| 0,0 → 1,759 |
|---|
| <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" |
| "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd"> |
| <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en"> |
| <head> |
| <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> |
| <meta name="generator" content="AsciiDoc 8.5.3" /> |
| <link rel="stylesheet" href="./xhtml11.css" type="text/css" /> |
| <link rel="stylesheet" href="./xhtml11-quirks.css" type="text/css" /> |
| <link rel="stylesheet" href="./layout1.css" type="text/css" /> |
| <script type="text/javascript"> |
| /*<![CDATA[*/ |
| window.onload = function(){asciidoc.footnotes();} |
| /*]]>*/ |
| </script> |
| <script type="text/javascript" src="./asciidoc-xhtml11.js"></script> |
| <title>README</title> |
| </head> |
| <body> |
| <div id="layout-banner"> |
| <div id="layout-title">AVRA</div> |
| <div id="layout-description">Assember for the Atmel AVR microcontroller family</div> |
| </div> |
| <table> |
| <tr valign="top"> |
| <td id="layout-menu"> |
| <div>»<a href="index.html">Home</a></div> |
| <div>»<a href="README.html">Readme</a></div> |
| <div>»<a href="downloads.html">Downloads</a></div> |
| <div>»<a href="ChangeLog.html">ChangeLog</a></div> |
| <div>»<a href="http://sourceforge.net/projects/avra">Sourceforge</a></div> |
| <div id="page-source">»<a href="README.txt">Page Source</a></div> |
| </td> |
| <td> |
| <div id="layout-content"> |
| <div id="header"> |
| <h1>README</h1> |
| </div> |
| <div id="content"> |
| <h2 id="_general_and_licensing_information">General and licensing information</h2> |
| <div class="sectionbody"> |
| <div class="paragraph"><p>AVRA v1.3.0 - Assember for the Atmel AVR microcontroller family</p></div> |
| <h3 id="_licensing_information">Licensing information</h3><div style="clear:left"></div> |
| <div class="paragraph"><p>This program is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2 of the License, or |
| (at your option) any later version. Please read below for for information.</p></div> |
| <h3 id="_disclaimer">Disclaimer</h3><div style="clear:left"></div> |
| <div class="paragraph"><p>This program is distributed in the hope that it will be useful, but |
| WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU General Public License for more details.</p></div> |
| <h3 id="_gnu_general_public_license">GNU General Public License</h3><div style="clear:left"></div> |
| <div class="paragraph"><p>You should have received a copy of the GNU General Public License |
| along with this program; see the file "COPYING". If not, visit |
| <a href="http://www.gnu.org">http://www.gnu.org</a> or write to the Free Software Foundation, Inc., |
| 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. You can |
| also contact the authors of AVRA to receive a copy of the COPYING file.</p></div> |
| <h3 id="_trademarks_and_copyright">Trademarks and copyright</h3><div style="clear:left"></div> |
| <div class="paragraph"><p>Atmel, AVR, AVR Studio, Intel, Windows are registered enterprises, brands |
| and registered trademarks. The mentioned companies have no relation to |
| AVRA and are therefore not responslible for any problems that occur when |
| using AVRA. Many thanks for your products, support and efforts.</p></div> |
| </div> |
| <h2 id="_introducion">Introducion</h2> |
| <div class="sectionbody"> |
| <div class="paragraph"><p>AVRA is an assembler for Atmel AVR microcontrollers, and it is almost |
| compatible with Atmel’s own assembler AVRASM32. The programming |
| principles and conceptions are based on the ANSI programming language "C".</p></div> |
| <div class="paragraph"><p>The initial version of AVRA was written by John Anders Haugum. He released |
| all versions until v0.7. All later versions were released by Tobias Weber.</p></div> |
| <h3 id="_differences_between_avra_and_avrasm32">Differences between AVRA and AVRASM32</h3><div style="clear:left"></div> |
| <div class="paragraph"><p>There are some differences between the original Atmel assembler AVRASM32 and AVRA. Basically AVRA is designed to replace AVRASM32 without special changes in your current Atmel AVR Studio enviroment. |
| Command line options have been adapted as far as it was possible until now. Jumping to fault containing line directly by double-clicking on the error message in the output window does work as with AVRASM32.</p></div> |
| <h3 id="_the_differences_in_detail">The differences in detail</h3><div style="clear:left"></div> |
| <div class="ulist"><ul> |
| <li> |
| <p> |
| Support for some extra preprocessor directives. |
