[PATCH] Add documentation of warning if byte size exceeded

[tcharding]

From: Tobin C. Harding <me@tobin.cc>

GAS throws a warning if an attempt is made to declare data that
exceeds the size allocated when using directives .2byte or .4byte.

Add documentation indicating the warning and the action taken by the
assembler.

---

I see that the patch prior to this one (commit d10ef45) has caused
build fail for someone. Is there anything I can do to help rectify
that issue? 

 gas/doc/as.texinfo | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/gas/doc/as.texinfo b/gas/doc/as.texinfo
index 0a70d7c..6f62511 100644
--- a/gas/doc/as.texinfo
+++ b/gas/doc/as.texinfo
@@ -7347,7 +7347,8 @@ instead of zero.  Using @samp{.zero} in this way would be confusing however.
 
 This directive @code{.2byte}, which is available for ELF targets, expects zero
 or more expressions, separated by commas. Each expression is assembled into the
-next two bytes.
+next two bytes.  If the expression won't fit in 2 bytes, it prints a
+warning message; and just takes the lowest order 2 bytes of the expression.
 
 @node 4byte
 @cindex @code{4byte} directive
@@ -7357,7 +7358,8 @@ next two bytes.
 
 This directive @code{.4byte}, which is available for ELF targets, expects zero
 or more expressions, separated by commas. Each expression is assembled into the
-next four bytes.
+next four bytes.  If the expression won't fit in 4 bytes, it prints a
+warning message; and just takes the lowest order 4 bytes of the expression.
 
 @node 8byte
 @cindex @code{8byte} directive
-- 
2.7.4