From 33fef721a111deff1e9a2d8232d68ab8361a266c Mon Sep 17 00:00:00 2001
From: Jan Hubicka <jh@suse.cz>
Date: Tue, 16 Jul 2002 22:31:19 +0000
Subject: [PATCH] 	* tc-i386.c (i386_align_code): Implement x86_64
 neutral code fillers.

---
 gas/ChangeLog        |  4 ++++
 gas/config/tc-i386.c | 49 ++++++++++++++++++++++++++++++--------------
 2 files changed, 38 insertions(+), 15 deletions(-)

diff --git a/gas/ChangeLog b/gas/ChangeLog
index 95f4a61a36..86d2b3d092 100644
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,3 +1,7 @@
+Wed Jul 17 00:30:13 CEST 2002  Jan Hubicka  <jh@suse.cz>
+
+	* tc-i386.c (i386_align_code): Implement x86_64 neutral code fillers.
+
 2002-07-16  Moritz Jodeit  <moritz@jodeit.org>
 
 	* config/tc-z8k.c (build_bytes): Correct order of memset args.
diff --git a/gas/config/tc-i386.c b/gas/config/tc-i386.c
index c7dbfbdfa6..85611de142 100644
--- a/gas/config/tc-i386.c
+++ b/gas/config/tc-i386.c
@@ -521,26 +521,45 @@ i386_align_code (fragP, count)
     f32_15, f32_15, f32_15, f32_15, f32_15, f32_15, f32_15
   };
 
-  /* ??? We can't use these fillers for x86_64, since they often kills the
-     upper halves.  Solve later.  */
-  if (flag_code == CODE_64BIT)
-    count = 1;
+  if (count <= 0 || count > 15)
+    return;
 
-  if (count > 0 && count <= 15)
+  /* The recommended way to pad 64bit code is to use NOPs preceded by
+     maximally four 0x66 prefixes.  Balance the size of nops.  */
+  if (flag_code == CODE_64BIT)
     {
-      if (flag_code == CODE_16BIT)
+      int i;
+      int nnops = (count + 3) / 4;
+      int len = count / nnops;
+      int remains = count - nnops * len;
+      int pos = 0;
+
+      for (i = 0; i < remains; i++)
 	{
-	  memcpy (fragP->fr_literal + fragP->fr_fix,
-		  f16_patt[count - 1], count);
-	  if (count > 8)
-	    /* Adjust jump offset.  */
-	    fragP->fr_literal[fragP->fr_fix + 1] = count - 2;
+	  memset (fragP->fr_literal + fragP->fr_fix + pos, 0x66, len);
+	  fragP->fr_literal[fragP->fr_fix + pos + len] = 0x90;
+	  pos += len + 1;
+	}
+      for (; i < nnops; i++)
+	{
+	  memset (fragP->fr_literal + fragP->fr_fix + pos, 0x66, len - 1);
+	  fragP->fr_literal[fragP->fr_fix + pos + len - 1] = 0x90;
+	  pos += len;
 	}
-      else
-	memcpy (fragP->fr_literal + fragP->fr_fix,
-		f32_patt[count - 1], count);
-      fragP->fr_var = count;
     }
+  else
+    if (flag_code == CODE_16BIT)
+      {
+	memcpy (fragP->fr_literal + fragP->fr_fix,
+		f16_patt[count - 1], count);
+	if (count > 8)
+	  /* Adjust jump offset.  */
+	  fragP->fr_literal[fragP->fr_fix + 1] = count - 2;
+      }
+    else
+      memcpy (fragP->fr_literal + fragP->fr_fix,
+	      f32_patt[count - 1], count);
+  fragP->fr_var = count;
 }
 
 static INLINE unsigned int