| </p> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>.define, .undef, .ifdef, .ifndef, .if, .else, .endif, .elif, .elseif, .warning</tt></pre> |
| </div></div> |
| </li> |
| <li> |
| <p> |
| Not all command line options are supported. |
| Specifying an eeprom file (-e) is not supported. All eeprom data is |
| put out into a file called program.eep.hex and always Intel hex |
| format. Other hex file formats than Intel are currently not supported. |
| </p> |
| </li> |
| <li> |
| <p> |
| Forward references not supported for .ifdef and .ifndef directives. |
| This makes sure, that directives like .ifdef and .undef are working |
| properly. If you are familiar with the C programming language, you |
| should get easily into AVRA. See chapter "Programming techniques" for |
| more information about how to write proper code. |
| </p> |
| </li> |
| <li> |
| <p> |
| Enhanced macro support |
| AVRA has some new features for writing flexible macros. This should |
| increase the ability to reuse code e.g. build your own library. |
| </p> |
| </li> |
| <li> |
| <p> |
| Debugging support |
| AVRA creates a coff file everytime the assembly was sucessful. This |
| file allows AVR Studio or any coff compatible debugger to simulate |
| or emulate the program. |
| </p> |
| </li> |
| <li> |
| <p> |
| Meta tags for assembly time |
| This helps you tracking versions of your software and can also be |
| used to generate customer specific serial numbers. |
| </p> |
| </li> |
| </ul></div> |
| <h3 id="_compatibility">Compatibility</h3><div style="clear:left"></div> |
| <div class="paragraph"><p>Since AVRA is written in ANSI C, it should be possible to compile it on |
| most system platforms. If you have problems compiling AVRA, please leave |
| a message on the sourceforge message board or send a mail to the |
| authors of AVRA.</p></div> |
| </div> |
| <h2 id="_installation">Installation</h2> |
| <div class="sectionbody"> |
| <div class="paragraph"><p>To install avra you should copy the avra-executable to an apropriate |
| location. To compile you should rename the appropriate makefile, and |
| perform a make (use smake for Amiga SAS/C, and nmake for Mickeysoft |
| visual c++).</p></div> |
| <h3 id="_linux">Linux</h3><div style="clear:left"></div> |
| <div class="paragraph"><p>To compile avra you need gcc and the automake utilities. These will create |
| a ./configure script that evaluates your system enviroment. To get the |
| AVRA executable, you have to issue the following commands:</p></div> |
| <div class="paragraph"><p>aclocal |
| autoconf |
| automake -a |
| ./configure |
| make && make install</p></div> |
| <h3 id="_amigaos">AmigaOS</h3><div style="clear:left"></div> |
| <div class="paragraph"><p>avra can be copied any apropriate directory. If you are using the source |
| distribution a <em>make install</em> will do the same.</p></div> |
| <h3 id="_microsoft_windows">Microsoft Windows</h3><div style="clear:left"></div> |
| <div class="paragraph"><p>If you received the Windows binary package, look into the \bin |
| directory where you can find avra.exe. This should be copied to any |
| apropriate location. You can also overwrite AVRASM32.EXE in your |
| Atmel AVR Studio. If you want to compile it yourself you could download then |
| OpenWatcom C/C++ Toolchain for windows and create a new project and add the C |
| and H files to it and compile.</p></div> |
| <h3 id="_apple_os_x">Apple OS X</h3><div style="clear:left"></div> |
| <div class="paragraph"><p>If you recieved the Apple OS X binary package, look into the bin directory this |
| file is compiled universal and should run on intel 32 and 64 bit and powerpc. If |
| you want to compile it yourself go to the src directory and invoke <tt>make -f |
| makefiles/Makefiles.osx</tt> and then the executable should be created.</p></div> |
| </div> |
| <h2 id="_synopsis">Synopsis</h2> |
| <div class="sectionbody"> |
| <h3 id="_command_line_usage">Command line usage</h3><div style="clear:left"></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>usage: AVRA [-f][O|M|I|G] output file type |
| [-o <filename>] output file name |
| [-l <filename>] generate list file |
| [-m <mapfile>] generate map file |
| [--define <symbol>[=<value>]] [--includedir <dir>] [--listmac] |
| [--max_errors <number>] [--devices] [--version] |
| [-h] [--help] general help |
| [-W NoRegDef] supress register redefinition warnings |
| <file to assemble></tt></pre> |
| </div></div> |
