2002-08-19 Elena Zannoni <ezannoni@redhat.com>

[deliverable/binutils-gdb.git] / opcodes / cgen-dis.c

diff --git a/opcodes/cgen-dis.c b/opcodes/cgen-dis.c
index b4297bb44d7e7372dff3c4f55da9ae025a732c66..881ee1470f32ff98b074c702249d448bec8d509b 100644 (file)
--- a/opcodes/cgen-dis.c
+++ b/opcodes/cgen-dis.c
@@ -1,6 +1,6 @@
 /* CGEN generic disassembler support code.
 
 /* CGEN generic disassembler support code.
 

-   Copyright 1996, 1997, 1998, 1999, 2000, 2001
+   Copyright 1996, 1997, 1998, 1999, 2000, 2001, 2002

    Free Software Foundation, Inc.
 
    This file is part of the GNU Binutils and GDB, the GNU debugger.
    Free Software Foundation, Inc.
 
    This file is part of the GNU Binutils and GDB, the GNU debugger.


@@ -27,6 +27,66 @@
 #include "symcat.h"
 #include "opcode/cgen.h"
 
 #include "symcat.h"
 #include "opcode/cgen.h"
 

+static CGEN_INSN_LIST *  hash_insn_array      PARAMS ((CGEN_CPU_DESC, const CGEN_INSN *, int, int, CGEN_INSN_LIST **, CGEN_INSN_LIST *));
+static CGEN_INSN_LIST *  hash_insn_list       PARAMS ((CGEN_CPU_DESC, const CGEN_INSN_LIST *, CGEN_INSN_LIST **, CGEN_INSN_LIST *));
+static void              build_dis_hash_table PARAMS ((CGEN_CPU_DESC));
+static int              count_decodable_bits PARAMS ((const CGEN_INSN *));
+static void             add_insn_to_hash_chain PARAMS ((CGEN_INSN_LIST *,
+                                                        const CGEN_INSN *,
+                                                        CGEN_INSN_LIST **,
+                                                        unsigned int));
+
+/* Return the number of decodable bits in this insn.  */
+static int
+count_decodable_bits (insn)
+  const CGEN_INSN *insn;
+{
+  unsigned mask = CGEN_INSN_BASE_MASK (insn);
+  int bits = 0;
+  int m;
+  for (m = 1; m != 0; m <<= 1)
+    {
+      if (mask & m)
+       ++bits;
+    }
+  return bits;
+}
+
+/* Add an instruction to the hash chain.  */     
+static void
+add_insn_to_hash_chain (hentbuf, insn, htable, hash)
+     CGEN_INSN_LIST *hentbuf;
+     const CGEN_INSN *insn;
+     CGEN_INSN_LIST **htable;
+     unsigned int hash;
+{
+  CGEN_INSN_LIST *current_buf;
+  CGEN_INSN_LIST *previous_buf;
+  int insn_decodable_bits;
+
+  /* Add insns sorted by the number of decodable bits, in decreasing order.
+     This ensures that any insn which is a special case of another will be
+     checked first.  */
+  insn_decodable_bits = count_decodable_bits (insn);
+  previous_buf = NULL;
+  for (current_buf = htable[hash]; current_buf != NULL;
+       current_buf = current_buf->next)
+    {
+      int current_decodable_bits = count_decodable_bits (current_buf->insn);
+      if (insn_decodable_bits >= current_decodable_bits)
+       break;
+      previous_buf = current_buf;
+    }
+
+  /* Now insert the new insn.  */
+  hentbuf->insn = insn;
+  hentbuf->next = current_buf;
+  if (previous_buf == NULL)
+    htable[hash] = hentbuf;
+  else
+    previous_buf->next = hentbuf;
+}
+

 /* Subroutine of build_dis_hash_table to add INSNS to the hash table.
 
    COUNT is the number of elements in INSNS.
 /* Subroutine of build_dis_hash_table to add INSNS to the hash table.
 
    COUNT is the number of elements in INSNS.


@@ -70,9 +130,7 @@ hash_insn_array (cd, insns, count, entsize, htable, hentbuf)
                    CGEN_INSN_MASK_BITSIZE (insn),
                    big_p);
       hash = (* cd->dis_hash) (buf, value);
                    CGEN_INSN_MASK_BITSIZE (insn),
                    big_p);
       hash = (* cd->dis_hash) (buf, value);

-      hentbuf->next = htable[hash];
-      hentbuf->insn = insn;
-      htable[hash] = hentbuf;
+      add_insn_to_hash_chain (hentbuf, insn, htable, hash);

     }
 
   return hentbuf;
     }
 
   return hentbuf;


@@ -110,9 +168,7 @@ hash_insn_list (cd, insns, htable, hentbuf)
                   CGEN_INSN_MASK_BITSIZE (ilist->insn),
                   big_p);
       hash = (* cd->dis_hash) (buf, value);
                   CGEN_INSN_MASK_BITSIZE (ilist->insn),
                   big_p);
       hash = (* cd->dis_hash) (buf, value);

-      hentbuf->next = htable [hash];
-      hentbuf->insn = ilist->insn;
-      htable [hash] = hentbuf;
+      add_insn_to_hash_chain (hentbuf, ilist->insn, htable, hash);

     }
 
   return hentbuf;
     }
 
   return hentbuf;