RISC-V/extended: Add assembler and dis-assembler hooks for extended extensions.

To keep the original functions clean, we try to provide assembler
and dis-assembler hooks as enough as possible for extended extensions.
We probably need to add more once they are not enough in the future.
However, there are several changes that might need to be discussed
as follows,

* Change the type of enums to int directly, to extend them for
extended extensions.  Not sure if the change is good enough, but
it should be the easiler way to extend enums.

* The extended operands should be parsed in the extended hooks,
validate_riscv_extended_insn and riscv_parse_extended_operands.
Obviously, we may need to reparse the opernad string in the extended
hooks, when the original functions cannot recognize them.  But the
original functions have already pointed the parsed poniter to the
next characters.  Therefore, we should use a new pointer, opargStart,
to record the position before parsing, and then pass it to the hooks
when we need to reparse the extended operands.

* Part of the "internal: unknown" errors are reported in the extended
hooks rather than the original functions.  For example, we used to
report the "internal: unreachable" in the riscv_multi_subset_supports,
to tell developers that they forgot to handle the new defined INSN_CLASS_.
And the function returns TRUE/FALSE if the instruction is allowed or not
according to the architecture string.  The riscv_extended_subset_supports
is the extended hook of riscv_multi_subset_supports, so it also returns
a bfd_boolean to check the same thing.  But it is hard to know if the
INSN_CLASS_* is unknown from the same returned bfd_boolean, unless we add
another new flag, or we just move the error report to the hook directly.
I choose the latter for now, but it may cause the code of mainline and
integration branches are inconsistent, which may affect the difficulty
of the regular merge between these two branches.

The same inconsistent problem also happens in riscv_parse_extended_operands.
The hook only parse an operand rather than all, so it just has a switch
without a for loop.  We used to set "continue" to skip the loop in the
switch, but the extended hook doesn't need the "continue".  Perhaps we
should use a single while/for in the hooks to keep the code consistent,
then the regular merge may be more easiler.

* Rename the variables to the more meaningful names in the riscv_ip,
validate_riscv_insn and print_insn_args.
- oparg: Renamed from args, means the arguments in the opcode table.
- opargStart: Added to record the start of the argument.
- asarg: Renamed from s, means the arguments of assembly string.
- asargStart: Renamed from argsStart.

* Extract the part that parsing the instruction opcode from the
riscv_disassemble_insn, since we will need to call it for many times
to search multiple opcode tables.

gas/
	* config/tc-riscv.c (enum EXTENDED_EXT_NUM): Added to choose the
	right extended opcode hashes in the riscv_find_extended_opcode_hash.
	(enum riscv_csr_class): Added CSR_CLASS_EXTENDED.
	(enum reg_class): Added RCLASS_EXTENDED_NUM.
	(enum reg_extended_class): Added to define extended registers.
	(struct riscv_csr_extra): Changed enum riscv_csr_class to int,
	to increase the expandability of enum.
	(riscv_init_csr_hash): Likewise.
	(riscv_find_opcode_hash): Handle more than one opcode hashes.
	(md_begin): Included riscv-opc-extended.h to define extended CSR.
	(init_ext_version_hash): Updated.
	(riscv_get_default_ext_version): Likewise.
	(md_assemble): Likewise.
	(s_riscv_insn): Likewsie.
	(riscv_after_parse_args): Likewise.
	(riscv_find_extended_opcode_hash): Extended hook for
	riscv_find_opcode_hash.
	(riscv_extended_subset_supports): Extended hook for
	riscv_multi_subset_supports.
	(riscv_extended_csr_class_check): Extended hook for riscv_csr_address,
	to check the CSR ISA dependency.
	(extended_macro): Extended hook for macro.
	(validate_riscv_extended_insn): Extended hook for validate_riscv_insn.
	(extended_macro_build): Extended hook for macro_build.
	(riscv_parse_extended_operands): Extended hook for riscv_ip.
	(riscv_multi_subset_supports): Updated to call extended hook.
	(riscv_csr_address): Likewise
	(macro): Likewise.
	(validate_riscv_insn): Likewise.  Also define new variables, xxx
	and xxxStart, in case single letters are not enough to represent
	all extended operands.
	(macro_build): Likewise.
	(riscv_ip): Likewise.  The asarg means assembly operand string,
	and oparg means operand string defined in the opcode table.
	* testsuite/gas/riscv/extended/extended.exp: New file to run
	extended testcases.
include/
	* opcode/riscv-opc-extended.h: New file to define encoding macros
	and CSR for extended extensions.
	* opcode/riscv.h: Included riscv-opc-extended.h.
	(enum riscv_insn_class): Added INSN_CLASS_EXTENDED.
	(struct riscv_opcode): Same as struct riscv_csr_extra.
	(enum M_EXTENDED): Added to support extended pseudo macros.
opcode/
	* riscv-dis.c (print_extended_insn_args): Extended hook for
	print_insn_args.
	(print_insn_args): Updated to call extended hook, and same as
	what validate_riscv_insn does.  Also include riscv-opc-extended.h
	to show extended CSR correctly.
	* riscv-opc.c (riscv_extended_opcodes): Added to store all
	supported extended instruction opcodes.

6 files changed, 630 insertions, 355 deletions

diff --git a/gas/config/tc-riscv.c b/gas/config/tc-riscv.c
index f7e0c929aa0..cafdda4d796 100644
--- a/gas/config/tc-riscv.c
+++ b/gas/config/tc-riscv.c
@@ -35,6 +35,12 @@
 
 #include <stdint.h>
 
+/* Used to choose the right opcode hashes for extended extensions.  */
+enum
+{
+  EXTENDED_EXT_NUM = 0
+};
+
 /* Information about an instruction, including its format, operands
    and fixups.  */
 struct riscv_cl_insn
@@ -63,7 +69,8 @@ enum riscv_csr_class
   CSR_CLASS_I,
   CSR_CLASS_I_32, /* rv32 only */
   CSR_CLASS_F, /* f-ext only */
-  CSR_CLASS_DEBUG /* debug CSR */
+  CSR_CLASS_DEBUG, /* debug CSR */
+  CSR_CLASS_EXTENDED /* Extended CSR  */
 };
 
 /* This structure holds all restricted conditions for a CSR.  */
@@ -71,7 +78,7 @@ struct riscv_csr_extra
 {
   /* Class to which this CSR belongs.  Used to decide whether or
      not this CSR is legal in the current -march context.  */
-  enum riscv_csr_class csr_class;
+  int csr_class;
 
   /* CSR may have differnet numbers in the previous priv spec.  */
   unsigned address;
@@ -247,6 +254,20 @@ riscv_subset_supports (const char *feature)
   return riscv_lookup_subset (&riscv_subsets, feature, &subset);
 }
 
+/* Check whether the extended extensions are enabled in the architecture
+   string.  */
+
+static bool
+riscv_extended_subset_supports (int insn_class)
+{
+  switch (insn_class)
+    {
+    default:
+      as_fatal ("internal: unknown INSN_CLASS (0x%x)", insn_class);
+      return false;
+    }
+}
+
 static bool
 riscv_multi_subset_supports (enum riscv_insn_class insn_class)
 {
@@ -287,8 +308,7 @@ riscv_multi_subset_supports (enum riscv_insn_class insn_class)
       return riscv_subset_supports ("zbs");
 
     default:
-      as_fatal ("internal: unreachable");
-      return false;
+      return riscv_extended_subset_supports (insn_class);
     }
 }
 
@@ -825,9 +845,15 @@ opcode_name_lookup (char **s)
   return o;
 }
 
+/* Extended registers.  */
+enum reg_extended_class
+{
+  RCLASS_EXTENDED_NUM,
+};
+
 enum reg_class
 {
-  RCLASS_GPR,
+  RCLASS_GPR = RCLASS_EXTENDED_NUM,
   RCLASS_FPR,
   RCLASS_MAX,
 
@@ -864,7 +890,7 @@ hash_reg_names (enum reg_class class, const char * const names[], unsigned n)
 static void
 riscv_init_csr_hash (const char *name,
 		     unsigned address,
-		     enum riscv_csr_class class,
+		     int class,
 		     enum riscv_spec_class define_version,
 		     enum riscv_spec_class abort_version)
 {
@@ -901,6 +927,19 @@ riscv_init_csr_hash (const char *name,
     pre_entry->next = entry;
 }
 
+/* Check the ISA dependency for extended CSR.  */
+
+static bool
+riscv_extended_csr_class_check (int csr_class)
+{
+  switch (csr_class)
+    {
+    default:
+      as_bad (_("internal: bad RISC-V CSR class (0x%x)"), csr_class);
+    }
+  return false;
+}
+
 /* Return the CSR address after checking the ISA dependency and
    the privileged spec version.
 
@@ -916,7 +955,7 @@ riscv_csr_address (const char *csr_name,
 		   struct riscv_csr_extra *entry)
 {
   struct riscv_csr_extra *saved_entry = entry;
-  enum riscv_csr_class csr_class = entry->csr_class;
+  int csr_class = entry->csr_class;
   bool need_check_version = true;
   bool result = true;
 
@@ -936,7 +975,8 @@ riscv_csr_address (const char *csr_name,
       need_check_version = false;
       break;
     default:
-      as_bad (_("internal: bad RISC-V CSR class (0x%x)"), csr_class);
+      need_check_version = false;
+      result = riscv_extended_csr_class_check (csr_class);
     }
 
   if (riscv_opts.csr_check && !result)
@@ -1049,6 +1089,28 @@ arg_lookup (char **s, const char *const *array, size_t size, unsigned *regnop)
   return false;
 }
 
+#define USE_BITS(mask,shift) (used_bits |= ((insn_t)(mask) << (shift)))
+
+/* Verify if the extended instructions are valid or not.  */
+
+static bool
+validate_riscv_extended_insn (insn_t *bits,
+			      const char **opcode_args)
+{
+  const char *oparg = *opcode_args;
+  insn_t used_bits = *bits;
+
+  switch (*oparg)
+    {
+    default:
+      return false;
+    }
+
+  *opcode_args = oparg;
+  *bits = used_bits;
+  return true;
+}
+
 /* For consistency checking, verify that all bits are specified either
    by the match/mask part of the instruction definition, or by the
    operand list. The `length` could be 0, 4 or 8, 0 for auto detection.  */
@@ -1056,8 +1118,7 @@ arg_lookup (char **s, const char *const *array, size_t size, unsigned *regnop)
 static bool
 validate_riscv_insn (const struct riscv_opcode *opc, int length)
 {
-  const char *p = opc->args;
-  char c;
+  const char *oparg, *opargStart;
   insn_t used_bits = opc->mask;
   int insn_width;
   insn_t required_bits;
@@ -1076,131 +1137,125 @@ validate_riscv_insn (const struct riscv_opcode *opc, int length)
       return false;
     }
 
