diff --git a/doc/asm.html b/doc/asm.html
index 771c493..43382fc 100644
--- a/doc/asm.html
+++ b/doc/asm.html
@@ -350,7 +350,11 @@
 For an assembly function with no pointer results and
 either no local stack frame or no function calls,
 the only requirement is to define a Go prototype for the function
-in a Go source file in the same package.
+in a Go source file in the same package. The name of the assembly
+function must not contain the package name component (for example,
+function <code>Syscall</code> in package <code>syscall</code> should
+use the name <code>·Syscall</code> instead of the equivalent name
+<code>syscall·Syscall</code> in its <code>TEXT</code> directive).
 For more complex situations, explicit annotation is needed.
 These annotations use pseudo-instructions defined in the standard
 <code>#include</code> file <code>funcdata.h</code>.