include/opcode/

	* mips.h (OP_OPTIONAL_REG): New mips_operand_type.
	(mips_optional_operand_p): New function.

opcodes/
	* mips-formats.h (OPTIONAL_REG, OPTIONAL_MAPPED_REG): New macros.
	* micromips-opc.c (decode_micromips_operand): Use OPTIONAL_REG
	and OPTIONAL_MAPPED_REG.
	* mips-opc.c (decode_mips_operand): Likewise.
	* mips16-opc.c (decode_mips16_operand): Likewise.
	* mips-dis.c (print_insn_arg): Handle OP_OPTIONAL_REG.

gas/
	* config/tc-mips.c (operand_reg_mask, match_operand): Handle
	OP_OPTIONAL_REG.
	(mips_ip, mips16_ip): Use mips_optional_operand_p to check
	for optional operands.

10 files changed, 96 insertions, 68 deletions

diff --git a/gas/ChangeLog b/gas/ChangeLog
index f0ca044..92ad6f6 100644
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,3 +1,10 @@
+2013-08-19  Richard Sandiford  <rdsandiford@googlemail.com>
+
+	* config/tc-mips.c (operand_reg_mask, match_operand): Handle
+	OP_OPTIONAL_REG.
+	(mips_ip, mips16_ip): Use mips_optional_operand_p to check
+	for optional operands.
+
 2013-08-16  Alan Modra  <amodra@gmail.com>
 
 	* config/tc-ppc.c (ppc_elf_cons): Allow @l and other reloc
diff --git a/gas/config/tc-mips.c b/gas/config/tc-mips.c
index f35dbe0..814b218 100644
--- a/gas/config/tc-mips.c
+++ b/gas/config/tc-mips.c
@@ -3868,6 +3868,7 @@ operand_reg_mask (const struct mips_cl_insn *insn,
       abort ();
 
     case OP_REG:
+    case OP_OPTIONAL_REG:
       {
 	const struct mips_reg_operand *reg_op;
 
@@ -5283,6 +5284,7 @@ match_operand (struct mips_arg_info *arg,
       return match_msb_operand (arg, operand);
 
     case OP_REG:
+    case OP_OPTIONAL_REG:
       return match_reg_operand (arg, operand);
 
     case OP_REG_PAIR:
@@ -12393,7 +12395,6 @@ mips_ip (char *str, struct mips_cl_insn *ip)
   const struct mips_operand *operand;
   struct mips_arg_info arg;
   struct mips_operand_token *tokens;
-  bfd_boolean optional_reg;
   unsigned int opcode_extra;
 
   insn_error = NULL;
@@ -12522,17 +12523,17 @@ mips_ip (char *str, struct mips_cl_insn *ip)
 	      /* Handle unary instructions in which only one operand is given.
 		 The source is then the same as the destination.  */
 	      if (arg.opnum == 1 && *args == ',')
-		switch (args[1])
-		  {
-		  case 'r':
-		  case 'v':
-		  case 'w':
-		  case 'W':
-		  case 'V':
-		    arg.token = tokens;
-		    arg.argnum = 1;
-		    continue;
-		  }
+		{
+		  operand = (mips_opts.micromips
+			     ? decode_micromips_operand (args + 1)
+			     : decode_mips_operand (args + 1));
+		  if (operand && mips_optional_operand_p (operand))
+		    {
+		      arg.token = tokens;
+		      arg.argnum = 1;
+		      continue;
+		    }
+		}
 
 	      /* Treat elided base registers as $0.  */
 	      if (strcmp (args, "(b)") == 0)
@@ -12593,7 +12594,6 @@ mips_ip (char *str, struct mips_cl_insn *ip)
 	     other operands.  */
 	  arg.opnum += 1;
 	  arg.lax_max = FALSE;
-	  optional_reg = FALSE;
 	  switch (*args)
 	    {
 	    case '+':
@@ -12668,17 +12668,6 @@ mips_ip (char *str, struct mips_cl_insn *ip)
 		arg.soft_match = FALSE;
 	      break;
 