| <h3 id="_parameter_list">Parameter list</h3><div style="clear:left"></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>--listfile -l : Create list file |
| --mapfile -m : Create map file |
| --define -D : Define symbol. |
| --includedir -I : Additional include dirs. |
| --listmac : List macro expansion in listfile. |
| --max_errors : Maximum number of errors before exit |
| (default: 10) |
| --devices : List out supported devices. |
| --version : Version information. |
| --help, -h : This help text.</tt></pre> |
| </div></div> |
| <h3 id="_warning_supression">Warning supression</h3><div style="clear:left"></div> |
| <div class="paragraph"><p>Since avra 1.1 there is a possibility to supress certain warnings. |
| Currently only register reassignment warnings can be supressed.</p></div> |
| <div class="paragraph"><p>Example: avra -W NoRegDef</p></div> |
| </div> |
| <h2 id="_programming_techniques">Programming techniques</h2> |
| <div class="sectionbody"> |
| <h3 id="_using_directives">Using directives</h3><div style="clear:left"></div> |
| <div class="paragraph"><p>AVRA offers a number of directives that are not part of Atmel’s |
| assembler. These directives should help you creating versatile code that |
| can be designed more modular.</p></div> |
| <h4 id="_directive_define">Directive .define</h4> |
| <div class="paragraph"><p>To define a constant, use ".define". This does the same thing as ".equ", |
| it is just a little more C style. Keep in mind that AVRA is not case |
| sensitive. Do not mix ".def" and ".define", because ".def" is used to |
| assign registers only. This is due to backward compatibility to Atmel’s |
| AVRASM32. Here is an example on how .define can be used.</p></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>.define network 1</tt></pre> |
| </div></div> |
| <div class="paragraph"><p>Now "network" is set to the value 1. You may want to assemble a specific |
| part of your code depeding on a define or switch setting. You can test |
| your defined word on existence (.ifdef and .ifndef) as well as on the |
| value it represents. The following code shows a way to prevent error |
| messages due to testing undefined constants. Conditional directives must |
| always end with an .endif directive.</p></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>.ifndef network |
| .define network 0 |
| .endif</tt></pre> |
| </div></div> |
| <h4 id="_directive_if_and_else">Directive .if and .else</h4> |
| <div class="paragraph"><p>The three lines in the last example set the default value of "network". |
| In the next example, you see how we can use default values. If a constant |
| has not defined previously, it is set to zero. Now you can test wether |
| e.g. network support is included into the assemby process.</p></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>.if network = 1 |
| .include "include\tcpip.asm" |
| .else |
| .include "include\dummynet.asm" |
| .endif</tt></pre> |
| </div></div> |
| <div class="paragraph"><p>In the second part of the above listing you see the use of .else, which |
| defines the part of the condition that is being executed if the equation |
| of the preceding .if statement is not equal. You can also use the else |
| statement to test another equasion. For that purpose use .elif, which |
| means "else if". Always close this conditional part with ".endif"</p></div> |
| <h4 id="_directive_error">Directive .error</h4> |
| <div class="paragraph"><p>This directive can be used to throw errors if a part in the code has reached |
| that should not be reached. The following example shows how we can stop |
| the assembly process if a particular value has not been previously set.</p></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>.ifndef network |
| .error "network is not configured!" ;the assembler stops here</tt></pre> |
| </div></div> |
| <h4 id="_directive_nolist_and_list">Directive .nolist and .list</h4> |
| <div class="paragraph"><p>The ouput to the list file can be paused by this two directives. After |
| avra discovers a .nolist while assembling, it stops output to the list file. |
| After a .list directive is detected, it continues the normal list file output.</p></div> |
| <h4 id="_directive_includepath">Directive .includepath</h4> |
| <div class="paragraph"><p>By default, any file that is included from within the source file must |
| either be a single filename or a complete absolute path. With the directive |
| .includepath you can set an additional include path . Furthermore you can |
| set as many include paths as you want. Be sure not no use same filename |