-#define USE_BITS(mask,shift)	(used_bits |= ((insn_t)(mask) << (shift)))
-  while (*p)
-    switch (c = *p++)
-      {
-      case 'C': /* RVC */
-	switch (c = *p++)
-	  {
-	  case 'U': break; /* CRS1, constrained to equal RD.  */
-	  case 'c': break; /* CRS1, constrained to equal sp.  */
-	  case 'T': /* CRS2, floating point.  */
-	  case 'V': USE_BITS (OP_MASK_CRS2, OP_SH_CRS2); break;
-	  case 'S': /* CRS1S, floating point.  */
-	  case 's': USE_BITS (OP_MASK_CRS1S, OP_SH_CRS1S); break;
-	  case 'w': break; /* CRS1S, constrained to equal RD.  */
-	  case 'D': /* CRS2S, floating point.  */
-	  case 't': USE_BITS (OP_MASK_CRS2S, OP_SH_CRS2S); break;
-	  case 'x': break; /* CRS2S, constrained to equal RD.  */
-	  case 'z': break; /* CRS2S, constrained to be x0.  */
-	  case '>': /* CITYPE immediate, compressed shift.  */
-	  case 'u': /* CITYPE immediate, compressed lui.  */
-	  case 'v': /* CITYPE immediate, li to compressed lui.  */
-	  case 'o': /* CITYPE immediate, allow zero.  */
-	  case 'j': used_bits |= ENCODE_CITYPE_IMM (-1U); break;
-	  case 'L': used_bits |= ENCODE_CITYPE_ADDI16SP_IMM (-1U); break;
-	  case 'm': used_bits |= ENCODE_CITYPE_LWSP_IMM (-1U); break;
-	  case 'n': used_bits |= ENCODE_CITYPE_LDSP_IMM (-1U); break;
-	  case '6': used_bits |= ENCODE_CSSTYPE_IMM (-1U); break;
-	  case 'M': used_bits |= ENCODE_CSSTYPE_SWSP_IMM (-1U); break;
-	  case 'N': used_bits |= ENCODE_CSSTYPE_SDSP_IMM (-1U); break;
-	  case '8': used_bits |= ENCODE_CIWTYPE_IMM (-1U); break;
-	  case 'K': used_bits |= ENCODE_CIWTYPE_ADDI4SPN_IMM (-1U); break;
-	  /* CLTYPE and CSTYPE have the same immediate encoding.  */
-	  case '5': used_bits |= ENCODE_CLTYPE_IMM (-1U); break;
-	  case 'k': used_bits |= ENCODE_CLTYPE_LW_IMM (-1U); break;
-	  case 'l': used_bits |= ENCODE_CLTYPE_LD_IMM (-1U); break;
-	  case 'p': used_bits |= ENCODE_CBTYPE_IMM (-1U); break;
-	  case 'a': used_bits |= ENCODE_CJTYPE_IMM (-1U); break;
-	  case 'F': /* Compressed funct for .insn directive.  */
-	    switch (c = *p++)
-	      {
-		case '6': USE_BITS (OP_MASK_CFUNCT6, OP_SH_CFUNCT6); break;
-		case '4': USE_BITS (OP_MASK_CFUNCT4, OP_SH_CFUNCT4); break;
-		case '3': USE_BITS (OP_MASK_CFUNCT3, OP_SH_CFUNCT3); break;
-		case '2': USE_BITS (OP_MASK_CFUNCT2, OP_SH_CFUNCT2); break;
-		default:
-		  as_bad (_("internal: bad RISC-V opcode "
-			    "(unknown operand type `CF%c'): %s %s"),
-			  c, opc->name, opc->args);
-		  return false;
-	      }
-	    break;
-	  default:
-	    as_bad (_("internal: bad RISC-V opcode "
-		      "(unknown operand type `C%c'): %s %s"),
-		    c, opc->name, opc->args);
-	    return false;
-	  }
-	break;
-      case ',': break;
-      case '(': break;
-      case ')': break;
-      case '<': USE_BITS (OP_MASK_SHAMTW, OP_SH_SHAMTW); break;
-      case '>': USE_BITS (OP_MASK_SHAMT, OP_SH_SHAMT); break;
-      case 'A': break; /* Macro operand, must be symbol.  */
-      case 'B': break; /* Macro operand, must be symbol or constant.  */
-      case 'I': break; /* Macro operand, must be constant.  */
-      case 'D': /* RD, floating point.  */
-      case 'd': USE_BITS (OP_MASK_RD, OP_SH_RD); break;
-      case 'Z': /* RS1, CSR number.  */
-      case 'S': /* RS1, floating point.  */
-      case 's': USE_BITS (OP_MASK_RS1, OP_SH_RS1); break;
-      case 'U': /* RS1 and RS2 are the same, floating point.  */
-	USE_BITS (OP_MASK_RS1, OP_SH_RS1);
-	/* Fall through.  */
-      case 'T': /* RS2, floating point.  */
-      case 't': USE_BITS (OP_MASK_RS2, OP_SH_RS2); break;
-      case 'R': /* RS3, floating point.  */
-      case 'r': USE_BITS (OP_MASK_RS3, OP_SH_RS3); break;
-      case 'm': USE_BITS (OP_MASK_RM, OP_SH_RM); break;
-      case 'E': USE_BITS (OP_MASK_CSR, OP_SH_CSR); break;
-      case 'P': USE_BITS (OP_MASK_PRED, OP_SH_PRED); break;
-      case 'Q': USE_BITS (OP_MASK_SUCC, OP_SH_SUCC); break;
-      case 'o': /* ITYPE immediate, load displacement.  */
-      case 'j': used_bits |= ENCODE_ITYPE_IMM (-1U); break;
-      case 'a': used_bits |= ENCODE_JTYPE_IMM (-1U); break;
-      case 'p': used_bits |= ENCODE_BTYPE_IMM (-1U); break;
-      case 'q': used_bits |= ENCODE_STYPE_IMM (-1U); break;
-      case 'u': used_bits |= ENCODE_UTYPE_IMM (-1U); break;
-      case 'z': break; /* Zero immediate.  */
-      case '[': break; /* Unused operand.  */
-      case ']': break; /* Unused operand.  */
-      case '0': break; /* AMO displacement, must to zero.  */
-      case '1': break; /* Relaxation operand.  */
-      case 'F': /* Funct for .insn directive.  */
-	switch (c = *p++)
-	  {
-	    case '7': USE_BITS (OP_MASK_FUNCT7, OP_SH_FUNCT7); break;
-	    case '3': USE_BITS (OP_MASK_FUNCT3, OP_SH_FUNCT3); break;
-	    case '2': USE_BITS (OP_MASK_FUNCT2, OP_SH_FUNCT2); break;
-	    default:
-	      as_bad (_("internal: bad RISC-V opcode "
-			"(unknown operand type `F%c'): %s %s"),
-		      c, opc->name, opc->args);
-	    return false;
-	  }
-	break;
-      case 'O': /* Opcode for .insn directive.  */
-	switch (c = *p++)
-	  {
-	    case '4': USE_BITS (OP_MASK_OP, OP_SH_OP); break;
-	    case '2': USE_BITS (OP_MASK_OP2, OP_SH_OP2); break;
+  for (oparg = opc->args; *oparg; ++oparg)
+    {
+      opargStart = oparg;
+      switch (*oparg)
+	{
+	case 'C': /* RVC */
+	  switch (*++oparg)
+	    {
+	    case 'U': break; /* CRS1, constrained to equal RD.  */
+	    case 'c': break; /* CRS1, constrained to equal sp.  */
+	    case 'T': /* CRS2, floating point.  */
+	    case 'V': USE_BITS (OP_MASK_CRS2, OP_SH_CRS2); break;
+	    case 'S': /* CRS1S, floating point.  */
+	    case 's': USE_BITS (OP_MASK_CRS1S, OP_SH_CRS1S); break;
+	    case 'w': break; /* CRS1S, constrained to equal RD.  */
+	    case 'D': /* CRS2S, floating point.  */
+	    case 't': USE_BITS (OP_MASK_CRS2S, OP_SH_CRS2S); break;
+	    case 'x': break; /* CRS2S, constrained to equal RD.  */
+	    case 'z': break; /* CRS2S, constrained to be x0.  */
+	    case '>': /* CITYPE immediate, compressed shift.  */
+	    case 'u': /* CITYPE immediate, compressed lui.  */
+	    case 'v': /* CITYPE immediate, li to compressed lui.  */
+	    case 'o': /* CITYPE immediate, allow zero.  */
+	    case 'j': used_bits |= ENCODE_CITYPE_IMM (-1U); break;
+	    case 'L': used_bits |= ENCODE_CITYPE_ADDI16SP_IMM (-1U); break;
+	    case 'm': used_bits |= ENCODE_CITYPE_LWSP_IMM (-1U); break;
+	    case 'n': used_bits |= ENCODE_CITYPE_LDSP_IMM (-1U); break;
+	    case '6': used_bits |= ENCODE_CSSTYPE_IMM (-1U); break;
+	    case 'M': used_bits |= ENCODE_CSSTYPE_SWSP_IMM (-1U); break;
+	    case 'N': used_bits |= ENCODE_CSSTYPE_SDSP_IMM (-1U); break;
+	    case '8': used_bits |= ENCODE_CIWTYPE_IMM (-1U); break;
+	    case 'K': used_bits |= ENCODE_CIWTYPE_ADDI4SPN_IMM (-1U); break;
+	    /* CLTYPE and CSTYPE have the same immediate encoding.  */
+	    case '5': used_bits |= ENCODE_CLTYPE_IMM (-1U); break;
+	    case 'k': used_bits |= ENCODE_CLTYPE_LW_IMM (-1U); break;
+	    case 'l': used_bits |= ENCODE_CLTYPE_LD_IMM (-1U); break;
+	    case 'p': used_bits |= ENCODE_CBTYPE_IMM (-1U); break;
+	    case 'a': used_bits |= ENCODE_CJTYPE_IMM (-1U); break;
+	    case 'F': /* Compressed funct for .insn directive.  */
+	      switch (*++oparg)
+		{
+		  case '6': USE_BITS (OP_MASK_CFUNCT6, OP_SH_CFUNCT6); break;
+		  case '4': USE_BITS (OP_MASK_CFUNCT4, OP_SH_CFUNCT4); break;
+		  case '3': USE_BITS (OP_MASK_CFUNCT3, OP_SH_CFUNCT3); break;
+		  case '2': USE_BITS (OP_MASK_CFUNCT2, OP_SH_CFUNCT2); break;
+		  default:
+		    goto validate_extended_insn;
+		}
+	      break;
 	    default:
+	      goto validate_extended_insn;
+	    }
+	  break;
+	case ',': break;
+	case '(': break;
+	case ')': break;
+	case '<': USE_BITS (OP_MASK_SHAMTW, OP_SH_SHAMTW); break;
+	case '>': USE_BITS (OP_MASK_SHAMT, OP_SH_SHAMT); break;
+	case 'A': break; /* Macro operand, must be symbol.  */
+	case 'B': break; /* Macro operand, must be symbol or constant.  */
+	case 'I': break; /* Macro operand, must be constant.  */
+	case 'D': /* RD, floating point.  */
+	case 'd': USE_BITS (OP_MASK_RD, OP_SH_RD); break;
+	case 'Z': /* RS1, CSR number.  */
+	case 'S': /* RS1, floating point.  */
+	case 's': USE_BITS (OP_MASK_RS1, OP_SH_RS1); break;
+	case 'U': /* RS1 and RS2 are the same, floating point.  */
+	  USE_BITS (OP_MASK_RS1, OP_SH_RS1);
+	  /* Fall through.  */
+	case 'T': /* RS2, floating point.  */
+	case 't': USE_BITS (OP_MASK_RS2, OP_SH_RS2); break;
+	case 'R': /* RS3, floating point.  */
+	case 'r': USE_BITS (OP_MASK_RS3, OP_SH_RS3); break;
+	case 'm': USE_BITS (OP_MASK_RM, OP_SH_RM); break;
+	case 'E': USE_BITS (OP_MASK_CSR, OP_SH_CSR); break;
+	case 'P': USE_BITS (OP_MASK_PRED, OP_SH_PRED); break;
+	case 'Q': USE_BITS (OP_MASK_SUCC, OP_SH_SUCC); break;
+	case 'o': /* ITYPE immediate, load displacement.  */
+	case 'j': used_bits |= ENCODE_ITYPE_IMM (-1U); break;
+	case 'a': used_bits |= ENCODE_JTYPE_IMM (-1U); break;
+	case 'p': used_bits |= ENCODE_BTYPE_IMM (-1U); break;
+	case 'q': used_bits |= ENCODE_STYPE_IMM (-1U); break;
+	case 'u': used_bits |= ENCODE_UTYPE_IMM (-1U); break;
+	case 'z': break; /* Zero immediate.  */
+	case '[': break; /* Unused operand.  */
+	case ']': break; /* Unused operand.  */
+	case '0': break; /* AMO displacement, must to zero.  */
+	case '1': break; /* Relaxation operand.  */
+	case 'F': /* Funct for .insn directive.  */
+	  switch (*++oparg)
+	    {
+	      case '7': USE_BITS (OP_MASK_FUNCT7, OP_SH_FUNCT7); break;
+	      case '3': USE_BITS (OP_MASK_FUNCT3, OP_SH_FUNCT3); break;
+	      case '2': USE_BITS (OP_MASK_FUNCT2, OP_SH_FUNCT2); break;
+	      default:
+		goto validate_extended_insn;
+	    }
+	  break;
+	case 'O': /* Opcode for .insn directive.  */
+	  switch (*++oparg)
+	    {
+	      case '4': USE_BITS (OP_MASK_OP, OP_SH_OP); break;
+	      case '2': USE_BITS (OP_MASK_OP2, OP_SH_OP2); break;
+	      default:
+		goto validate_extended_insn;
+	    }
+	  break;
+	default:
+	validate_extended_insn:
+	  oparg = opargStart;
+	  if (!validate_riscv_extended_insn (&used_bits, &oparg))
+	    {
 	      as_bad (_("internal: bad RISC-V opcode "
-			"(unknown operand type `F%c'): %s %s"),
-		      c, opc->name, opc->args);
-	     return false;
-	  }
-	break;
-      default:
-	as_bad (_("internal: bad RISC-V opcode "
-		  "(unknown operand type `%c'): %s %s"),
-		c, opc->name, opc->args);
-	return false;
-      }
-#undef USE_BITS
+			"(unknown operand type `%s'): %s %s"),
+		      opargStart, opc->name, opc->args);
+	      return false;
+	    }
+	}
+    }
   if (used_bits != required_bits)
     {
       as_bad (_("internal: bad RISC-V opcode "
@@ -1212,6 +1267,8 @@ validate_riscv_insn (const struct riscv_opcode *opc, int length)
   return true;
 }
 
