PATCH: document MD_INIT_BUILTINS and MD_EXPAND_BUILTIN

[Lars Brinkhoff]

An attempt to document MD_INIT_BUILTINS and MD_EXPAND_BUILTIN.
Corrections welcome.

2001-02-01  lars brinkhoff  <lars@nocrew.org>

        * tm.texi (MD_INIT_BUILTINS): document.
        (MD_EXPAND_BUILTIN): likewise.

Index: tm.texi
===================================================================
RCS file: /cvs/gcc/gcc/gcc/tm.texi,v
retrieving revision 1.168
diff -u -r1.168 tm.texi
--- tm.texi     2001/01/30 05:42:06     1.168
+++ tm.texi     2001/02/01 10:16:15
@@ -8372,3 +8372,18 @@
 converting code to conditional execution in the basic blocks
 @code{TEST_BB}, @code{THEN_BB}, @code{ELSE_BB}, and @code{JOIN_BB}.
 @end table
+
+@findex MD_INIT_BUILTINS
+@item MD_INIT_BUILTINS
+If defined, a C statement (sans semicolon) to define machine dependent
+built-in functions.  A built-in function can be defined by calling
+@code{builtin_function}.
+
+@findex MD_EXPAND_BUILTIN
+@item MD_EXPAND_BUILTIN (@var{exp}, @var{target}, @var{subtarget}, @var{mode},
@var{ignore})
+If defined, a C statement (sans semicolon) to expand an expression
+@var{exp} that calls a built-in function, with result going to
+@var{target} if that's convenient (and in mode @var{mode} if that's
+convenient).  @var{subtarget} may be used as the target for computing
+one of @var{exp}'s operands.  @var{ignore} is nonzero if the value is to
+be ignored.