| in separate includes, because then it is no longer clear which one avra |
| should take.</p></div> |
| </div> |
| <h2 id="_using_include_files">Using include files</h2> |
| <div class="sectionbody"> |
| <div class="paragraph"><p>To avoid multiple inclusions of include files, you may use some pre- |
| processor directives. See example file stack.asm that is being included |
| into the main programm file as well as in other include files.</p></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>.ifndef _STACK_ASM_ |
| .define _STACK_ASM_</tt></pre> |
| </div></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>.include "include/config.inc"</tt></pre> |
| </div></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>; *** stack macro ***</tt></pre> |
| </div></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>.dseg |
| m_stack: .byte __stack_size__ |
| .cseg</tt></pre> |
| </div></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>.macro stack_setup |
| load [v:w,m_stack + __stack_size__] |
| outp [SPREG,v:w] |
| .endm</tt></pre> |
| </div></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>.endif ; avoid multiple inclusion of stack.asm</tt></pre> |
| </div></div> |
| <h3 id="_using_build_date_meta_tags">Using build date meta tags</h3><div style="clear:left"></div> |
| <div class="paragraph"><p>If you like to implement compiler build time and date into your |
| program, you can make use of some sepcial tags that avra supports.</p></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>%MINUTE% is being replaced by the current minute (00-59) |
| %HOUR% is being replaced by the current hour (00-23) |
| %DAY% is being replaced by the current day of month (01-31) |
| %MONTH% is being replaced by the current month (01-12) |
| %YEAR% is being replaced by the current year (2004-9999)</tt></pre> |
| </div></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>buildtime: .db "Release date %DAY%.%MONTH%.%YEAR% %HOUR%:%MINUTE%"</tt></pre> |
| </div></div> |
| <div class="paragraph"><p>This line will then assembled by avra into:</p></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>buildtime: .db "Release date 10.05.2004 19:54"</tt></pre> |
| </div></div> |
| <div class="paragraph"><p>You may also create a self defined serial number with meta tags:</p></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>.define serialnumber %DAY% + %MONTH%*31 + (%YEAR% - 2000) *31*12</tt></pre> |
| </div></div> |
| <div class="paragraph"><p>The %TAG% is translated before any other parsing happens. The real |
| output can be found in the list file.</p></div> |
| </div> |
| <h2 id="_macro_features">Macro features</h2> |
| <div class="sectionbody"> |
| <div class="paragraph"><p>Sometimes you have to work with 16 bit or greater variables stored |
| in 8 bit registers. The enhanced macro support allows you to write short |
| and flexible macros that simplify access to big variables. The extended |
| mode is active, as soon as you use parenthesis like this "[ ]" to wrap |
| macro parameters.</p></div> |
| <h3 id="_auto_type_conversion_for_macros">Auto type conversion for macros</h3><div style="clear:left"></div> |
| <div class="paragraph"><p>Values representing more than 8 Bits are usualy kept in a set of byte |
| wide registers. To simplify 16 Bit or greater operations, I added a new |
| language definitions. Words can be written as r16:r17, whereas register |
| r16 contains the higher part and register r17 the lower part of this |
| 16 Bit value.</p></div> |
| <h4 id="_macro_data_types">Macro data types</h4> |
| <div class="paragraph"><p>There are 3 data types that can be used. They will be added as character |
| separated by one underline character.</p></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>immediate values _i |
| registers _8,_16,_24,_32,_40,_48,_56,_64 |
| void parameter _v</tt></pre> |
| </div></div> |
| <div class="paragraph"><p>16 Bit Source and Destionation registers <em>dst</em> and <em>src</em></p></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>src = YH:YL |
| dst = ZH:ZL</tt></pre> |
| </div></div> |
| <div class="paragraph"><p>Within the parenthesis, the two words src and dst are interpreted as YH:YL |
| and ZH:ZL. Normal code outside of the macro parameter parenthesis can |
| still make use of these special key words "src" and "dst".</p></div> |
| <h4 id="_examples_for_automatic_type_conversion">Examples for automatic type conversion</h4> |
| <div class="paragraph"><p>To simplify the parameters in the demonstration below, we need to |