-	    case 'r':
-	    case 'v':
-	    case 'w':
-	    case 'W':
-	    case 'V':
-	      /* We have already matched a comma by this point, so the register
-		 is only optional if there is another operand to come.  */
-	      gas_assert (arg.opnum == 2);
-	      optional_reg = (args[1] == ',');
-	      break;
-
 	    case 'I':
 	      if (match_const_int (&arg, &imm_expr.X_add_number, 0))
 		imm_expr.X_op = O_constant;
@@ -12766,16 +12755,6 @@ mips_ip (char *str, struct mips_cl_insn *ip)
 	      c = args[1];
 	      switch (c)
 		{
-		case 't':
-		case 'c':
-		case 'e':
-		  /* We have already matched a comma by this point,
-		     so the register is only optional if there is another
-		     operand to come.  */
-		  gas_assert (arg.opnum == 2);
-		  optional_reg = (args[2] == ',');
-		  break;
-
 		case 'D':
 		case 'E':
 		  if (!forced_insn_length)
@@ -12795,7 +12774,12 @@ mips_ip (char *str, struct mips_cl_insn *ip)
 	  if (!operand)
 	    abort ();
 
-	  if (optional_reg
+	  /* Skip prefixes.  */
+	  if (*args == '+' || *args == 'm')
+	    args++;
+
+	  if (mips_optional_operand_p (operand)
+	      && args[1] == ','
 	      && (arg.token[0].type != OT_REG
 		  || arg.token[1].type == OT_END))
 	    {
@@ -12808,10 +12792,6 @@ mips_ip (char *str, struct mips_cl_insn *ip)
 	  if (!match_operand (&arg, operand))
 	    break;
 
-	  /* Skip prefixes.  */
-	  if (*args == '+' || *args == 'm')
-	    args++;
-
 	  continue;
 	}
       /* Args don't match.  */
@@ -12848,7 +12828,6 @@ mips16_ip (char *str, struct mips_cl_insn *ip)
   const struct mips_operand *ext_operand;
   struct mips_arg_info arg;
   struct mips_operand_token *tokens;
-  bfd_boolean optional_reg;
 
   insn_error = NULL;
 
@@ -12961,14 +12940,15 @@ mips16_ip (char *str, struct mips_cl_insn *ip)
 	      /* Handle unary instructions in which only one operand is given.
 		 The source is then the same as the destination.  */
 	      if (arg.opnum == 1 && *args == ',')
-		switch (args[1])
-		  {
-		  case 'v':
-		  case 'w':
-		    arg.token = tokens;
-		    arg.argnum = 1;
-		    continue;
-		  }
+		{
+		  operand = decode_mips16_operand (args[1], FALSE);
+		  if (operand && mips_optional_operand_p (operand))
+		    {
+		      arg.token = tokens;
+		      arg.argnum = 1;
+		      continue;
+		    }
+		}
 
 	      /* Fail the match if there were too few operands.  */
 	      if (*args)
@@ -13020,15 +13000,9 @@ mips16_ip (char *str, struct mips_cl_insn *ip)
 	    }
 
 	  arg.opnum += 1;
-	  optional_reg = FALSE;
 	  c = *args;
 	  switch (c)
 	    {
-	    case 'v':
-	    case 'w':
-	      optional_reg = (args[1] == ',');
-	      break;
-
 	    case 'p':
 	    case 'q':
 	    case 'A':
@@ -13094,7 +13068,8 @@ mips16_ip (char *str, struct mips_cl_insn *ip)
 		}
 	    }
 
-	  if (optional_reg
+	  if (mips_optional_operand_p (operand)
+	      && args[1] == ','
 	      && (arg.token[0].type != OT_REG
 		  || arg.token[1].type == OT_END))
 	    {
diff --git a/include/opcode/ChangeLog b/include/opcode/ChangeLog
index cdf578a..19fd1b3 100644
--- a/include/opcode/ChangeLog
+++ b/include/opcode/ChangeLog
@@ -1,3 +1,8 @@
+2013-08-19  Richard Sandiford  <rdsandiford@googlemail.com>
+
+	* mips.h (OP_OPTIONAL_REG): New mips_operand_type.
+	(mips_optional_operand_p): New function.
+
 2013-08-04  Jürgen Urban  <JuergenUrban@gmx.de>
 	    Richard Sandiford  <rdsandiford@googlemail.com>
 
diff --git a/include/opcode/mips.h b/include/opcode/mips.h
index ae6983b..6860fa7 100644
--- a/include/opcode/mips.h
+++ b/include/opcode/mips.h
@@ -346,6 +346,10 @@ enum mips_operand_type {
   /* Described by mips_reg_operand.  */
   OP_REG,
 
