From: Fred Fish <fnf@specifix.com>
Date: Sun, 8 Dec 1991 02:17:29 +0000 (+0000)
Subject: Use macros to hide some of the ugly casting required in the previously
X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=e59622b438eb6ea7bf4d575fc38d8d05dda5e651;p=deliverable%2Fbinutils-gdb.git

Use macros to hide some of the ugly casting required in the previously
applied fix for pointers with the high bit set.
---

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 9021ee38fd..d440f1e1ea 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+Sat Dec  7 18:13:11 1991  Fred Fish  (fnf at cygnus.com)
+
+	* gmalloc.c:  Use macros to hide some of the ugly casting required
+	in the previously applied fix for pointers with high bits set.
+
 Sat Dec  7 16:49:35 1991  John Gilmore  (gnu at cygnus.com)
 
 	* Makefile.in:  Roll VERSION to 4.3.1.
diff --git a/gdb/gmalloc.c b/gdb/gmalloc.c
index cfd6579597..2c26699f02 100755
--- a/gdb/gmalloc.c
+++ b/gdb/gmalloc.c
@@ -270,6 +270,16 @@ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
 #define BLOCKSIZE	(1 << BLOCKLOG)
 #define BLOCKIFY(SIZE)	(((SIZE) + BLOCKSIZE - 1) / BLOCKSIZE)
 
+/* The difference between two pointers is a signed int.  On machines where
+   the data addresses have the high bit set, we need to ensure that the
+   difference becomes an unsigned int when we are using the address as an
+   integral value.  In addition, when using with the '%' operator, the
+   sign of the result is machine dependent for negative values, so force
+   it to be treated as an unsigned int. */
+
+#define ADDR2UINT(addr)	((unsigned int) ((char *) (addr) - (char *) NULL))
+#define RESIDUAL(addr)	((unsigned int) (ADDR2UINT (addr) % BLOCKSIZE))
+
 /* Determine the amount of memory spanned by the initial heap table
    (not an absolute limit).  */
 #define HEAP		(INT_BIT > 16 ? 4194304 : 65536)
@@ -558,8 +568,7 @@ DEFUN(__free, (ptr), PTR ptr)
 	     it is the first free fragment of this block. */
 	  prev = (struct list *) ptr;
 	  _heapinfo[block].busy.info.frag.nfree = 1;
-	  _heapinfo[block].busy.info.frag.first = (unsigned int)
-	    (((unsigned int)((char *) ptr - (char *) NULL)) % BLOCKSIZE >> type);
+	  _heapinfo[block].busy.info.frag.first = RESIDUAL (ptr) >> type;
 	  prev->next = _fraghead[type].next;
 	  prev->prev = &_fraghead[type];
 	  prev->prev->next = prev;
@@ -656,7 +665,7 @@ DEFUN(align, (size), size_t size)
   unsigned int adj;
 
   result = (*__morecore)(size);
-  adj = (unsigned int) ((unsigned int)((char *) result - (char *) NULL)) % BLOCKSIZE;
+  adj = RESIDUAL (result);
   if (adj != 0)
     {
       adj = BLOCKSIZE - adj;
@@ -769,8 +778,8 @@ DEFUN(malloc, (size), size_t size)
 	    next->next->prev = next->prev;
 	  block = BLOCK(result);
 	  if (--_heapinfo[block].busy.info.frag.nfree != 0)
-	    _heapinfo[block].busy.info.frag.first = (unsigned int)
-	      (((unsigned int)((char *) next->next - (char *) NULL)) % BLOCKSIZE) >> log;
+	    _heapinfo[block].busy.info.frag.first =
+	      RESIDUAL (next->next) >> log;
 
 	  /* Update the statistics.  */
 	  ++_chunks_used;