70%" ><TR ><TD ><PRE CLASS="PROGRAMLISTING" > cyg_halatomic CYG_ATOMIC</PRE ></TD ></TR ></TABLE ><P >These types are guaranteed to be read or written in a single uninterruptible operation. It is architecture defined what size this type is, but it will be at least a byte.</P ></DIV ></DIV ></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="hal-general-principles.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="ecos-ref.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="hal-architecture-characterization.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >General principles</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="the-ecos-hardware-abstraction-layer.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >Architecture Characterization</TD ></TR ></TABLE ></DIV ></BODY ></HTML >