+  /* Like OP_REG, but can be omitted if the register is the same as the
+     previous operand.  */
+  OP_OPTIONAL_REG,
+
   /* Described by mips_reg_pair_operand.  */
   OP_REG_PAIR,
 
@@ -574,6 +578,15 @@ struct mips_pcrel_operand
   unsigned int flip_isa_bit : 1;
 };
 
+/* Return true if the assembly syntax allows OPERAND to be omitted.  */
+
+static inline bfd_boolean
+mips_optional_operand_p (const struct mips_operand *operand)
+{
+  return (operand->type == OP_OPTIONAL_REG
+	  || operand->type == OP_REPEAT_PREV_REG);
+}
+
 /* Return a version of INSN in which the field specified by OPERAND
    has value UVAL.  */
 
diff --git a/opcodes/ChangeLog b/opcodes/ChangeLog
index 58cd107..b4840ee 100644
--- a/opcodes/ChangeLog
+++ b/opcodes/ChangeLog
@@ -1,3 +1,12 @@
+2013-08-19  Richard Sandiford  <rdsandiford@googlemail.com>
+
+	* mips-formats.h (OPTIONAL_REG, OPTIONAL_MAPPED_REG): New macros.
+	* micromips-opc.c (decode_micromips_operand): Use OPTIONAL_REG
+	and OPTIONAL_MAPPED_REG.
+	* mips-opc.c (decode_mips_operand): Likewise.
+	* mips16-opc.c (decode_mips16_operand): Likewise.
+	* mips-dis.c (print_insn_arg): Handle OP_OPTIONAL_REG.
+
 2013-08-19  H.J. Lu  <hongjiu.lu@intel.com>
 
 	* i386-dis.c (PREFIX_EVEX_0F3A3E): Removed.
diff --git a/opcodes/micromips-opc.c b/opcodes/micromips-opc.c
index 5243d4c..33dd57e 100644
--- a/opcodes/micromips-opc.c
+++ b/opcodes/micromips-opc.c
@@ -53,9 +53,9 @@ decode_micromips_operand (const char *p)
 	{
 	case 'a': MAPPED_REG (0, 0, GP, reg_28_map);
 	case 'b': MAPPED_REG (3, 23, GP, reg_m16_map);
-	case 'c': MAPPED_REG (3, 4, GP, reg_m16_map);
+	case 'c': OPTIONAL_MAPPED_REG (3, 4, GP, reg_m16_map);
 	case 'd': MAPPED_REG (3, 7, GP, reg_m16_map);
-	case 'e': MAPPED_REG (3, 1, GP, reg_m16_map);
+	case 'e': OPTIONAL_MAPPED_REG (3, 1, GP, reg_m16_map);
 	case 'f': MAPPED_REG (3, 3, GP, reg_m16_map);
 	case 'g': MAPPED_REG (3, 0, GP, reg_m16_map);
 	case 'h': REG_PAIR (3, 7, GP, reg_h_map);
@@ -144,7 +144,7 @@ decode_micromips_operand (const char *p)
     case 'R': REG (5, 6, FP);
     case 'S': REG (5, 16, FP);
     case 'T': REG (5, 21, FP);
-    case 'V': REG (5, 16, FP);
+    case 'V': OPTIONAL_REG (5, 16, FP);
 
     case 'a': JUMP (26, 0, 1);
     case 'b': REG (5, 16, GP);
@@ -158,12 +158,12 @@ decode_micromips_operand (const char *p)
     case 'o': SINT (16, 0);
     case 'p': BRANCH (16, 0, 1);
     case 'q': HINT (10, 6);
-    case 'r': REG (5, 16, GP);
+    case 'r': OPTIONAL_REG (5, 16, GP);
     case 's': REG (5, 16, GP);
     case 't': REG (5, 21, GP);
     case 'u': HINT (16, 0);
-    case 'v': REG (5, 16, GP);
-    case 'w': REG (5, 21, GP);
+    case 'v': OPTIONAL_REG (5, 16, GP);
+    case 'w': OPTIONAL_REG (5, 21, GP);
     case 'y': REG (5, 6, GP);
     case 'z': MAPPED_REG (0, 0, GP, reg_0_map);
     }
diff --git a/opcodes/mips-dis.c b/opcodes/mips-dis.c
index 1d1c724..dce4d86 100644
--- a/opcodes/mips-dis.c
+++ b/opcodes/mips-dis.c
@@ -1042,6 +1042,7 @@ print_insn_arg (struct disassemble_info *info,
       break;
 
     case OP_REG:
+    case OP_OPTIONAL_REG:
       {
 	const struct mips_reg_operand *reg_op;
 
diff --git a/opcodes/mips-formats.h b/opcodes/mips-formats.h
index 49a0623..4b5aaaf 100644
--- a/opcodes/mips-formats.h
+++ b/opcodes/mips-formats.h
@@ -69,6 +69,14 @@
     return &op.root; \
   }
 