+#undef USE_BITS
+
 struct percent_op_match
 {
   const char *str;
@@ -1285,6 +1342,7 @@ md_begin (void)
 #define DECLARE_CSR_ALIAS(name, num, class, define_version, abort_version) \
   DECLARE_CSR(name, num, class, define_version, abort_version);
 #include "opcode/riscv-opc.h"
+#include "opcode/riscv-opc-extended.h"
 #undef DECLARE_CSR
 
   opcode_names_hash = str_htab_create ();
@@ -1382,6 +1440,65 @@ append_insn (struct riscv_cl_insn *ip, expressionS *address_expr,
     }
 }
 
+/* Find the extended extensions from the specific opcode hashes.  */
+
+static struct riscv_opcode *
+riscv_find_extended_opcode_hash (char *str ATTRIBUTE_UNUSED)
+{
+  struct riscv_opcode *insn = NULL;
+  unsigned int i = 0;
+
+  while (riscv_extended_opcodes[i] != NULL)
+    {
+      if (insn != NULL)
+        break;
+
+      switch (i)
+	{
+	default:
+	  break;
+	}
+      i++;
+    }
+
+  return insn;
+}
+
+/* Find instruction opcode from the opcode hashes.  */
+
+static struct riscv_opcode *
+riscv_find_opcode_hash (char *str, htab_t hash)
+{
+  struct riscv_opcode *insn;
+
+  insn = (struct riscv_opcode *) str_hash_find (hash, str);
+  if (insn == NULL)
+    insn = riscv_find_extended_opcode_hash (str);
+
+  return insn;
+}
+
+/* Macro expansion for extended pseudo instruction.  */
+
+static bool
+extended_macro_build (struct riscv_cl_insn* insn_p,
+		      const char **fmt_p,
+		      va_list args ATTRIBUTE_UNUSED)
+{
+  struct riscv_cl_insn insn = *insn_p;
+  const char *fmt = *fmt_p;
+
+  switch (*fmt)
+    {
+    default:
+      return false;
+    }
+
+  *insn_p = insn;
+  *fmt_p = fmt;
+  return true;
+}
+
 /* Build an instruction created by a macro expansion.  This is passed
    a pointer to the count of instructions created so far, an expression,
    the name of the instruction to build, an operand format string, and
@@ -1394,11 +1511,12 @@ macro_build (expressionS *ep, const char *name, const char *fmt, ...)
   struct riscv_cl_insn insn;
   bfd_reloc_code_real_type r;
   va_list args;
+  const char *fmtStart;
 
   va_start (args, fmt);
 
   r = BFD_RELOC_UNUSED;
-  mo = (struct riscv_opcode *) str_hash_find (op_hash, name);
+  mo = riscv_find_opcode_hash ((char *) name, op_hash);
   gas_assert (mo);
 
   /* Find a non-RVC variant of the instruction.  append_insn will compress
@@ -1408,9 +1526,10 @@ macro_build (expressionS *ep, const char *name, const char *fmt, ...)
   gas_assert (strcmp (name, mo->name) == 0);
 
   create_insn (&insn, mo);
-  for (;;)
+  for (;; ++fmt)
     {
-      switch (*fmt++)
+      fmtStart = fmt;
+      switch (*fmt)
 	{
 	case 'd':
 	  INSERT_OPERAND (RD, insn, va_arg (args, int));
@@ -1436,7 +1555,10 @@ macro_build (expressionS *ep, const char *name, const char *fmt, ...)
 	case ',':
 	  continue;
 	default:
-	  as_fatal (_("internal: invalid macro"));
+	  fmt = fmtStart;
+	  if (extended_macro_build (&insn, &fmt, args))
+	    continue;
+	  as_fatal (_("internal: invalid macro argument `%s'"), fmtStart);
 	}
       break;
     }
@@ -1624,6 +1746,22 @@ riscv_ext (int destreg, int srcreg, unsigned shift, bool sign)
     }
 }
 
+/* Expand RISC-V extended assembly macros into one or more instructions.  */
+
+static bool
+extended_macro (struct riscv_cl_insn *ip ATTRIBUTE_UNUSED,
+		int mask,
+		expressionS *imm_expr ATTRIBUTE_UNUSED,
+		bfd_reloc_code_real_type *imm_reloc ATTRIBUTE_UNUSED)
+{
+  switch (mask)
+    {
+    default:
+      return false;
+    }
+  return true;
+}
+
 /* Expand RISC-V assembly macros into one or more instructions.  */
 
 static void
@@ -1763,7 +1901,8 @@ macro (struct riscv_cl_insn *ip, expressionS *imm_expr,
       break;
 
     default:
-      as_bad (_("internal: macro %s not implemented"), ip->insn_mo->name);
+      if (!extended_macro (ip, mask, imm_expr, imm_reloc))
+	as_bad (_("internal: macro %s not implemented"), ip->insn_mo->name);
       break;
     }
 }
@@ -1934,7 +2073,7 @@ my_getOpcodeExpression (expressionS *ep, bfd_reloc_code_real_type *reloc,
 }
 
 /* Detect and handle implicitly zero load-store offsets.  For example,
-   "lw t0, (t1)" is shorthand for "lw t0, 0(t1)".  Return TRUE iff such
+   "lw t0, (t1)" is shorthand for "lw t0, 0(t1)".  Return true iff such
    an implicit offset was detected.  */
 
 static bool
@@ -2001,7 +2140,7 @@ riscv_csr_read_only_check (insn_t insn)
   return true;
 }
 
-/* Return True if it is a privileged instruction.  Otherwise, return FALSE.
+/* Return True if it is a privileged instruction.  Otherwise, return false.
 
    uret is actually a N-ext instruction.  So it is better to regard it as
    an user instruction rather than the priv instruction.
@@ -2026,6 +2165,31 @@ riscv_is_priv_insn (insn_t insn)
 	  || ((insn ^ MATCH_SFENCE_VM) & MASK_SFENCE_VM) == 0);
 }
 
