[project @ 2002-04-25 18:48:02 by panne]

Ooops, I mixed up PowerPC and SPARC ABIs: On SPARC the stack is always
double-word aligned (quad-word on PowerPC), so the "fully correct"
solution is very probably really correct. => Fixed the comment.  :-}

diff --git a/ghc/rts/Adjustor.c b/ghc/rts/Adjustor.c
index b6887ad..72cc3b6 100644 (file)
--- a/ghc/rts/Adjustor.c
+++ b/ghc/rts/Adjustor.c
@@ -193,9 +193,13 @@ createAdjustor(int cconv, StgStablePtr hptr, StgFunPtr wptr)
     machinery should then work in all cases.  (Or would it?  Perhaps
     it would trash parts of the caller's frame.  Dunno).  
 
-    SUP, 25 Apr 02: Alas, the "fully correct" solution above is only
-    half correct: "%sp has to be 16-byte aligned at all time", the
-    almighty ABI spec says...
+    SUP, 25 Apr 02: We are quite lucky to push a multiple of 8 bytes in
+    front of the existing arguments, because %sp must stay double-word
+    aligned at all times, see: http://www.sparc.org/standards/psABI3rd.pdf
+    Although we extend the *caller's* stack frame, this shouldn't cause
+    any problems for a C-like caller: alloca is implemented similarly, and
+    local variables should be accessed via %fp, not %sp. In a nutshell:
+    This should work. (Famous last words! :-)
   */
     if ((adjustor = stgMallocBytes(4*(8+1), "createAdjustor")) != NULL) {
        unsigned long *const adj_code = (unsigned long *)adjustor;