| redefine some registers.</p></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>.def a = r16 ; general purpose registers |
| .def b = r17 |
| .def c = r18 |
| .def d = r19</tt></pre> |
| </div></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>.def w = r20 ; working register |
| .def v = r21 ; working register</tt></pre> |
| </div></div> |
| <div class="paragraph"><p>If we substract 16 Bit values stored in a, higher byte and b, lower byte |
| with that in c:d, we usually have to use the following command sequence:</p></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>sub b,d |
| sbc a,c</tt></pre> |
| </div></div> |
| <div class="paragraph"><p>Now we can do the following steps to simplify 16 or more Bit manipulations</p></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>.macro subs |
| .message "no parameters specified" |
| .endm</tt></pre> |
| </div></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>.macro subs_16_16 |
| sub @1,@3 |
| sbc @0,@2 |
| .endm</tt></pre> |
| </div></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>.macro subs_16_8 |
| sub @1,@2 |
| sbci @0,0 |
| .endm</tt></pre> |
| </div></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>;now we can write a 16 Bit subraction as:</tt></pre> |
| </div></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>subs [a:b,c:d]</tt></pre> |
| </div></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>;or for calculating 16 minus 8 Bit</tt></pre> |
| </div></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>subs [a:b,c]</tt></pre> |
| </div></div> |
| <h3 id="_overloading_macros">Overloading macros</h3><div style="clear:left"></div> |
| <div class="paragraph"><p>Like in you are used to C functions, you can write macros for different |
| parameter lists. If you would like to have a versatile macro, you can |
| specify a unique macro for each parameter situation. See the next sample.</p></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>.macro load</tt></pre> |
| </div></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>; this message is shown if you use the macro within your code |
| ; specifying no parameters. If your macro allows the case where |
| ; no parameters are given, exchange .message with your code.</tt></pre> |
| </div></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>.message "no parameters specified" |
| .endm</tt></pre> |
| </div></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>; Here we define the macro "load" for the case it is being used |
| ; with two registers as first parameter and a immediate (constant) |
| ; value as second parameter.</tt></pre> |
| </div></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>.macro load_16_i |
| ldi @0,high(@2) |
| ldi @1,low(@2) |
| .endm</tt></pre> |
| </div></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>; the same case, but now with a 32 bit register value as first |
| ; parameter</tt></pre> |
| </div></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>.macro load_32_i |
| ldi @0,BYTE4(@4) |
| ldi @1,BYTE3(@4) |
| ldi @2,high(@4) |
| ldi @3,low(@4) |
| .endm</tt></pre> |
| </div></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>; Now let's see how these macros are being used in the code</tt></pre> |
| </div></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>load [a:b,15] ;uses macro load_16_i to load immediate</tt></pre> |
| </div></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>load [a:b:c:d,15] ;uses macro load_32_i to load immediate</tt></pre> |
| </div></div> |
| <h3 id="_more_examples">More examples</h3><div style="clear:left"></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>.dseg |
| counter .byte 2 |
| .cseg</tt></pre> |
| </div></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>.macro poke |
| .message "no parameters" |
| .endm</tt></pre> |
| </div></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>.macro poke_i_16_i |
| ldi @1,high(@3) |
| sts @0+0,@1 |
| ldi @2,low(@3) |
| sts @0+1,@2 |
| .endm</tt></pre> |
| </div></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>.macro poke_i_i |
| ldi w,@1 |
| sts @0+0,w |
| .endm</tt></pre> |
| </div></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>.macro poke_i_v_i |
| ldi w,high(@3) |
| sts @0+0,w |
| ldi w,low(@3) |
| sts @0+1,w |
| .endm</tt></pre> |
| </div></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>.macro poke_i_v_v_v_i |
| ldi w,high(@3) |
| sts @0+0,w |
| ldi w,low(@3) |
| sts @0+1,w |
| ldi w,BYTE3(@3) |
| sts @0+2,w |
| ldi w,BYTE4(@3) |
| sts @0+3,w |