+/* Parse all extended operands for riscv_ip.  */
+
+static bool
+riscv_parse_extended_operands (struct riscv_cl_insn *ip ATTRIBUTE_UNUSED,
+			       expressionS *imm_expr ATTRIBUTE_UNUSED,
+			       bfd_reloc_code_real_type *imm_reloc ATTRIBUTE_UNUSED,
+			       const char **opcode_args,
+			       char **assembly_args)
+{
+  const char *oparg = *opcode_args;
+  char *asarg = *assembly_args;
+
+  switch (*oparg)
+    {
+    default:
+      as_fatal (_("internal: unknown argument type `%s'"),
+		*opcode_args);
+      return false;
+    }
+
+  *opcode_args = oparg;
+  *assembly_args = asarg;
+  return true;
+}
+
 /* This routine assembles an instruction into its binary format.  As a
    side effect, it sets the global variable imm_reloc to the type of
    relocation to do if one of the operands is an address expression.  */
@@ -2034,13 +2198,11 @@ static const char *
 riscv_ip (char *str, struct riscv_cl_insn *ip, expressionS *imm_expr,
 	  bfd_reloc_code_real_type *imm_reloc, htab_t hash)
 {
-  char *s;
-  const char *args;
-  char c = 0;
+  const char *oparg, *opargStart;
+  char *asarg, *asargStart;
+  char save_c = 0;
   struct riscv_opcode *insn;
-  char *argsStart;
   unsigned int regno;
-  char save_c = 0;
   int argnum;
   const struct percent_op_match *p;
   const char *error = "unrecognized opcode";
@@ -2049,17 +2211,17 @@ riscv_ip (char *str, struct riscv_cl_insn *ip, expressionS *imm_expr,
 
   /* Parse the name of the instruction.  Terminate the string if whitespace
      is found so that str_hash_find only sees the name part of the string.  */
-  for (s = str; *s != '\0'; ++s)
-    if (ISSPACE (*s))
+  for (asarg = str; *asarg!= '\0'; ++asarg)
+    if (ISSPACE (*asarg))
       {
-	save_c = *s;
-	*s++ = '\0';
+	save_c = *asarg;
+	*asarg++ = '\0';
 	break;
       }
 
-  insn = (struct riscv_opcode *) str_hash_find (hash, str);
+  insn = riscv_find_opcode_hash (str, hash);
 
-  argsStart = s;
+  asargStart = asarg;
   for ( ; insn && insn->name && strcmp (insn->name, str) == 0; insn++)
     {
       if ((insn->xlen_requirement != 0) && (xlen != insn->xlen_requirement))
@@ -2075,10 +2237,11 @@ riscv_ip (char *str, struct riscv_cl_insn *ip, expressionS *imm_expr,
       *imm_reloc = BFD_RELOC_UNUSED;
       p = percent_op_itype;
 
-      for (args = insn->args;; ++args)
+      for (oparg = insn->args;; ++oparg)
 	{
-	  s += strspn (s, " \t");
-	  switch (*args)
+	  opargStart = oparg;
+	  asarg += strspn (asarg, " \t");
+	  switch (*oparg)
 	    {
 	    case '\0': /* End of args.  */
 	      if (insn->pinfo != INSN_MACRO)
@@ -2105,12 +2268,12 @@ riscv_ip (char *str, struct riscv_cl_insn *ip, expressionS *imm_expr,
 		      /* Restore the character in advance, since we want to
 			 report the detailed warning message here.  */
 		      if (save_c)
-			*(argsStart - 1) = save_c;
+			*(asargStart - 1) = save_c;
 		      as_warn (_("read-only CSR is written `%s'"), str);
 		      insn_with_csr = false;
 		    }
 		}
-	      if (*s != '\0')
+	      if (*asarg != '\0')
 		break;
 	      /* Successful assembly.  */
 	      error = NULL;
@@ -2118,62 +2281,62 @@ riscv_ip (char *str, struct riscv_cl_insn *ip, expressionS *imm_expr,
 	      goto out;
 