+#define OPTIONAL_REG(SIZE, LSB, BANK) \
+  { \
+    static const struct mips_reg_operand op = { \
+      { OP_OPTIONAL_REG, SIZE, LSB }, OP_REG_##BANK, 0 \
+    }; \
+    return &op.root; \
+  }
+
 #define MAPPED_REG(SIZE, LSB, BANK, MAP) \
   { \
     typedef char ATTRIBUTE_UNUSED \
@@ -79,6 +87,16 @@
     return &op.root; \
   }
 
+#define OPTIONAL_MAPPED_REG(SIZE, LSB, BANK, MAP) \
+  { \
+    typedef char ATTRIBUTE_UNUSED \
+      static_assert[(1 << (SIZE)) == ARRAY_SIZE (MAP)]; \
+    static const struct mips_reg_operand op = { \
+      { OP_OPTIONAL_REG, SIZE, LSB }, OP_REG_##BANK, MAP \
+    }; \
+    return &op.root; \
+  }
+
 #define REG_PAIR(SIZE, LSB, BANK, MAP) \
   { \
     typedef char ATTRIBUTE_UNUSED \
diff --git a/opcodes/mips-opc.c b/opcodes/mips-opc.c
index feb96a5..7fdc938 100644
--- a/opcodes/mips-opc.c
+++ b/opcodes/mips-opc.c
@@ -134,8 +134,8 @@ decode_mips_operand (const char *p)
     case 'S': REG (5, 11, FP);
     case 'T': REG (5, 16, FP);
     case 'U': SPECIAL (10, 11, CLO_CLZ_DEST);
-    case 'V': REG (5, 11, FP);
-    case 'W': REG (5, 16, FP);
+    case 'V': OPTIONAL_REG (5, 11, FP);
+    case 'W': OPTIONAL_REG (5, 16, FP);
     case 'X': REG (5, 6, VEC);
     case 'Y': REG (5, 11, VEC);
     case 'Z': REG (5, 16, VEC);
@@ -153,12 +153,12 @@ decode_mips_operand (const char *p)
     case 'o': SINT (16, 0);
     case 'p': BRANCH (16, 0, 2);
     case 'q': HINT (10, 6);
-    case 'r': REG (5, 21, GP);
+    case 'r': OPTIONAL_REG (5, 21, GP);
     case 's': REG (5, 21, GP);
     case 't': REG (5, 16, GP);
     case 'u': HINT (16, 0);
-    case 'v': REG (5, 21, GP);
-    case 'w': REG (5, 16, GP);
+    case 'v': OPTIONAL_REG (5, 21, GP);
+    case 'w': OPTIONAL_REG (5, 16, GP);
     case 'x': REG (0, 0, GP);
     case 'z': MAPPED_REG (0, 0, GP, reg_0_map);
     }
diff --git a/opcodes/mips16-opc.c b/opcodes/mips16-opc.c
index 9948741..598f823 100644
--- a/opcodes/mips16-opc.c
+++ b/opcodes/mips16-opc.c
@@ -66,8 +66,8 @@ decode_mips16_operand (char type, bfd_boolean extended_p)
     case 'i': JALX (26, 0, 2);
     case 'l': SPECIAL (6, 5, ENTRY_EXIT_LIST);
     case 'm': SPECIAL (7, 0, SAVE_RESTORE_LIST);
-    case 'v': MAPPED_REG (3, 8, GP, reg_m16_map);
-    case 'w': MAPPED_REG (3, 5, GP, reg_m16_map);
+    case 'v': OPTIONAL_MAPPED_REG (3, 8, GP, reg_m16_map);
+    case 'w': OPTIONAL_MAPPED_REG (3, 5, GP, reg_m16_map);
     case 'x': MAPPED_REG (3, 8, GP, reg_m16_map);
     case 'y': MAPPED_REG (3, 5, GP, reg_m16_map);
     case 'z': MAPPED_REG (3, 2, GP, reg_m16_map);