| .endm</tt></pre> |
| </div></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>; this writes '9999' into the memory at 'counter' |
| ; uses only the working register for transfering the values.</tt></pre> |
| </div></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>poke [counter,w:w,9999]</tt></pre> |
| </div></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>; works same as above, but the transferred value '9999' is also |
| ; kept in the pair of register a:b</tt></pre> |
| </div></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>poke [counter,a:b,9999]</tt></pre> |
| </div></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>; in my design 'w' is always working reg. which implies that |
| ; it cannot be used for normal variables. The following example |
| ; uses poke_i_i because the parameter contains two immediate values.</tt></pre> |
| </div></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>poke [counter,9999] ;uses poke_i_i</tt></pre> |
| </div></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>; to be able to choose between a 8,16 or 32 Bit operation, you just |
| ; add a void parameter.</tt></pre> |
| </div></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>poke [counter,,9999] ;uses poke_i_v_i</tt></pre> |
| </div></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>; and the same for 32 Bit pokes</tt></pre> |
| </div></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>poke [counter,,,,9999] ;uses poke_i_v_v_v_i</tt></pre> |
| </div></div> |
| <h3 id="_loops_within_macros">Loops within macros</h3><div style="clear:left"></div> |
| <div class="paragraph"><p>One problem you may have experienced, is that labels defined within macros |
| are defined twice if you call the macro for example two times. Now you can |
| use labels for macro loops. Loops within macros must end with <em>_%</em>. the |
| "%" symbol is replaced by a running number.</p></div> |
| <h4 id="_loop_example">Loop example</h4> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>; Definition of the macro</tt></pre> |
| </div></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>.macro write_8_8 |
| write_%: |
| st Z+,@0 |
| dec @1 |
| brne write_% |
| .endm</tt></pre> |
| </div></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>; Use in user code</tt></pre> |
| </div></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>write [a,b] |
| write [c,d]</tt></pre> |
| </div></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>; After assembling this code, the result looks like this</tt></pre> |
| </div></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>write_1: |
| st Z+,a |
| dec b |
| brne write_1 |
| write_2: |
| st Z+,c |
| dec d |
| brne write_2</tt></pre> |
| </div></div> |
| </div> |
| <h2 id="_warnings_and_errors">Warnings and Errors</h2> |
| <div class="sectionbody"> |
| <div class="paragraph"><p>Some errors and warnings may confuse you a little bit so we will try to |
| clear some frequently asked questions about such cases.</p></div> |
| <h3 id="_constant_out_of_range">Constant out of range</h3><div style="clear:left"></div> |
| <div class="paragraph"><p>This warning occurs if a value exceeds the byte or word value of a assignment. |
| Read the comment posted by Jim Galbraith:</p></div> |
| <div class="paragraph"><p>The expression (~0x80) is a Bitwise Not operation. This |
| operator returns the input expression with all its bits |
| inverted. If 0x80 represents -128, then 0x7f, or +127 |
| should be ok. If this is considered as a 32-bit expression |
| (AVRA internal representation), then it appears to be more |
| like oxffffffff-0x80 or 0xffffffff<sup>0x80. The result would then |
| be 0xffffff7f. The assembler would then have to be told or it |
| would have to decide, based on context, how much |
| significance to assign to the higher bits. I have also |
| encountered such conditions with various assemblers, |
| including AVRA. To make sure the assembler does what I |
| really want, I use a construct like 0xff-0x80 or 0xff</sup>0x80. |
| This way the bit significance cannot extend beyond bit-7 and |
| there cannot be any misunderstanding.</p></div> |
| <h3 id="_can_8217_t_use_db_directive_in_data_segment">Can’t use .DB directive in data segment</h3><div style="clear:left"></div> |
| <div class="paragraph"><div class="title">DB and .DW is only used to assign constant data in eeprom or code space.</div><p>The reason why using it within data segment is forbidden is, that you |
| cannot set ram content at assembly time. The values must be programmed into |