 	    case 'C': /* RVC */
-	      switch (*++args)
+	      switch (*++oparg)
 		{
 		case 's': /* RS1 x8-x15.  */
-		  if (!reg_lookup (&s, RCLASS_GPR, &regno)
+		  if (!reg_lookup (&asarg, RCLASS_GPR, &regno)
 		      || !(regno >= 8 && regno <= 15))
 		    break;
 		  INSERT_OPERAND (CRS1S, *ip, regno % 8);
 		  continue;
 		case 'w': /* RS1 x8-x15, constrained to equal RD x8-x15.  */
-		  if (!reg_lookup (&s, RCLASS_GPR, &regno)
+		  if (!reg_lookup (&asarg, RCLASS_GPR, &regno)
 		      || EXTRACT_OPERAND (CRS1S, ip->insn_opcode) + 8 != regno)
 		    break;
 		  continue;
 		case 't': /* RS2 x8-x15.  */
-		  if (!reg_lookup (&s, RCLASS_GPR, &regno)
+		  if (!reg_lookup (&asarg, RCLASS_GPR, &regno)
 		      || !(regno >= 8 && regno <= 15))
 		    break;
 		  INSERT_OPERAND (CRS2S, *ip, regno % 8);
 		  continue;
 		case 'x': /* RS2 x8-x15, constrained to equal RD x8-x15.  */
-		  if (!reg_lookup (&s, RCLASS_GPR, &regno)
+		  if (!reg_lookup (&asarg, RCLASS_GPR, &regno)
 		      || EXTRACT_OPERAND (CRS2S, ip->insn_opcode) + 8 != regno)
 		    break;
 		  continue;
 		case 'U': /* RS1, constrained to equal RD.  */
-		  if (!reg_lookup (&s, RCLASS_GPR, &regno)
+		  if (!reg_lookup (&asarg, RCLASS_GPR, &regno)
 		      || EXTRACT_OPERAND (RD, ip->insn_opcode) != regno)
 		    break;
 		  continue;
 		case 'V': /* RS2 */
-		  if (!reg_lookup (&s, RCLASS_GPR, &regno))
+		  if (!reg_lookup (&asarg, RCLASS_GPR, &regno))
 		    break;
 		  INSERT_OPERAND (CRS2, *ip, regno);
 		  continue;
 		case 'c': /* RS1, constrained to equal sp.  */
-		  if (!reg_lookup (&s, RCLASS_GPR, &regno)
+		  if (!reg_lookup (&asarg, RCLASS_GPR, &regno)
 		      || regno != X_SP)
 		    break;
 		  continue;
 		case 'z': /* RS2, constrained to equal x0.  */
-		  if (!reg_lookup (&s, RCLASS_GPR, &regno)
+		  if (!reg_lookup (&asarg, RCLASS_GPR, &regno)
 		      || regno != 0)
 		    break;
 		  continue;
 		case '>': /* Shift amount, 0 - (XLEN-1).  */
-		  if (my_getSmallExpression (imm_expr, imm_reloc, s, p)
+		  if (my_getSmallExpression (imm_expr, imm_reloc, asarg, p)
 		      || imm_expr->X_op != O_constant
 		      || (unsigned long) imm_expr->X_add_number >= xlen)
 		    break;
 		  ip->insn_opcode |= ENCODE_CITYPE_IMM (imm_expr->X_add_number);
 		rvc_imm_done:
-		  s = expr_end;
+		  asarg = expr_end;
 		  imm_expr->X_op = O_absent;
 		  continue;
 		case '5':
-		  if (my_getSmallExpression (imm_expr, imm_reloc, s, p)
+		  if (my_getSmallExpression (imm_expr, imm_reloc, asarg, p)
 		      || imm_expr->X_op != O_constant
 		      || imm_expr->X_add_number < 0
 		      || imm_expr->X_add_number >= 32
@@ -2182,7 +2345,7 @@ riscv_ip (char *str, struct riscv_cl_insn *ip, expressionS *imm_expr,
 		  ip->insn_opcode |= ENCODE_CLTYPE_IMM (imm_expr->X_add_number);
 		  goto rvc_imm_done;
 		case '6':
-		  if (my_getSmallExpression (imm_expr, imm_reloc, s, p)
+		  if (my_getSmallExpression (imm_expr, imm_reloc, asarg, p)
 		      || imm_expr->X_op != O_constant
 		      || imm_expr->X_add_number < 0
 		      || imm_expr->X_add_number >= 64
@@ -2191,7 +2354,7 @@ riscv_ip (char *str, struct riscv_cl_insn *ip, expressionS *imm_expr,
 		  ip->insn_opcode |= ENCODE_CSSTYPE_IMM (imm_expr->X_add_number);
 		  goto rvc_imm_done;
 		case '8':
-		  if (my_getSmallExpression (imm_expr, imm_reloc, s, p)
+		  if (my_getSmallExpression (imm_expr, imm_reloc, asarg, p)
 		      || imm_expr->X_op != O_constant
 		      || imm_expr->X_add_number < 0
 		      || imm_expr->X_add_number >= 256
@@ -2200,7 +2363,7 @@ riscv_ip (char *str, struct riscv_cl_insn *ip, expressionS *imm_expr,
 		  ip->insn_opcode |= ENCODE_CIWTYPE_IMM (imm_expr->X_add_number);
 		  goto rvc_imm_done;
 		case 'j':
-		  if (my_getSmallExpression (imm_expr, imm_reloc, s, p)
+		  if (my_getSmallExpression (imm_expr, imm_reloc, asarg, p)
 		      || imm_expr->X_op != O_constant
 		      || imm_expr->X_add_number == 0
 		      || !VALID_CITYPE_IMM ((valueT) imm_expr->X_add_number))
@@ -2208,27 +2371,27 @@ riscv_ip (char *str, struct riscv_cl_insn *ip, expressionS *imm_expr,
 		  ip->insn_opcode |= ENCODE_CITYPE_IMM (imm_expr->X_add_number);
 		  goto rvc_imm_done;
 		case 'k':
-		  if (riscv_handle_implicit_zero_offset (imm_expr, s))
+		  if (riscv_handle_implicit_zero_offset (imm_expr, asarg))
 		    continue;
-		  if (my_getSmallExpression (imm_expr, imm_reloc, s, p)
+		  if (my_getSmallExpression (imm_expr, imm_reloc, asarg, p)
 		      || imm_expr->X_op != O_constant
 		      || !VALID_CLTYPE_LW_IMM ((valueT) imm_expr->X_add_number))
 		    break;
 		  ip->insn_opcode |= ENCODE_CLTYPE_LW_IMM (imm_expr->X_add_number);
 		  goto rvc_imm_done;
 		case 'l':
-		  if (riscv_handle_implicit_zero_offset (imm_expr, s))
+		  if (riscv_handle_implicit_zero_offset (imm_expr, asarg))
 		    continue;
-		  if (my_getSmallExpression (imm_expr, imm_reloc, s, p)
+		  if (my_getSmallExpression (imm_expr, imm_reloc, asarg, p)
 		      || imm_expr->X_op != O_constant
 		      || !VALID_CLTYPE_LD_IMM ((valueT) imm_expr->X_add_number))
 		    break;
 		  ip->insn_opcode |= ENCODE_CLTYPE_LD_IMM (imm_expr->X_add_number);
 		  goto rvc_imm_done;
 		case 'm':
-		  if (riscv_handle_implicit_zero_offset (imm_expr, s))
+		  if (riscv_handle_implicit_zero_offset (imm_expr, asarg))
 		    continue;
-		  if (my_getSmallExpression (imm_expr, imm_reloc, s, p)
+		  if (my_getSmallExpression (imm_expr, imm_reloc, asarg, p)
 		      || imm_expr->X_op != O_constant
 		      || !VALID_CITYPE_LWSP_IMM ((valueT) imm_expr->X_add_number))
 		    break;
@@ -2236,9 +2399,9 @@ riscv_ip (char *str, struct riscv_cl_insn *ip, expressionS *imm_expr,
 		    ENCODE_CITYPE_LWSP_IMM (imm_expr->X_add_number);
 		  goto rvc_imm_done;
 		case 'n':
-		  if (riscv_handle_implicit_zero_offset (imm_expr, s))
+		  if (riscv_handle_implicit_zero_offset (imm_expr, asarg))
 		    continue;
-		  if (my_getSmallExpression (imm_expr, imm_reloc, s, p)
+		  if (my_getSmallExpression (imm_expr, imm_reloc, asarg, p)
 		      || imm_expr->X_op != O_constant
 		      || !VALID_CITYPE_LDSP_IMM ((valueT) imm_expr->X_add_number))
 		    break;
@@ -2246,7 +2409,7 @@ riscv_ip (char *str, struct riscv_cl_insn *ip, expressionS *imm_expr,
 		    ENCODE_CITYPE_LDSP_IMM (imm_expr->X_add_number);
 		  goto rvc_imm_done;
 		case 'o':
-		  if (my_getSmallExpression (imm_expr, imm_reloc, s, p)
+		  if (my_getSmallExpression (imm_expr, imm_reloc, asarg, p)
 		      || imm_expr->X_op != O_constant
 		      /* C.addiw, c.li, and c.andi allow zero immediate.
 			 C.addi allows zero immediate as hint.  Otherwise this
@@ -2256,7 +2419,7 @@ riscv_ip (char *str, struct riscv_cl_insn *ip, expressionS *imm_expr,
 		  ip->insn_opcode |= ENCODE_CITYPE_IMM (imm_expr->X_add_number);
 		  goto rvc_imm_done;
 		case 'K':
-		  if (my_getSmallExpression (imm_expr, imm_reloc, s, p)
+		  if (my_getSmallExpression (imm_expr, imm_reloc, asarg, p)
 		      || imm_expr->X_op != O_constant
 		      || imm_expr->X_add_number == 0
 		      || !VALID_CIWTYPE_ADDI4SPN_IMM ((valueT) imm_expr->X_add_number))
@@ -2265,7 +2428,7 @@ riscv_ip (char *str, struct riscv_cl_insn *ip, expressionS *imm_expr,
 		    ENCODE_CIWTYPE_ADDI4SPN_IMM (imm_expr->X_add_number);
 		  goto rvc_imm_done;
 		case 'L':
-		  if (my_getSmallExpression (imm_expr, imm_reloc, s, p)
+		  if (my_getSmallExpression (imm_expr, imm_reloc, asarg, p)
 		      || imm_expr->X_op != O_constant
 		      || !VALID_CITYPE_ADDI16SP_IMM ((valueT) imm_expr->X_add_number))
 		    break;
@@ -2273,9 +2436,9 @@ riscv_ip (char *str, struct riscv_cl_insn *ip, expressionS *imm_expr,
 		    ENCODE_CITYPE_ADDI16SP_IMM (imm_expr->X_add_number);
 		  goto rvc_imm_done;
 		case 'M':
-		  if (riscv_handle_implicit_zero_offset (imm_expr, s))
+		  if (riscv_handle_implicit_zero_offset (imm_expr, asarg))
 		    continue;
-		  if (my_getSmallExpression (imm_expr, imm_reloc, s, p)
+		  if (my_getSmallExpression (imm_expr, imm_reloc, asarg, p)
 		      || imm_expr->X_op != O_constant
 		      || !VALID_CSSTYPE_SWSP_IMM ((valueT) imm_expr->X_add_number))
 		    break;
@@ -2283,9 +2446,9 @@ riscv_ip (char *str, struct riscv_cl_insn *ip, expressionS *imm_expr,
 		    ENCODE_CSSTYPE_SWSP_IMM (imm_expr->X_add_number);
 		  goto rvc_imm_done;
 		case 'N':
-		  if (riscv_handle_implicit_zero_offset (imm_expr, s))
+		  if (riscv_handle_implicit_zero_offset (imm_expr, asarg))
 		    continue;
-		  if (my_getSmallExpression (imm_expr, imm_reloc, s, p)
+		  if (my_getSmallExpression (imm_expr, imm_reloc, asarg, p)
 		      || imm_expr->X_op != O_constant
 		      || !VALID_CSSTYPE_SDSP_IMM ((valueT) imm_expr->X_add_number))
 		    break;
@@ -2294,7 +2457,7 @@ riscv_ip (char *str, struct riscv_cl_insn *ip, expressionS *imm_expr,
 		  goto rvc_imm_done;
 		case 'u':
 		  p = percent_op_utype;
-		  if (my_getSmallExpression (imm_expr, imm_reloc, s, p))
+		  if (my_getSmallExpression (imm_expr, imm_reloc, asarg, p))
 		    break;
 		rvc_lui:
 		  if (imm_expr->X_op != O_constant
@@ -2307,7 +2470,7 @@ riscv_ip (char *str, struct riscv_cl_insn *ip, expressionS *imm_expr,
 		  ip->insn_opcode |= ENCODE_CITYPE_IMM (imm_expr->X_add_number);
 		  goto rvc_imm_done;
 		case 'v':
-		  if (my_getSmallExpression (imm_expr, imm_reloc, s, p)
+		  if (my_getSmallExpression (imm_expr, imm_reloc, asarg, p)
 		      || (imm_expr->X_add_number & (RISCV_IMM_REACH - 1))
 		      || ((int32_t)imm_expr->X_add_number
 			  != imm_expr->X_add_number))
@@ -2320,27 +2483,27 @@ riscv_ip (char *str, struct riscv_cl_insn *ip, expressionS *imm_expr,
 		case 'a':
 		  goto jump;
 		case 'S': /* Floating-point RS1 x8-x15.  */
-		  if (!reg_lookup (&s, RCLASS_FPR, &regno)
+		  if (!reg_lookup (&asarg, RCLASS_FPR, &regno)
 		      || !(regno >= 8 && regno <= 15))
 		    break;
 		  INSERT_OPERAND (CRS1S, *ip, regno % 8);
 		  continue;
 		case 'D': /* Floating-point RS2 x8-x15.  */
-		  if (!reg_lookup (&s, RCLASS_FPR, &regno)
+		  if (!reg_lookup (&asarg, RCLASS_FPR, &regno)
 		      || !(regno >= 8 && regno <= 15))
 		    break;
 		  INSERT_OPERAND (CRS2S, *ip, regno % 8);
 		  continue;
 		case 'T': /* Floating-point RS2.  */
-		  if (!reg_lookup (&s, RCLASS_FPR, &regno))
+		  if (!reg_lookup (&asarg, RCLASS_FPR, &regno))
 		    break;
 		  INSERT_OPERAND (CRS2, *ip, regno);
 		  continue;
 		case 'F':
-		  switch (*++args)
+		  switch (*++oparg)
 		    {
 		      case '6':
-		        if (my_getSmallExpression (imm_expr, imm_reloc, s, p)
+		        if (my_getSmallExpression (imm_expr, imm_reloc, asarg, p)
 			    || imm_expr->X_op != O_constant
 			    || imm_expr->X_add_number < 0
 			    || imm_expr->X_add_number >= 64)
@@ -2351,11 +2514,11 @@ riscv_ip (char *str, struct riscv_cl_insn *ip, expressionS *imm_expr,
 			  }
 			INSERT_OPERAND (CFUNCT6, *ip, imm_expr->X_add_number);
 			imm_expr->X_op = O_absent;
-			s = expr_end;
+			asarg = expr_end;
 			continue;
 
 		      case '4':
-		        if (my_getSmallExpression (imm_expr, imm_reloc, s, p)
+		        if (my_getSmallExpression (imm_expr, imm_reloc, asarg, p)
 			    || imm_expr->X_op != O_constant
 			    || imm_expr->X_add_number < 0
 			    || imm_expr->X_add_number >= 16)
@@ -2366,11 +2529,11 @@ riscv_ip (char *str, struct riscv_cl_insn *ip, expressionS *imm_expr,
 			  }
 			INSERT_OPERAND (CFUNCT4, *ip, imm_expr->X_add_number);
 			imm_expr->X_op = O_absent;
-			s = expr_end;
+			asarg = expr_end;
 			continue;
 
 		      case '3':
-			if (my_getSmallExpression (imm_expr, imm_reloc, s, p)
+			if (my_getSmallExpression (imm_expr, imm_reloc, asarg, p)
 			    || imm_expr->X_op != O_constant
 			    || imm_expr->X_add_number < 0
 			    || imm_expr->X_add_number >= 8)
@@ -2381,11 +2544,11 @@ riscv_ip (char *str, struct riscv_cl_insn *ip, expressionS *imm_expr,
 			  }
 			INSERT_OPERAND (CFUNCT3, *ip, imm_expr->X_add_number);
 			imm_expr->X_op = O_absent;
-			s = expr_end;
+			asarg = expr_end;
 			continue;
 
 		      case '2':
-			if (my_getSmallExpression (imm_expr, imm_reloc, s, p)
+			if (my_getSmallExpression (imm_expr, imm_reloc, asarg, p)
 			    || imm_expr->X_op != O_constant
 			    || imm_expr->X_add_number < 0
 			    || imm_expr->X_add_number >= 4)
@@ -2396,89 +2559,88 @@ riscv_ip (char *str, struct riscv_cl_insn *ip, expressionS *imm_expr,
 			  }
 			INSERT_OPERAND (CFUNCT2, *ip, imm_expr->X_add_number);
 			imm_expr->X_op = O_absent;
-			s = expr_end;
+			asarg = expr_end;
 			continue;
 
