From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Frank Ch. Eigler" <fche@redhat.com>
To: cgen@sources.redhat.com, binutils@sources.redhat.com
Subject: more cgen disassembly fixes
Date: Mon, 07 May 2001 10:55:00 -0000
Message-id: <20010507135435.A30817@redhat.com>
X-SW-Source: 2001-q2/msg00037.html

Hi -


I'm about to commit the following patch, which goes a little further
in providing disassembly/assembly support to variable/funny length
instruction sets.  Again, no instant opcodes regeneration of working
existing targets is necessary.


2001-05-07  Frank Ch. Eigler  <fche@redhat.com>

	* iformat.scm (compute-insn-base-mask-length): Rewrite to tolerate
	various-base-length instruction sets.

Index: cgen/iformat.scm
===================================================================
RCS file: /cvs/src/src/cgen/iformat.scm,v
retrieving revision 1.2
diff -u -r1.2 iformat.scm
--- iformat.scm	2000/08/22 19:14:30	1.2
+++ iformat.scm	2001/05/07 17:52:32
@@ -90,11 +90,23 @@
 )
 
 ; Given FLD-LIST, compute the base length in bits.
-; Computing the min of state-base-insn-bitsize and the total-length
-; is for [V]LIW instruction sets.
+;
+; For variable length instruction sets, or with cpus with multiple
+; instruction sets, compute the base appropriate for this set of
+; ifields.  Check that ifields are not shared among isas with
+; inconsistent base insn lengths.
 
 (define (compute-insn-base-mask-length fld-list)
-  (min (state-base-insn-bitsize) (compute-insn-length fld-list))
+  (let* ((isa-base-bitsizes
+	  (remove-duplicates
+	   (map isa-base-insn-bitsize
+		(map current-isa-lookup
+		     (collect (lambda (ifld) 
+				(bitset-attr->list (atlist-attr-value (obj-atlist ifld) 'ISA #f)))
+			      fld-list))))))
+    (if (= 1 (length isa-base-bitsizes))
+	(min (car isa-base-bitsizes) (compute-insn-length fld-list))
+	(error "ifields have inconsistent isa/base-insn-size values:" isa-base-bitsizes)))
 )
 
 ; Given FLD-LIST, compute the bitmask of constant values in the base part



2001-05-07  Frank Ch. Eigler  <fche@redhat.com>

	* cgen-dis.in (default_print_insn): Tolerate min<base instructions
	even at end of a section.
	* cgen-ibld.in (extract_normal): Tolerate min!=base!=max instructions
	by ignoring precariously-unpacked insn_value in favor of raw buffer.

Index: opcodes/cgen-dis.in
===================================================================
RCS file: /cvs/src/src/opcodes/cgen-dis.in,v
retrieving revision 1.8
diff -u -r1.8 cgen-dis.in
--- cgen-dis.in	2001/05/04 17:45:19	1.8
+++ cgen-dis.in	2001/05/07 17:52:32
@@ -334,18 +334,27 @@
      disassemble_info *info;
 {
   char buf[CGEN_MAX_INSN_SIZE];
+  int buflen;
   int status;
 
-  /* Read the base part of the insn.  */
+  /* Attempt to read the base part of the insn.  */
+  buflen = cd->base_insn_bitsize / 8;
+  status = (*info->read_memory_func) (pc, buf, buflen, info);
 
-  status = (*info->read_memory_func) (pc, buf, cd->base_insn_bitsize / 8, info);
+  /* Try again with the minimum part, if min < base.  */
+  if (status != 0 && (cd->min_insn_bitsize < cd->base_insn_bitsize))
+    {
+      buflen = cd->min_insn_bitsize / 8;
+      status = (*info->read_memory_func) (pc, buf, buflen, info);
+    }
+
   if (status != 0)
     {
       (*info->memory_error_func) (status, pc, info);
       return -1;
     }
 
-  return print_insn (cd, pc, info, buf, cd->base_insn_bitsize / 8);
+  return print_insn (cd, pc, info, buf, buflen);
 }
 
 /* Main entry point.
Index: opcodes/cgen-ibld.in
===================================================================
RCS file: /cvs/src/src/opcodes/cgen-ibld.in,v
retrieving revision 1.7
diff -u -r1.7 cgen-ibld.in
--- cgen-ibld.in	2001/03/27 21:37:47	1.7
+++ cgen-ibld.in	2001/05/07 17:52:32
@@ -428,9 +428,9 @@
 	word_length = total_length;
     }
 
-  /* Does the value reside in INSN_VALUE?  */
+  /* Does the value reside in INSN_VALUE, and at the right alignment?  */
 
-  if (CGEN_INT_INSN_P || word_offset == 0)
+  if (CGEN_INT_INSN_P || (word_offset == 0 && word_length == total_length))
     {
       if (CGEN_INSN_LSB0_P)
 	value = insn_value >> ((word_offset + start + 1) - length);