| ROM area and at boot read from ROM into RAM. This is up to the user code. |
| You can only allocate memory for your variables using labels and the .byte |
| directive.</p></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>.dseg |
| my_string: .byte 15</tt></pre> |
| </div></div> |
| <h3 id="_byte_directive">BYTE directive</h3><div style="clear:left"></div> |
| <div class="paragraph"><div class="title">BYTE directive can only be used in data segment (.DSEG)</div><p>This directive cannot be used in code or eeprom region because this only |
| allocates memory without assgning distinct values to it. Please use .db |
| or .dw instead.</p></div> |
| <h3 id="_internal_assembler_error">Internal assembler error</h3><div style="clear:left"></div> |
| <div class="paragraph"><p>If you get an "Internal assembler error" please contact the project maintainer |
| by sending him a code example and a description of your working enviroment.</p></div> |
| </div> |
| <h2 id="_avra_internals">AVRA internals</h2> |
| <div class="sectionbody"> |
| <div class="paragraph"><p>This section provides thoughts of the avra internal design. I have to admit |
| that the code of avra is anything else than clean and optimized. To increase |
| the code readability I will try to give you some standards that should improve |
| quality. The following standards are similar to what GNU proposes.</p></div> |
| <h3 id="_coding_standards">Coding standards</h3><div style="clear:left"></div> |
| <div class="paragraph"><p>Tab space is always 2 spaces. The Tab character (ascii 9) is not used. |
| if,while,for are always opened on the same line but closed on the next line. |
| The closing bracket is in the same column as the first letter of the loop |
| directive.</p></div> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>Example:</tt></pre> |
| </div></div> |
| <div class="listingblock"> |
| <div class="content"> |
| <pre><tt> while(i > 0) { |
| do_something(); |
| }</tt></pre> |
| </div></div> |
| </div> |
| <h2 id="_credits">Credits</h2> |
| <div class="sectionbody"> |
| <div class="paragraph"><p>We would like to thank the following people for giving contributions, |
| patches and bug reports, as well as suggestions and new ideas.</p></div> |
| <div class="listingblock"> |
| <div class="content"> |
| <pre><tt> Jon Anders Haugum (project founder) |
| Burkhard Arenfeld (release 1.2.0) |
| Tobias Weber (old maintainer) |
| Jerry Jacobs (release 1.3.0) |
| Bernt Hembre |
| Nils Strøm |
| Roberto Biancardi |
| Qwerty Jones |
| Ben Hitchcock (Maker of the mac port) |
| Daniel Drotos |
| Laurence Boyd II |
| Varuzhan Danielyan |
| Laurence Turner |
| Eugene R. O'Bryan |
| Dmitry Dicky |
| Bob Harris (Maker of coff support) |
| Tobias Weber (enhanced macro support) |
| Lesha Bogdanow |
| Jim Galbraith |
| Mark Brinicombe |
| Igor Nikolayenko |
| Peter Hettkamp |
| Herb Poppe |
| David Burke |
| Alexey Pavluchenko |
| Alan Probandt |
| Mariusz Matuszek |
| Arne Rossius |
| Marti Tichacek |
| Patrick Parity |
| Johannes Overmann |
| Roland Riegel |
| Peter Katzmann |
| Donald D. Davis</tt></pre> |
| </div></div> |
| <div class="paragraph"><p>And all the anonymous people who submitted patches!</p></div> |
| <div class="paragraph"><p>Thank you for your work and support.</p></div> |
| </div> |
| <h2 id="_references">References</h2> |
| <div class="sectionbody"> |
| <div class="literalblock"> |
| <div class="content"> |
| <pre><tt>http://www.suprafluid.com/avra |
| http://www.avrfreaks.de |
| http://www.atmel.com</tt></pre> |
| </div></div> |
| </div> |
| </div> |
| <div id="footnotes"><hr /></div> |
| <div id="footer"> |
| <div id="footer-text"> |
| Version 1.3.0<br /> |
| Last updated 2010-06-28 16:04:26 CEST |
| </div> |
| <div id="footer-badges"> |
| <a href="http://validator.w3.org/check?uri=referer"> |
| <img style="border:0;width:88px;height:31px" |
| src="http://www.w3.org/Icons/valid-xhtml11-blue" |
| alt="Valid XHTML 1.1" height="31" width="88" /> |
| </a> |
| <a href="http://jigsaw.w3.org/css-validator/"> |
| <img style="border:0;width:88px;height:31px" |
| src="http://jigsaw.w3.org/css-validator/images/vcss-blue" |
| alt="Valid CSS!" /> |
| </a> |
| <a href="http://www.mozilla.org/products/firefox/"> |
| <img style="border:none; width:110px; height:32px;" |
| src="http://www.spreadfirefox.com/community/images/affiliates/Buttons/110x32/safer.gif" |
| alt="Get Firefox!" /> |
| </a> |
| </div> |
| </div> |
| </div> |
| </td> |
| </tr> |
| </table> |
| </body> |
| </html> |