 		      default:
-			as_bad (_("internal: unknown compressed funct "
-				  "field specifier `CF%c'"), *args);
+			goto parse_extended_operand;
 		    }
 		  break;
 
 		default:
-		  as_bad (_("internal: unknown compressed field "
-			    "specifier `C%c'"), *args);
+		  goto parse_extended_operand;
 		}
 	      break;
 
 	    case ',':
 	      ++argnum;
-	      if (*s++ == *args)
+	      if (*asarg++ == *oparg)
 		continue;
-	      s--;
+	      asarg--;
 	      break;
 
 	    case '(':
 	    case ')':
 	    case '[':
 	    case ']':
-	      if (*s++ == *args)
+	      if (*asarg++ == *oparg)
 		continue;
 	      break;
 
 	    case '<': /* Shift amount, 0 - 31.  */
-	      my_getExpression (imm_expr, s);
+	      my_getExpression (imm_expr, asarg);
 	      check_absolute_expr (ip, imm_expr, false);
 	      if ((unsigned long) imm_expr->X_add_number > 31)
 		as_bad (_("improper shift amount (%lu)"),
 			(unsigned long) imm_expr->X_add_number);
 	      INSERT_OPERAND (SHAMTW, *ip, imm_expr->X_add_number);
 	      imm_expr->X_op = O_absent;
-	      s = expr_end;
+	      asarg = expr_end;
 	      continue;
 
 	    case '>': /* Shift amount, 0 - (XLEN-1).  */
-	      my_getExpression (imm_expr, s);
+	      my_getExpression (imm_expr, asarg);
 	      check_absolute_expr (ip, imm_expr, false);
 	      if ((unsigned long) imm_expr->X_add_number >= xlen)
 		as_bad (_("improper shift amount (%lu)"),
 			(unsigned long) imm_expr->X_add_number);
 	      INSERT_OPERAND (SHAMT, *ip, imm_expr->X_add_number);
 	      imm_expr->X_op = O_absent;
-	      s = expr_end;
+	      asarg = expr_end;
 	      continue;
 
 	    case 'Z': /* CSRRxI immediate.  */
-	      my_getExpression (imm_expr, s);
+	      my_getExpression (imm_expr, asarg);
 	      check_absolute_expr (ip, imm_expr, false);
 	      if ((unsigned long) imm_expr->X_add_number > 31)
 		as_bad (_("improper CSRxI immediate (%lu)"),
 			(unsigned long) imm_expr->X_add_number);
 	      INSERT_OPERAND (RS1, *ip, imm_expr->X_add_number);
 	      imm_expr->X_op = O_absent;
-	      s = expr_end;
+	      asarg = expr_end;
 	      continue;
 
 	    case 'E': /* Control register.  */
 	      insn_with_csr = true;
 	      explicit_priv_attr = true;
-	      if (reg_lookup (&s, RCLASS_CSR, &regno))
+	      if (reg_lookup (&asarg, RCLASS_CSR, &regno))
 		INSERT_OPERAND (CSR, *ip, regno);
 	      else
 		{
-		  my_getExpression (imm_expr, s);
+		  my_getExpression (imm_expr, asarg);
 		  check_absolute_expr (ip, imm_expr, true);
 		  if ((unsigned long) imm_expr->X_add_number > 0xfff)
 		    as_bad (_("improper CSR address (%lu)"),
 			    (unsigned long) imm_expr->X_add_number);
 		  INSERT_OPERAND (CSR, *ip, imm_expr->X_add_number);
 		  imm_expr->X_op = O_absent;
-		  s = expr_end;
+		  asarg = expr_end;
 		}
 	      continue;
 
 	    case 'm': /* Rounding mode.  */
-	      if (arg_lookup (&s, riscv_rm, ARRAY_SIZE (riscv_rm), &regno))
+	      if (arg_lookup (&asarg, riscv_rm,
+			      ARRAY_SIZE (riscv_rm), &regno))
 		{
 		  INSERT_OPERAND (RM, *ip, regno);
 		  continue;
@@ -2487,10 +2649,10 @@ riscv_ip (char *str, struct riscv_cl_insn *ip, expressionS *imm_expr,
 
 	    case 'P':
 	    case 'Q': /* Fence predecessor/successor.  */
-	      if (arg_lookup (&s, riscv_pred_succ, ARRAY_SIZE (riscv_pred_succ),
-			      &regno))
+	      if (arg_lookup (&asarg, riscv_pred_succ,
+			      ARRAY_SIZE (riscv_pred_succ), &regno))
 		{
-		  if (*args == 'P')
+		  if (*oparg == 'P')
 		    INSERT_OPERAND (PRED, *ip, regno);
 		  else
 		    INSERT_OPERAND (SUCC, *ip, regno);
@@ -2502,11 +2664,11 @@ riscv_ip (char *str, struct riscv_cl_insn *ip, expressionS *imm_expr,
 	    case 's': /* Source register.  */
 	    case 't': /* Target register.  */
 	    case 'r': /* RS3 */
-	      if (reg_lookup (&s, RCLASS_GPR, &regno))
+	      if (reg_lookup (&asarg, RCLASS_GPR, &regno))
 		{
-		  c = *args;
-		  if (*s == ' ')
-		    ++s;
+		  char c = *oparg;
+		  if (*asarg == ' ')
+		    ++asarg;
 
 		  /* Now that we have assembled one operand, we use the args
 		     string to figure out where it goes in the instruction.  */
@@ -2534,11 +2696,12 @@ riscv_ip (char *str, struct riscv_cl_insn *ip, expressionS *imm_expr,
 	    case 'T': /* Floating point RS2.  */
 	    case 'U': /* Floating point RS1 and RS2.  */
 	    case 'R': /* Floating point RS3.  */
-	      if (reg_lookup (&s, RCLASS_FPR, &regno))
+	      if (reg_lookup (&asarg, RCLASS_FPR, &regno))
 		{
-		  c = *args;
-		  if (*s == ' ')
-		    ++s;
+		  char c = *oparg;
+		  if (*asarg == ' ')
+		    ++asarg;
+
 		  switch (c)
 		    {
 		    case 'D':
@@ -2562,33 +2725,33 @@ riscv_ip (char *str, struct riscv_cl_insn *ip, expressionS *imm_expr,
 	      break;
 
 	    case 'I':
-	      my_getExpression (imm_expr, s);
+	      my_getExpression (imm_expr, asarg);
 	      if (imm_expr->X_op != O_big
 		  && imm_expr->X_op != O_constant)
 		break;
 	      normalize_constant_expr (imm_expr);
-	      s = expr_end;
+	      asarg = expr_end;
 	      continue;
 
 	    case 'A':
-	      my_getExpression (imm_expr, s);
+	      my_getExpression (imm_expr, asarg);
 	      normalize_constant_expr (imm_expr);
 	      /* The 'A' format specifier must be a symbol.  */
 	      if (imm_expr->X_op != O_symbol)
 	        break;
 	      *imm_reloc = BFD_RELOC_32;
-	      s = expr_end;
+	      asarg = expr_end;
 	      continue;
 
 	    case 'B':
-	      my_getExpression (imm_expr, s);
+	      my_getExpression (imm_expr, asarg);
 	      normalize_constant_expr (imm_expr);
 	      /* The 'B' format specifier must be a symbol or a constant.  */
 	      if (imm_expr->X_op != O_symbol && imm_expr->X_op != O_constant)
 	        break;
 	      if (imm_expr->X_op == O_symbol)
 	        *imm_reloc = BFD_RELOC_32;
-	      s = expr_end;
+	      asarg = expr_end;
 	      continue;
 
 	    case 'j': /* Sign-extended immediate.  */
@@ -2612,35 +2775,35 @@ riscv_ip (char *str, struct riscv_cl_insn *ip, expressionS *imm_expr,
 	    case '0': /* AMO displacement, which must be zero.  */
 	      p = percent_op_null;
 	    load_store:
-	      if (riscv_handle_implicit_zero_offset (imm_expr, s))
+	      if (riscv_handle_implicit_zero_offset (imm_expr, asarg))
 		continue;
 	    alu_op:
 	      /* If this value won't fit into a 16 bit offset, then go
 		 find a macro that will generate the 32 bit offset
 		 code pattern.  */
-	      if (!my_getSmallExpression (imm_expr, imm_reloc, s, p))
+	      if (!my_getSmallExpression (imm_expr, imm_reloc, asarg, p))
 		{
 		  normalize_constant_expr (imm_expr);
 		  if (imm_expr->X_op != O_constant
-		      || (*args == '0' && imm_expr->X_add_number != 0)
-		      || (*args == '1')
+		      || (*oparg == '0' && imm_expr->X_add_number != 0)
+		      || (*oparg == '1')
 		      || imm_expr->X_add_number >= (signed)RISCV_IMM_REACH/2
 		      || imm_expr->X_add_number < -(signed)RISCV_IMM_REACH/2)
 		    break;
 		}
-	      s = expr_end;
+	      asarg = expr_end;
 	      continue;
 
 	    case 'p': /* PC-relative offset.  */
 	    branch:
 	      *imm_reloc = BFD_RELOC_12_PCREL;
-	      my_getExpression (imm_expr, s);
-	      s = expr_end;
+	      my_getExpression (imm_expr, asarg);
+	      asarg = expr_end;
 	      continue;
 
 	    case 'u': /* Upper 20 bits.  */
 	      p = percent_op_utype;
-	      if (!my_getSmallExpression (imm_expr, imm_reloc, s, p))
+	      if (!my_getSmallExpression (imm_expr, imm_reloc, asarg, p))
 		{
 		  if (imm_expr->X_op != O_constant)
 		    break;
@@ -2652,33 +2815,33 @@ riscv_ip (char *str, struct riscv_cl_insn *ip, expressionS *imm_expr,
 		  *imm_reloc = BFD_RELOC_RISCV_HI20;
 		  imm_expr->X_add_number <<= RISCV_IMM_BITS;
 		}
-	      s = expr_end;
+	      asarg = expr_end;
 	      continue;
 
 	    case 'a': /* 20-bit PC-relative offset.  */
 	    jump:
-	      my_getExpression (imm_expr, s);
-	      s = expr_end;
+	      my_getExpression (imm_expr, asarg);
+	      asarg = expr_end;
 	      *imm_reloc = BFD_RELOC_RISCV_JMP;
 	      continue;
 
