stormy-abi: Updates to varargs descriptions.

        * config/stormy16/stormy-abi:  Updates to varargs descriptions.
        * config/stormy16/stormy16.c (stormy16_build_va_list):  Reverse
        base and count fields.
        (stormy16_expand_builtin_va_start):  last_reg_count changed to
        size_of_reg_args.  Use count + size in first comparison.

From-SVN: r46365

gcc/ChangeLog

+2001-10-19  Catherine Moore  <clm@redhat.com>
+
+        * config/stormy16/stormy-abi:  Updates to varargs descriptions.
+        * config/stormy16/stormy16.c (stormy16_build_va_list):  Reverse
+        base and count fields.
+        (stormy16_expand_builtin_va_start):  last_reg_count changed to
+        size_of_reg_args.  Use count + size in first comparison.
+
 Fri Oct 19 15:24:39 2001  Richard Kenner  <kenner@vlsi1.ultra.nyu.edu>
 
 	* langhooks.h (LANG_HOOKS_HONOR_READONLY): New macro.

gcc/config/stormy16/stormy-abi

@@ -70,11 +70,13 @@ Both fields are 16 bits.  An argument of size N bytes
 (N will be even) is accessed as if by the following code:
 
 char *result;
-if (count + N > 16)
+/* count = #bytes non-variable arguments */
+/* 12 = #bytes for register arguments */
+if (count + N > 12)
   {
-    if (count < 16)
-      count = 16;
-    result = base - (count + N - 16 + 4);
+    if (count < 12)
+      count = 12;
+    result = base - (count + N - 12 + 4);
   }
 else
   {
@@ -98,8 +100,8 @@ SP ->
 	r3
 count->	r2
 	Return address (two words)
-	9th procedure parameter word
-	10th procedure parameter word
+	7th procedure parameter word
+	8th procedure parameter word
 	...
 	last procedure parameter word
 

gcc/config/stormy16/stormy16.c

@@ -1131,9 +1131,9 @@ stormy16_build_va_list ()
   record = make_lang_type (RECORD_TYPE);
   type_decl = build_decl (TYPE_DECL, get_identifier ("__va_list_tag"), record);
 
-  f_2 = build_decl (FIELD_DECL, get_identifier ("base"),
+  f_1 = build_decl (FIELD_DECL, get_identifier ("base"),
 		      ptr_type_node);
-  f_1 = build_decl (FIELD_DECL, get_identifier ("count"), 
+  f_2 = build_decl (FIELD_DECL, get_identifier ("count"), 
 		      unsigned_type_node);
 
   DECL_FIELD_CONTEXT (f_1) = record;
@@ -1186,7 +1186,9 @@ stormy16_expand_builtin_va_start (stdarg_p, valist, nextarg)
 }
 
 /* Implement the stdarg/varargs va_arg macro.  VALIST is the variable
-   of type va_list as a tree, TYPE is the type passed to va_arg.  */
+   of type va_list as a tree, TYPE is the type passed to va_arg.
+   Note:  This algorithm is documented in stormy-abi.  */
+   
 rtx
 stormy16_expand_builtin_va_arg (valist, type)
      tree valist;
@@ -1197,8 +1199,9 @@ stormy16_expand_builtin_va_arg (valist, type)
   rtx count_rtx, addr_rtx, r;
   rtx lab_gotaddr, lab_fromstack;
   tree t;
-  int size, last_reg_count;
+  int size, size_of_reg_args;
   tree size_tree, count_plus_size;
+  rtx count_plus_size_rtx;
   
   f_base = TYPE_FIELDS (va_list_type_node);
   f_count = TREE_CHAIN (f_base);
@@ -1209,14 +1212,17 @@ stormy16_expand_builtin_va_arg (valist, type)
   size = PUSH_ROUNDING (int_size_in_bytes (type));
   size_tree = round_up (size_in_bytes (type), UNITS_PER_WORD);
   
-  last_reg_count = NUM_ARGUMENT_REGISTERS * UNITS_PER_WORD - size;
+  size_of_reg_args = NUM_ARGUMENT_REGISTERS * UNITS_PER_WORD;
 
   count_rtx = expand_expr (count, NULL_RTX, HImode, EXPAND_NORMAL);
   lab_gotaddr = gen_label_rtx ();
   lab_fromstack = gen_label_rtx ();
   addr_rtx = gen_reg_rtx (Pmode);
-  emit_cmp_and_jump_insns (count_rtx, GEN_INT (last_reg_count),
-			  GTU, const1_rtx, HImode, 1, 1, lab_fromstack);
+
+  count_plus_size = build (PLUS_EXPR, TREE_TYPE (count), count, size_tree);
+  count_plus_size_rtx = expand_expr (count_plus_size, NULL_RTX, HImode, EXPAND_NORMAL);
+  emit_cmp_and_jump_insns (count_plus_size_rtx, GEN_INT (size_of_reg_args),
+			   GTU, const1_rtx, HImode, 1, 1, lab_fromstack);
   
   t = build (PLUS_EXPR, ptr_type_node, base, count);
   r = expand_expr (t, addr_rtx, Pmode, EXPAND_NORMAL);