[project @ 2003-07-23 16:19:48 by simonmar]

[ghc-hetmet.git] / ghc / includes / StgMacros.h

diff --git a/ghc/includes/StgMacros.h b/ghc/includes/StgMacros.h
index b7e2fc5..2aecd45 100644 (file)
--- a/ghc/includes/StgMacros.h
+++ b/ghc/includes/StgMacros.h
@@ -1,5 +1,5 @@
 /* -----------------------------------------------------------------------------
- * $Id: StgMacros.h,v 1.50 2002/12/11 15:36:39 simonmar Exp $
+ * $Id: StgMacros.h,v 1.53 2003/04/28 10:02:15 simonmar Exp $
  *
  * (c) The GHC Team, 1998-1999
  *
@@ -230,25 +230,41 @@ typedef StgWord StgWordArray[];
 
    The stack frame layout for a RET_DYN is like this:
 
-          some pointers
-          some nonpointers
-          DblReg1-2
-         FltReg1-4
-         R1-8
-         return address
-         liveness mask
-         stg_gen_chk_info
+          some pointers         |-- GET_PTRS(liveness) words
+          some nonpointers      |-- GET_NONPTRS(liveness) words
+                              
+         L1                    \
+          D1-2                  |-- RET_DYN_NONPTR_REGS_SIZE words
+         F1-4                  /
+                              
+         R1-8                  |-- RET_DYN_BITMAP_SIZE words
+                              
+         return address        \
+         liveness mask         |-- StgRetDyn structure
+         stg_gen_chk_info      /
 
    we assume that the size of a double is always 2 pointers (wasting a
    word when it is only one pointer, but avoiding lots of #ifdefs).
 
+   NOTE: if you change the layout of RET_DYN stack frames, then you
+   might also need to adjust the value of RESERVED_STACK_WORDS in
+   Constants.h.
    -------------------------------------------------------------------------- */
 
 // VERY MAGIC CONSTANTS! 
-// must agree with code in HeapStackCheck.c, stg_gen_chk
+// must agree with code in HeapStackCheck.c, stg_gen_chk, and
+// RESERVED_STACK_WORDS in Constants.h.
 //
-#define ALL_NON_PTRS   0xffff
-#define RET_DYN_SIZE   16
+#define RET_DYN_BITMAP_SIZE 8
+#define RET_DYN_NONPTR_REGS_SIZE 10
+#define ALL_NON_PTRS 0xff
+
+// Sanity check that RESERVED_STACK_WORDS is reasonable.  We can't
+// just derive RESERVED_STACK_WORDS because it's used in Haskell code
+// too.
+#if RESERVED_STACK_WORDS != (3 + RET_DYN_BITMAP_SIZE + RET_DYN_NONPTR_REGS_SIZE)
+#error RESERVED_STACK_WORDS may be wrong!
+#endif
 
 #define LIVENESS_MASK(ptr_regs)  (ALL_NON_PTRS ^ (ptr_regs))