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added a page about LTR in the docs; other pages updated with links to this new LTR patch

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Bogdan Marinescu 2009-03-11 13:58:20 +00:00
parent 00ee06e90f
commit 27ffc016b7
3 changed files with 31 additions and 6 deletions
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18
doc/en/building.html
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@ -150,7 +150,17 @@ RAM) but will also completely remove the possibility of using that
module from <b>eLua</b>.</p>
<p>The modules included in the build are specified by the
LUA_PLATFORM_LIBS_ROM macro. An example is given below: </p>
<pre><code>#define LUA_PLATFORM_LIBS_ROM\<br> _ROM( AUXLIB_PIO, luaopen_pio, pio_map )\<br> _ROM( AUXLIB_TMR, luaopen_tmr, tmr_map )\<br> _ROM( AUXLIB_PD, luaopen_pd, pd_map )\<br> _ROM( AUXLIB_UART, luaopen_uart, uart_map )\<br> _ROM( AUXLIB_TERM, luaopen_term, term_map )\<br> _ROM( AUXLIB_PWM, luaopen_pwm, pwm_map )\<br> _ROM( AUXLIB_PACK, luaopen_pack, pack_map )\<br> _ROM( AUXLIB_BIT, luaopen_bit, bit_map )\<br> _ROM( AUXLIB_CPU, luaopen_cpu, cpu_map )\<br> _ROM( LUA_MATHLIBNAME, luaopen_math, math_map )</code></pre>
<pre><code>#define LUA_PLATFORM_LIBS_ROM\
_ROM( AUXLIB_PIO, luaopen_pio, pio_map )\
_ROM( AUXLIB_TMR, luaopen_tmr, tmr_map )\
_ROM( AUXLIB_PD, luaopen_pd, pd_map )\
_ROM( AUXLIB_UART, luaopen_uart, uart_map )\
_ROM( AUXLIB_TERM, luaopen_term, term_map )\
_ROM( AUXLIB_PWM, luaopen_pwm, pwm_map )\
_ROM( AUXLIB_PACK, luaopen_pack, pack_map )\
_ROM( AUXLIB_BIT, luaopen_bit, bit_map )\
_ROM( AUXLIB_CPU, luaopen_cpu, cpu_map )\
ROM( LUA_MATHLIBNAME, luaopen_math, math_map )</code></pre>
<p>Each module is defined by a <b>_ROM( module_name,
module_init_function, module_map_array )</b> macro, where:
</p>
@ -165,7 +175,7 @@ functions and constants exported by a module</li>
<p>Please note that this notation is specific to LTR (the <b>L</b>ua
<b>T</b>iny <b>R</b>AM patch) and it's not the
only way to specify the list of modules included in the build (although
it is the most common one). Check the <a href="">##LTR
it is the most common one). Check the <a href="arch_ltr.html#config">LTR
section</a> for more information about LTR.</p>
<p>For the full list of modules that can be enabled or disabled
via <i>platform_conf.h</i> check <a href="">##the
@ -304,7 +314,7 @@ very resource-constrained systems.
this specifies the name of the toolchain used to build the image. See <a href="toolchains.html#configuration">this link</a> for
details.</li>
<li><b>optram=0 | 1</b>: enables of disables the
LTR patch, see the <a href="">##LTR documentation</a>
LTR patch, see the <a href="arch_ltr.html">LTR documentation</a>
for more details. The default is 1, which enables the LTR patch.</li>
<li><b>prog</b>: by default, the above 'scons'
command will build only the 'elf' (executable) file. Specify "prog" to
@ -347,4 +357,4 @@ CodeSourcery toolchain instead of the default toolchain (which is a
"generic" ARM GCC toolchain, usually the one built by following
the tutorials from this site</p>
.
</body></html>
</body></html>

17
doc/en/faq.html
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@ -23,6 +23,8 @@ It is assumed that you already know what <b>eLua</b>, so here's a list of questi
<li><a href="faq.html#bytecode">I know that Lua can be compiled to bytecode, so I compiled one of the eLua examples with luac and tried to run it on
my eLua board, but it didn't work. Is this a bug in eLua?</li>
<li><a href="faq.html#outofmemory">I get "out of memory" errors when I run my Lua programs, what should I do?</li>
<li><a href="faq.html#rotables">I enabled the LTR patch, but now all my module tables (math, io, string, spi and so on) are read only. Do I have to
disable LTR if I want write access to these modules?</a>
</ul>
<hr>
@ -123,7 +125,7 @@ prove just fine. It largely depends on your needs.</p>
<p>There are a number of things you can try to overcome this:</p>
<ul>
<li><b>enable the LTR patch</b>: you can get very significant improvements if you enable the LTR patch in your <b>eLua</b> image. See
<a href="">##here</a> for more details about LTR, and <a href="building.html">here</a> for instructions about enabling LTR.</li>
<a href="arch_ltr.html">here</a> for more details about LTR, and <a href="building.html">here</a> for instructions about enabling LTR.</li>
<li><b>precompile your source to bytecode</b>: if you use bytecode instead of source code Lua won't need to compile your source, so you save some RAM.</li>
<li><b>try to avoid using too many strings</b>: strings are immutable in Lua. That means that a statement like <i>s = s .. "\n"</i> (where s is a string)
will create a new string each time it's called. If this happens a lot (for example in a loop), your memory will quickly run out because of all the
@ -132,4 +134,17 @@ prove just fine. It largely depends on your needs.</p>
<li><b>control Lua's garbage collection manually</b>: if you're still running out of memory, try calling <i>collectgarbage('collect')</i> from your code,
which will force a garbage collection and thus might free some memory.</li>
</ul>
<a name="rotables"><h2>I enabled the LTR patch, but now all my module tables (math, io, string, spi and so on) are read only. Do I have to
disable LTR if I want write access to these modules?</h2></a>
<p>You don't really have to disable LTR to get write access to your rotables, you can use some simple Lua "tricks" instead. Let's suppose that you need
write access to the <b>math</b> module. With LTR enabled, <b>math</b> is a rotable, so you can't change its keys/values. But you can use metatables
to overcome this limitation:</p>
<p><pre><code>local oldmath = math
math = { __index = oldmath }
setmetatable( math, math )
</code></pre></p>
<p>This way you can use <i>math</i> in "write mode" now (since it is a regular table), but you can still access the keys from the original <i>math</i>
rotable. Of course, if you need write access to <b>all</b> your modules (or to most of them) it makes more sense to disable LTR instead, but from our
observations this doesn't happen in practice.</p>
</body></html>

2
doc/en/status.html
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@ -495,7 +495,7 @@ difference between generic modules and platform specific modules, check
<td style="text-align: center;"><img src="../wb_img/stat_not_implemented.png"></td>
</tr>
<tr>
<td style="text-align: left;">eLua LTR (Lua Tiny RAM) patch &nbsp;##a link to a small description...</td>
<td style="text-align: left;"><a href="arch_ltr.html">eLua LTR (Lua Tiny RAM) patch</a></td>
<td style="text-align: center;"><img src="../wb_img/stat_ok.png"></td>
</tr>
<tr>