 	    case 'c':
-	      my_getExpression (imm_expr, s);
-	      s = expr_end;
-	      if (strcmp (s, "@plt") == 0)
+	      my_getExpression (imm_expr, asarg);
+	      asarg = expr_end;
+	      if (strcmp (asarg, "@plt") == 0)
 		{
 		  *imm_reloc = BFD_RELOC_RISCV_CALL_PLT;
-		  s += 4;
+		  asarg += 4;
 		}
 	      else
 		*imm_reloc = BFD_RELOC_RISCV_CALL;
 	      continue;
 
 	    case 'O':
-	      switch (*++args)
+	      switch (*++oparg)
 		{
 		case '4':
-		  if (my_getOpcodeExpression (imm_expr, imm_reloc, s, p)
+		  if (my_getOpcodeExpression (imm_expr, imm_reloc, asarg, p)
 		      || imm_expr->X_op != O_constant
 		      || imm_expr->X_add_number < 0
 		      || imm_expr->X_add_number >= 128
@@ -2691,11 +2854,11 @@ riscv_ip (char *str, struct riscv_cl_insn *ip, expressionS *imm_expr,
 		    }
 		  INSERT_OPERAND (OP, *ip, imm_expr->X_add_number);
 		  imm_expr->X_op = O_absent;
-		  s = expr_end;
+		  asarg = expr_end;
 		  continue;
 
 		case '2':
-		  if (my_getOpcodeExpression (imm_expr, imm_reloc, s, p)
+		  if (my_getOpcodeExpression (imm_expr, imm_reloc, asarg, p)
 		      || imm_expr->X_op != O_constant
 		      || imm_expr->X_add_number < 0
 		      || imm_expr->X_add_number >= 3)
@@ -2706,20 +2869,19 @@ riscv_ip (char *str, struct riscv_cl_insn *ip, expressionS *imm_expr,
 		    }
 		  INSERT_OPERAND (OP2, *ip, imm_expr->X_add_number);
 		  imm_expr->X_op = O_absent;
-		  s = expr_end;
+		  asarg = expr_end;
 		  continue;
 
 		default:
-		  as_bad (_("internal: unknown opcode field "
-			    "specifier `O%c'"), *args);
+		  goto parse_extended_operand;
 		}
 	      break;
 
 	    case 'F':
-	      switch (*++args)
+	      switch (*++oparg)
 		{
 		case '7':
-		  if (my_getSmallExpression (imm_expr, imm_reloc, s, p)
+		  if (my_getSmallExpression (imm_expr, imm_reloc, asarg, p)
 		      || imm_expr->X_op != O_constant
 		      || imm_expr->X_add_number < 0
 		      || imm_expr->X_add_number >= 128)
@@ -2730,11 +2892,11 @@ riscv_ip (char *str, struct riscv_cl_insn *ip, expressionS *imm_expr,
 		    }
 		  INSERT_OPERAND (FUNCT7, *ip, imm_expr->X_add_number);
 		  imm_expr->X_op = O_absent;
-		  s = expr_end;
+		  asarg = expr_end;
 		  continue;
 
 		case '3':
-		  if (my_getSmallExpression (imm_expr, imm_reloc, s, p)
+		  if (my_getSmallExpression (imm_expr, imm_reloc, asarg, p)
 		      || imm_expr->X_op != O_constant
 		      || imm_expr->X_add_number < 0
 		      || imm_expr->X_add_number >= 8)
@@ -2745,11 +2907,11 @@ riscv_ip (char *str, struct riscv_cl_insn *ip, expressionS *imm_expr,
 		    }
 		  INSERT_OPERAND (FUNCT3, *ip, imm_expr->X_add_number);
 		  imm_expr->X_op = O_absent;
-		  s = expr_end;
+		  asarg = expr_end;
 		  continue;
 
 		case '2':
-		  if (my_getSmallExpression (imm_expr, imm_reloc, s, p)
+		  if (my_getSmallExpression (imm_expr, imm_reloc, asarg, p)
 		      || imm_expr->X_op != O_constant
 		      || imm_expr->X_add_number < 0
 		      || imm_expr->X_add_number >= 4)
@@ -2760,30 +2922,33 @@ riscv_ip (char *str, struct riscv_cl_insn *ip, expressionS *imm_expr,
 		    }
 		  INSERT_OPERAND (FUNCT2, *ip, imm_expr->X_add_number);
 		  imm_expr->X_op = O_absent;
-		  s = expr_end;
+		  asarg = expr_end;
 		  continue;
 
 		default:
-		  as_bad (_("internal: unknown funct field "
-			    "specifier `F%c'\n"), *args);
+		  goto parse_extended_operand;
 		}
 	      break;
 
 	    case 'z':
-	      if (my_getSmallExpression (imm_expr, imm_reloc, s, p)
+	      if (my_getSmallExpression (imm_expr, imm_reloc, asarg, p)
 		  || imm_expr->X_op != O_constant
 		  || imm_expr->X_add_number != 0)
 		break;
-	      s = expr_end;
+	      asarg = expr_end;
 	      imm_expr->X_op = O_absent;
 	      continue;
 
 	    default:
-	      as_fatal (_("internal: unknown argument type `%c'"), *args);
+	      parse_extended_operand:
+		oparg = opargStart;
+		if (riscv_parse_extended_operands (ip, imm_expr, imm_reloc,
+						   &oparg, &asarg))
+		  continue;
 	    }
 	  break;
 	}
-      s = argsStart;
+      asarg = asargStart;
       error = _("illegal operands");
       insn_with_csr = false;
     }
@@ -2791,7 +2956,7 @@ riscv_ip (char *str, struct riscv_cl_insn *ip, expressionS *imm_expr,
  out:
   /* Restore the character we might have clobbered above.  */
   if (save_c)
-    *(argsStart - 1) = save_c;
+    *(asargStart - 1) = save_c;
 
   return error;
 }
diff --git a/gas/testsuite/gas/riscv/extended/extended.exp b/gas/testsuite/gas/riscv/extended/extended.exp
new file mode 100644
index 00000000000..8767c848a1f
--- /dev/null
+++ b/gas/testsuite/gas/riscv/extended/extended.exp
@@ -0,0 +1,22 @@
+# Expect script for RISC-V assembler tests.
+# Copyright (C) 2021 Free Software Foundation, Inc.
+#
+# This file is part of the GNU Binutils.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
+# MA 02110-1301, USA.
+
+if [istarget riscv*-*-*] {
+}
diff --git a/include/opcode/riscv-opc-extended.h b/include/opcode/riscv-opc-extended.h
new file mode 100644
index 00000000000..c9c292aab5d
--- /dev/null
+++ b/include/opcode/riscv-opc-extended.h
@@ -0,0 +1,22 @@
+/* riscv-opcextended.h.  RISC-V extended instruction opcode.
+   Copyright (C) 2021 Free Software Foundation, Inc.
+
+   This file is part of GDB, GAS, and the GNU binutils.
+
+   GDB, GAS, and the GNU binutils are free software; you can redistribute
+   them and/or modify them under the terms of the GNU General Public
+   License as published by the Free Software Foundation; either version
+   3, or (at your option) any later version.
+
+   GDB, GAS, and the GNU binutils are distributed in the hope that they
+   will be useful, but WITHOUT ANY WARRANTY; without even the implied
+   warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
+   the GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; see the file COPYING3. If not,
+   see <http://www.gnu.org/licenses/>.  */
+
+#ifndef RISCV_EXTENDED_ENCODING_H
+#define RISCV_EXTENDED_ENCODING_H
+#endif /* RISCV_EXTENDED_ENCODING_H */
diff --git a/include/opcode/riscv.h b/include/opcode/riscv.h
index afcd41ff1dd..a336eb42489 100644
--- a/include/opcode/riscv.h
+++ b/include/opcode/riscv.h
@@ -22,6 +22,7 @@
 #define _RISCV_H_
 
 #include "riscv-opc.h"
+#include "riscv-opc-extended.h"
 #include <stdlib.h>
 #include <stdint.h>
 
@@ -303,7 +304,6 @@ static const char * const riscv_pred_succ[16] =
 enum riscv_insn_class
 {
   INSN_CLASS_NONE,
-
   INSN_CLASS_I,
   INSN_CLASS_C,
   INSN_CLASS_A,
@@ -320,6 +320,7 @@ enum riscv_insn_class
   INSN_CLASS_ZBB,
   INSN_CLASS_ZBC,
   INSN_CLASS_ZBS,
+  INSN_CLASS_EXTENDED
 };
 
 /* This structure holds information for a particular instruction.  */
@@ -333,7 +334,7 @@ struct riscv_opcode
 
   /* Class to which this instruction belongs.  Used to decide whether or
      not this instruction is legal in the current -march context.  */
-  enum riscv_insn_class insn_class;
+  int insn_class;
 
   /* A string describing the arguments for this instruction.  */
   const char *args;
@@ -423,7 +424,7 @@ enum
   M_ZEXTW,
   M_SEXTB,
   M_SEXTH,
-  M_NUM_MACROS
+  M_EXTENDED
 };
 
 /* The mapping symbol states.  */
@@ -442,4 +443,8 @@ extern const char * const riscv_fpr_names_abi[NFPR];
 extern const struct riscv_opcode riscv_opcodes[];
 extern const struct riscv_opcode riscv_insn_types[];
 
+/* Extended extensions.  */
+
+extern const struct riscv_opcode *riscv_extended_opcodes[];
+
 #endif /* _RISCV_H_ */
diff --git a/opcodes/riscv-dis.c b/opcodes/riscv-dis.c
index 2e28ba77e60..a9493a906d5 100644
--- a/opcodes/riscv-dis.c
+++ b/opcodes/riscv-dis.c
@@ -174,25 +174,46 @@ maybe_print_address (struct riscv_private_data *pd, int base_reg, int offset,
     pd->print_addr = (bfd_vma)(int32_t) pd->print_addr;
 }
 
+/* Print insn arguments for extended extensions.  */
+
+static bool
+print_extended_insn_args (const char **opcode_args,
+			  insn_t l ATTRIBUTE_UNUSED,
+			  disassemble_info *info ATTRIBUTE_UNUSED)
+{
+  const char *oparg = *opcode_args;
+
+  switch (*oparg)
+    {
+    default:
+      return false;
+    }
+
+  *opcode_args = oparg;
+  return true;
+}
+
 /* Print insn arguments for 32/64-bit code.  */
 
 static void
-print_insn_args (const char *d, insn_t l, bfd_vma pc, disassemble_info *info)
+print_insn_args (const char *oparg, insn_t l, bfd_vma pc, disassemble_info *info)
 {
   struct riscv_private_data *pd = info->private_data;
   int rs1 = (l >> OP_SH_RS1) & OP_MASK_RS1;
   int rd = (l >> OP_SH_RD) & OP_MASK_RD;
   fprintf_ftype print = info->fprintf_func;
+  const char *opargStart;
 
