Patch: Add a stop bit in alignment for alloc.

[H. J. Lu]

On Mon, Mar 01, 2004 at 03:18:38PM -0800, Jim Wilson wrote:
> 
> We could save frag_now in ia64_md_do_align.  The var frag would then be
> either that frag, or the next one if the existing frag did not have
> enough room left.
> 
> insn_group_break would then check to see if the next frag after the
> saved var frag is the current one, in which case the saved var frag has
> to end with a stop bit.

Here is the patch. We only need to check it in md_assemble when we see
IA64_OPCODE_FIRST. We don't need a stop bit if the next instruction
is not one of those IA64_OPCODE_FIRST ones.


H.J.
-------------- next part --------------
2004-03-02  H.J. Lu  <hongjiu.lu@intel.com>

	* config/tc-ia64.c (align_frag): New.
	(md_assemble): Set the tc_frag_data field in align_frag for
	IA64_OPCODE_FIRST instructions.
	(ia64_md_do_align): Set align_frag.
	(ia64_handle_align): Add a stop bit if needed.

	* config/tc-ia64.h (TC_FRAG_TYPE): New.
	(TC_FRAG_INIT): New.

--- gas/config/tc-ia64.c.alloc	2004-02-24 09:32:19.000000000 -0800
+++ gas/config/tc-ia64.c	2004-03-02 12:22:09.000000000 -0800
@@ -636,6 +636,9 @@ static struct gr {
   valueT value;
 } gr_values[128] = {{ 1, 0, 0 }};
 
+/* Remember the alignment frag.  */
+static fragS *align_frag;
+
 /* These are the routines required to output the various types of
    unwind records.  */
 
@@ -9990,7 +9993,16 @@ md_assemble (str)
   flags = idesc->flags;
 
   if ((flags & IA64_OPCODE_FIRST) != 0)
-    insn_group_break (1, 0, 0);
+    {
+      /* The alignment frag has to end with a stop bit only if the
+	 next instruction after the alignment directive has to be
+	 the first instruction in an instruction group.  */
+      if (align_frag && align_frag->fr_next == frag_now)
+	align_frag->tc_frag_data = 1;
+
+      insn_group_break (1, 0, 0);
+    }
+  align_frag = NULL;
 
   if ((flags & IA64_OPCODE_NO_PRED) != 0 && qp_regno != 0)
     {
@@ -10808,6 +10820,8 @@ ia64_md_do_align (n, fill, len, max)
      int len ATTRIBUTE_UNUSED;
      int max ATTRIBUTE_UNUSED;
 {
+  /* The current frag is an alignment frag.  */
+  align_frag = frag_now;
   if (subseg_text_p (now_seg))
     ia64_flush_insns ();
 }
@@ -10823,13 +10837,20 @@ ia64_handle_align (fragp)
   static const unsigned char le_nop[]
     = { 0x0c, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00,
 	0x00, 0x02, 0x00, 0x00, 0x00, 0x00, 0x04, 0x00};
+  static const unsigned char le_nop_stop[]
+    = { 0x0d, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00,
+	0x00, 0x02, 0x00, 0x00, 0x00, 0x00, 0x04, 0x00};
 
   int bytes;
   char *p;
+  const unsigned char *nop;
 
   if (fragp->fr_type != rs_align_code)
     return;
 
+  /* Check if this frag has to end with a stop bit.  */
+  nop = fragp->tc_frag_data ? le_nop_stop : le_nop;
+
   bytes = fragp->fr_next->fr_address - fragp->fr_address - fragp->fr_fix;
   p = fragp->fr_literal + fragp->fr_fix;
 
@@ -10845,7 +10866,7 @@ ia64_handle_align (fragp)
     }
 
   /* Instruction bundles are always little-endian.  */
-  memcpy (p, le_nop, 16);
+  memcpy (p, nop, 16);
   fragp->fr_var = 16;
 }
 
--- gas/config/tc-ia64.h.alloc	2004-03-01 09:05:22.000000000 -0800
+++ gas/config/tc-ia64.h	2004-03-02 12:11:27.000000000 -0800
@@ -159,6 +159,10 @@ extern void ia64_convert_frag (fragS *);
 #define TC_DWARF2_EMIT_OFFSET		ia64_dwarf2_emit_offset
 #define tc_check_label(l)		ia64_check_label (l)
 
+/* Record if an alignment frag should end with a stop bit.  */
+#define TC_FRAG_TYPE			int
+#define TC_FRAG_INIT(FRAGP)		do {(FRAGP)->tc_frag_data = 0;}while (0)
+
 #define MAX_MEM_FOR_RS_ALIGN_CODE  (15 + 16)
 
 #define WORKING_DOT_WORD	/* don't do broken word processing for now */