va_list: c4x

[Richard Henderson]

This has got to be the simplest va_arg implementation in existance. 
Unsurprisingly, on simple tests it produces identical output as va-c4x.h.  


r~


	* c4x.h (EXPAND_BUILTIN_VA_ARG): New.
	* c4x.c (c4x_va_arg): New.

Index: c4x/c4x.c
===================================================================
RCS file: /egcs/carton/cvsfiles/egcs/gcc/config/c4x/c4x.c,v
retrieving revision 1.28
diff -c -p -d -r1.28 c4x.c
*** c4x.c	1999/06/09 03:47:21	1.28
--- c4x.c	1999/07/26 06:39:02
*************** c4x_function_arg (cum, mode, type, named
*** 572,577 ****
--- 572,592 ----
      return NULL_RTX;
  }
  
+ /* C[34]x arguments grow in weird ways (downwards) that the standard
+    varargs stuff can't handle. */
+ 
+ rtx
+ c4x_va_arg (valist, type)
+      tree valist, type;
+ {
+   tree t;
+ 
+   t = build (PREDECREMENT_EXPR, TREE_TYPE (valist), valist,
+ 	     build_int_2 (int_size_in_bytes (type), 0));
+   TREE_SIDE_EFFECTS (t) = 1;
+ 
+   return expand_expr (t, NULL_RTX, Pmode, EXPAND_NORMAL);
+ }
  
  static int
  c4x_isr_reg_used_p (regno)
Index: c4x/c4x.h
===================================================================
RCS file: /egcs/carton/cvsfiles/egcs/gcc/config/c4x/c4x.h,v
retrieving revision 1.21
diff -c -p -d -r1.21 c4x.h
*** c4x.h	1999/06/09 03:47:22	1.21
--- c4x.h	1999/07/26 06:39:02
*************** extern struct rtx_def *c4x_function_arg(
*** 1157,1162 ****
--- 1157,1166 ----
  #define DEFAULT_PCC_STRUCT_RETURN	0
  #define STRUCT_VALUE_REGNUM		AR0_REGNO	/* AR0 */
  
+ /* Varargs handling.  */
+ 
+ #define EXPAND_BUILTIN_VA_ARG(valist, type) \
+   c4x_va_arg (valist, type)
  
  /* Function Entry and Exit  */