-  if (*d != '\0')
+  if (*oparg != '\0')
     print (info->stream, "\t");
 
-  for (; *d != '\0'; d++)
+  for (; *oparg != '\0'; oparg++)
     {
-      switch (*d)
+      opargStart = oparg;
+      switch (*oparg)
 	{
 	case 'C': /* RVC */
-	  switch (*++d)
+	  switch (*++oparg)
 	    {
 	    case 's': /* RS1 x8-x15.  */
 	    case 'w': /* RS1 x8-x15.  */
@@ -281,12 +302,12 @@ print_insn_args (const char *d, insn_t l, bfd_vma pc, disassemble_info *info)
 	case ')':
 	case '[':
 	case ']':
-	  print (info->stream, "%c", *d);
+	  print (info->stream, "%c", *oparg);
 	  break;
 
 	case '0':
 	  /* Only print constant 0 if it is the last argument.  */
-	  if (!d[1])
+	  if (!oparg[1])
 	    print (info->stream, "0");
 	  break;
 
@@ -415,6 +436,7 @@ print_insn_args (const char *d, insn_t l, bfd_vma pc, disassemble_info *info)
 #define DECLARE_CSR_ALIAS(name, num, class, define_version, abort_version) \
 		DECLARE_CSR (name, num, class, define_version, abort_version)
 #include "opcode/riscv-opc.h"
+#include "opcode/riscv-opc-extended.h"
 #undef DECLARE_CSR
 	      }
 
@@ -430,31 +452,34 @@ print_insn_args (const char *d, insn_t l, bfd_vma pc, disassemble_info *info)
 	  break;
 
 	default:
-	  /* xgettext:c-format */
-	  print (info->stream, _("# internal error, undefined modifier (%c)"),
-		 *d);
-	  return;
+	  oparg = opargStart;
+	  if (!print_extended_insn_args (&oparg, l, info))
+	    {
+	      /* xgettext:c-format */
+	      print (info->stream,
+		     _("# internal error, undefined modifier (%s)"), opargStart);
+	      return;
+	    }
 	}
     }
 }
 
-/* Print the RISC-V instruction at address MEMADDR in debugged memory,
-   on using INFO.  Returns length of the instruction, in bytes.
-   BIGENDIAN must be 1 if this is big-endian code, 0 if
-   this is little-endian code.  */
+/* Find the right opcode name when disassembling.  */
 
-static int
-riscv_disassemble_insn (bfd_vma memaddr, insn_t word, disassemble_info *info)
+static const struct riscv_opcode *
+riscv_disassemble_opcode (insn_t word,
+			  disassemble_info *info)
 {
+  static const struct riscv_opcode *riscv_hash[OP_MASK_OP + 1];
   const struct riscv_opcode *op;
   static bool init = 0;
-  static const struct riscv_opcode *riscv_hash[OP_MASK_OP + 1];
-  struct riscv_private_data *pd;
-  int insnlen;
+  unsigned xlen = 0;
+  unsigned int i;
 
 #define OP_HASH_IDX(i) ((i) & (riscv_insn_length (i) == 2 ? 0x3 : OP_MASK_OP))
 
-  /* Build a hash table to shorten the search time.  */
+  /* Build a hash table to shorten the search time.  For now we just build
+     the hash for the standard instructions.  */
   if (! init)
     {
       for (op = riscv_opcodes; op->name; op++)
@@ -464,6 +489,61 @@ riscv_disassemble_insn (bfd_vma memaddr, insn_t word, disassemble_info *info)
       init = 1;
     }
 
+  /* Search the standard instructions first.  */
+  op = riscv_hash[OP_HASH_IDX (word)];
+  i = 0;
+  do
+    {
+      /* The hash table entry might be NULL.  */
+      if (op != NULL)
+	{
+	  /* If XLEN is not known, get its value from the ELF class.  */
+	  if (info->mach == bfd_mach_riscv64)
+	    xlen = 64;
+	  else if (info->mach == bfd_mach_riscv32)
+	    xlen = 32;
+	  else if (info->section != NULL)
+	    {
+	      Elf_Internal_Ehdr *ehdr = elf_elfheader (info->section->owner);
+	      xlen = ehdr->e_ident[EI_CLASS] == ELFCLASS64 ? 64 : 32;
+	    }
+
+	  for (; op->name; op++)
+	    {
+	      /* Does the opcode match?  */
+	      if (! (op->match_func) (op, word))
+		continue;
+	      /* Is this a pseudo-instruction and may we print it as such?  */
+	      if (no_aliases && (op->pinfo & INSN_ALIAS))
+		continue;
+	      /* Is this instruction restricted to a certain value of XLEN?  */
+	      if ((op->xlen_requirement != 0) && (op->xlen_requirement != xlen))
+		continue;
+
+	      /* It's a match.  */
+	      return op;
+	    }
+	}
+      /* Keep searching extended opcode tables.  */
+      op = riscv_extended_opcodes[i++];
+    }
+  while (op != NULL);
+
+  return NULL;
+}
+
+/* Print the RISC-V instruction at address MEMADDR in debugged memory,
+   on using INFO.  Returns length of the instruction, in bytes.
+   BIGENDIAN must be 1 if this is big-endian code, 0 if
+   this is little-endian code.  */
+
+static int
+riscv_disassemble_insn (bfd_vma memaddr, insn_t word, disassemble_info *info)
+{
+  const struct riscv_opcode *op;
+  struct riscv_private_data *pd;
+  int insnlen;
+
   if (info->private_data == NULL)
     {
       int i;
@@ -497,75 +577,48 @@ riscv_disassemble_insn (bfd_vma memaddr, insn_t word, disassemble_info *info)
   info->target = 0;
   info->target2 = 0;
 
-  op = riscv_hash[OP_HASH_IDX (word)];
+  op = riscv_disassemble_opcode (word, info);
   if (op != NULL)
     {
-      unsigned xlen = 0;
-
-      /* If XLEN is not known, get its value from the ELF class.  */
-      if (info->mach == bfd_mach_riscv64)
-	xlen = 64;
-      else if (info->mach == bfd_mach_riscv32)
-	xlen = 32;
-      else if (info->section != NULL)
+      (*info->fprintf_func) (info->stream, "%s", op->name);
+      print_insn_args (op->args, word, memaddr, info);
+
+      /* Try to disassemble multi-instruction addressing sequences.  */
+      if (pd->print_addr != (bfd_vma)-1)
 	{
-	  Elf_Internal_Ehdr *ehdr = elf_elfheader (info->section->owner);
-	  xlen = ehdr->e_ident[EI_CLASS] == ELFCLASS64 ? 64 : 32;
+	  info->target = pd->print_addr;
+	  (*info->fprintf_func) (info->stream, " # ");
+	  (*info->print_address_func) (info->target, info);
+	  pd->print_addr = -1;
 	}
 
-      for (; op->name; op++)
+      /* Finish filling out insn_info fields.  */
+      switch (op->pinfo & INSN_TYPE)
 	{
-	  /* Does the opcode match?  */
-	  if (! (op->match_func) (op, word))
-	    continue;
-	  /* Is this a pseudo-instruction and may we print it as such?  */
-	  if (no_aliases && (op->pinfo & INSN_ALIAS))
-	    continue;
-	  /* Is this instruction restricted to a certain value of XLEN?  */
-	  if ((op->xlen_requirement != 0) && (op->xlen_requirement != xlen))
-	    continue;
-
-	  /* It's a match.  */
-	  (*info->fprintf_func) (info->stream, "%s", op->name);
-	  print_insn_args (op->args, word, memaddr, info);
-
-	  /* Try to disassemble multi-instruction addressing sequences.  */
-	  if (pd->print_addr != (bfd_vma)-1)
-	    {
-	      info->target = pd->print_addr;
-	      (*info->fprintf_func) (info->stream, " # ");
-	      (*info->print_address_func) (info->target, info);
-	      pd->print_addr = -1;
-	    }
-
-	  /* Finish filling out insn_info fields.  */
-	  switch (op->pinfo & INSN_TYPE)
-	    {
-	    case INSN_BRANCH:
-	      info->insn_type = dis_branch;
-	      break;
-	    case INSN_CONDBRANCH:
-	      info->insn_type = dis_condbranch;
-	      break;
-	    case INSN_JSR:
-	      info->insn_type = dis_jsr;
-	      break;
-	    case INSN_DREF:
-	      info->insn_type = dis_dref;
-	      break;
-	    default:
-	      break;
-	    }
-
-	  if (op->pinfo & INSN_DATA_SIZE)
-	    {
-	      int size = ((op->pinfo & INSN_DATA_SIZE)
-			  >> INSN_DATA_SIZE_SHIFT);
-	      info->data_size = 1 << (size - 1);
-	    }
+	case INSN_BRANCH:
+	  info->insn_type = dis_branch;
+	  break;
+	case INSN_CONDBRANCH:
+	  info->insn_type = dis_condbranch;
+	  break;
+	case INSN_JSR:
+	  info->insn_type = dis_jsr;
+	  break;
+	case INSN_DREF:
+	  info->insn_type = dis_dref;
+	  break;
+	default:
+	  break;
+	}
 
-	  return insnlen;
+      if (op->pinfo & INSN_DATA_SIZE)
+	{
+	  int size = ((op->pinfo & INSN_DATA_SIZE)
+		      >> INSN_DATA_SIZE_SHIFT);
+	  info->data_size = 1 << (size - 1);
 	}
+
+      return insnlen;
     }
 
   /* We did not find a match, so just print the instruction bits.  */
diff --git a/opcodes/riscv-opc.c b/opcodes/riscv-opc.c
index b756bae64ab..8eab2316287 100644
--- a/opcodes/riscv-opc.c
+++ b/opcodes/riscv-opc.c
@@ -961,3 +961,11 @@ const struct riscv_opcode riscv_insn_types[] =
 /* Terminate the list.  */
 {0, 0, INSN_CLASS_NONE, 0, 0, 0, 0, 0}
 };
+
+/* Extended extensions.  */
+
+/* The supported extended extensions.  */
+const struct riscv_opcode *riscv_extended_opcodes[] =
+{
+  NULL
+};