doc: update install docs for 387->softfloat transition

Fixes #41861

Change-Id: I7aa9370c7762986ee07ba6ff7f6ebda067559f06
Reviewed-on: https://go-review.googlesource.com/c/go/+/260757
Trust: Keith Randall <khr@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

diff --git a/doc/install-source.html b/doc/install-source.html
index 86a4644c0ca9e148d390e7b91c2fbb6c685087d4..c6dc3aed43e2ffba932da54a378301772b34af28 100644 (file)
--- a/doc/install-source.html
+++ b/doc/install-source.html
@@ -666,16 +666,13 @@ For example, you should not set <code>$GOHOSTARCH</code> to
 <code>arm</code> on an x86 system.
 </p>
 
-<li><code>$GO386</code> (for <code>386</code> only, default is auto-detected
-if built on either <code>386</code> or <code>amd64</code>, <code>387</code> otherwise)
+<li><code>$GO386</code> (for <code>386</code> only, defaults to <code>sse2</code>)
 <p>
-This controls the code generated by gc 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.
+This variable controls how gc implements 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>
-       <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.</li>
+       <li><code>GO386=softfloat</code>: use software floating point operations; should support all x86 chips (Pentium MMX or later).</li>
+       <li><code>GO386=sse2</code>: use SSE2 for floating point operations; has better performance but only available on Pentium 4/Opteron/Athlon 64 or later.</li>
 </ul>
 </li>