<code>arm</code> (a.k.a. <code>ARM</code>); <code>5g,5l,5c,5a</code>
</dt>
<dd>
- Supports only Linux binaries. Less widely used than the other ports and therefore not as thoroughly tested.
+ Supports Linux, FreeBSD and NetBSD binaries. Less widely used than the other ports.
</dd>
</dl>
</p>
<p>
-The compilers can target the FreeBSD, Linux, NetBSD, OpenBSD, OS X (Darwin),
+The compilers can target the FreeBSD, Linux, NetBSD, OpenBSD, OS X (Darwin), Plan 9,
and Windows operating systems.
The full set of supported combinations is listed in the discussion of
<a href="#environment">environment variables</a> below.
to override the defaults.
</p>
-<blockquote>
-
-<p><code>$GOROOT</code></p>
+<ul>
+<li><code>$GOROOT</code>
<p>
The root of the Go tree, often <code>$HOME/go</code>.
Its value is built into the tree when it is compiled, and
local copies of the repository.
</p>
-<p><code>$GOROOT_FINAL</code></p>
+<li><code>$GOROOT_FINAL</code>
<p>
The value assumed by installed binaries and scripts when
<code>$GOROOT</code> is not set explicitly.
<code>$GOROOT_FINAL</code> to the eventual location.
</p>
-<p><code>$GOOS</code> and <code>$GOARCH</code></p>
+<li><code>$GOOS</code> and <code>$GOARCH</code>
<p>
The name of the target operating system and compilation architecture.
These default to the values of <code>$GOHOSTOS</code> and
The valid combinations of <code>$GOOS</code> and <code>$GOARCH</code> are:
<table cellpadding="0">
<tr>
-<th width="50"><th align="left" width="100"><code>$GOOS</code></th> <th align="left" width="100"><code>$GOARCH</code></th> <th align="left"></th>
+<th width="50"></th><th align="left" width="100"><code>$GOOS</code></th> <th align="left" width="100"><code>$GOARCH</code></th>
</tr>
<tr>
<td></td><td><code>darwin</code></td> <td><code>386</code></td>
<td></td><td><code>freebsd</code></td> <td><code>amd64</code></td>
</tr>
<tr>
+<td></td><td><code>freebsd</code></td> <td><code>arm</code></td>
+</tr>
+<tr>
<td></td><td><code>linux</code></td> <td><code>386</code></td>
</tr>
<tr>
<td></td><td><code>netbsd</code></td> <td><code>amd64</code></td>
</tr>
<tr>
+<td></td><td><code>netbsd</code></td> <td><code>arm</code></td>
+</tr>
+<tr>
<td></td><td><code>openbsd</code></td> <td><code>386</code></td>
</tr>
<tr>
<td></td><td><code>plan9</code></td> <td><code>386</code></td>
</tr>
<tr>
+<td></td><td><code>plan9</code></td> <td><code>amd64</code></td>
+</tr>
+<tr>
<td></td><td><code>windows</code></td> <td><code>386</code></td>
</tr>
<tr>
</tr>
</table>
-<p><code>$GOHOSTOS</code> and <code>$GOHOSTARCH</code></p>
+<li><code>$GOHOSTOS</code> and <code>$GOHOSTARCH</code>
<p>
The name of the host operating system and compilation architecture.
These default to the local system's operating system and
<code>arm</code> on an x86 system.
</p>
-<p><code>$GOBIN</code>
+<li><code>$GOBIN</code>
<p>
The location where Go binaries will be installed.
The default is <code>$GOROOT/bin</code>.
installs all commands there.
</p>
-<p><code>$GOARM</code> (arm, default=6)</p>
+<li><code>$GO386</code> (for <code>386</code> only, default is auto-detected
+if built natively, <code>387</code> if not)
+<p>
+This controls the code generated by 8g to use either the 387 floating-point unit
+(set to <code>387</code>) or SSE2 instructions (set to <code>sse2</code>) for
+floating point computations.
+</p>
+<ul>
+ <li><code>GO386=387</code>: use x87 for floating point operations; should support all x86 chips (Pentium MMX or later).
+ <li><code>GO386=sse2</code>: use SSE2 for floating point operations; has better performance than 387, but only available on Pentium 4/Opteron/Athlon 64 or later.
+</ul>
+
+<li><code>$GOARM</code> (for <code>arm</code> only; default is auto-detected if building
+on the target processor, 6 if not)
+<p>
+This sets the ARM floating point co-processor architecture version the run-time
+should target. If you are compiling on the target system, its value will be auto-detected.
+</p>
+<ul>
+ <li><code>GOARM=5</code>: use software floating point; when CPU doesn't have VFP co-processor
+ <li><code>GOARM=6</code>: use VFPv1 only; default if cross compiling; usually ARM11 or better cores (VFPv2 or better is also supported)
+ <li><code>GOARM=7</code>: use VFPv3; usually Cortex-A cores
+</ul>
<p>
-The ARM architecture version the run-time libraries should target.
-Setting <code>$GOARM</code> to 5 causes the linker to emit calls
-to a software floating point implementation instead of using
-hardware floating point support.
+If in doubt, leave this variable unset, and adjust it if required
+when you first run the Go executable.
+The <a href="http://code.google.com/p/go-wiki/wiki/GoArm">GoARM</a> page
+on the <a href="http://code.google.com/p/go-wiki/w/list">Go community wiki</a>
+contains further details regarding Go's ARM support.
</p>
-</blockquote>
+</ul>
<p>
Note that <code>$GOARCH</code> and <code>$GOOS</code> identify the