Revision: 6303
Author: [email protected]
Date: Thu Jan 13 23:28:04 2011
Log: Edited wiki page CrossCompilingForARM through web user interface.
http://code.google.com/p/v8/source/detail?r=6303
Modified:
/wiki/CrossCompilingForARM.wiki
=======================================
--- /wiki/CrossCompilingForARM.wiki Thu Jan 13 01:24:32 2011
+++ /wiki/CrossCompilingForARM.wiki Thu Jan 13 23:28:04 2011
@@ -4,7 +4,7 @@
The Sourcery G++ Lite cross compiler suite is a free version of Sourcery
G++ from [http://www.codesourcery.com CodeSourcery]. There is a page for
the [http://www.codesourcery.com/sgpp/lite/arm GNU Toolchain for ARM
Processors]. Determine the version you need for your host/target
combination.
-The following instructions uses
[http://www.codesourcery.com/sgpp/lite/arm/portal/release858 2009q1-203 for
ARM GNU/Linux], and if using a different version please change the URLs and
`TOOL_PREFIX`below accordingly.
+The following instructions uses
[http://www.codesourcery.com/sgpp/lite/arm/portal/release858 2009q1-203 for
ARM GNU/Linux], and if using a different version please change the URLs and
`TOOL_PREFIX` below accordingly.
== Installing on host and target ==
@@ -99,3 +99,17 @@
}}}
This script of course builds the whole of V8 two times, but that can be
avoided by using two build directories and the -Y option for scons.
+
+== Building for target which supports unaligned access ==
+
+The default when building V8 for an ARM target (either cross compiling or
compiling on an ARM machine) is to disable unaligned memory access. However
in some situations (most noticeably handling of regular expressions)
performance will be better if unaligned memory access is used on processors
which supports it. To enable unaligned memory access set
`unalignedaccesses` to `on` when building:
+
+{{{
+scons unalignedaccesses=on ...
+}}}
+
+When running in the simulator the default is to enable unaligned memory
access, so to test in the simulator with unaligned memory access disabled
set `unalignedaccesses` to `off` when building:
+
+{{{
+scons unalignedaccesses=off simulator=arm ...
+}}}
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