[AArch64][SVE 30/32] Add SVE instruction classes

The main purpose of the SVE aarch64_insn_classes is to describe how
an index into an aarch64_opnd_qualifier_seq_t is represented in the
instruction encoding.  Other instructions usually use flags for this
information, but (a) we're running out of those and (b) the iclass
would otherwise be unused for SVE.

include/
	* opcode/aarch64.h (sve_cpy, sve_index, sve_limm, sve_misc)
	(sve_movprfx, sve_pred_zm, sve_shift_pred, sve_shift_unpred)
	(sve_size_bhs, sve_size_bhsd, sve_size_hsd, sve_size_sd): New
	aarch64_insn_classes.

opcodes/
	* aarch64-opc.h (FLD_SVE_M_4, FLD_SVE_M_14, FLD_SVE_M_16)
	(FLD_SVE_sz, FLD_SVE_tsz, FLD_SVE_tszl_8, FLD_SVE_tszl_19): New
	aarch64_field_kinds.
	* aarch64-opc.c (fields): Add corresponding entries.
	* aarch64-asm.c (aarch64_get_variant): New function.
	(aarch64_encode_variant_using_iclass): Likewise.
	(aarch64_opcode_encode): Call it.
	* aarch64-dis.c (aarch64_decode_variant_using_iclass): New function.
	(aarch64_opcode_decode): Call it.

5 files changed, 217 insertions, 0 deletions

diff --git a/opcodes/ChangeLog b/opcodes/ChangeLog
index 967de6f..8670587 100644
--- a/opcodes/ChangeLog
+++ b/opcodes/ChangeLog
@@ -1,5 +1,17 @@
 2016-09-21  Richard Sandiford  <richard.sandiford@arm.com>
 
+	* aarch64-opc.h (FLD_SVE_M_4, FLD_SVE_M_14, FLD_SVE_M_16)
+	(FLD_SVE_sz, FLD_SVE_tsz, FLD_SVE_tszl_8, FLD_SVE_tszl_19): New
+	aarch64_field_kinds.
+	* aarch64-opc.c (fields): Add corresponding entries.
+	* aarch64-asm.c (aarch64_get_variant): New function.
+	(aarch64_encode_variant_using_iclass): Likewise.
+	(aarch64_opcode_encode): Call it.
+	* aarch64-dis.c (aarch64_decode_variant_using_iclass): New function.
+	(aarch64_opcode_decode): Call it.
+
+2016-09-21  Richard Sandiford  <richard.sandiford@arm.com>
+
 	* aarch64-tbl.h (AARCH64_OPERANDS): Add entries for the new SVE core
 	and FP register operands.
 	* aarch64-opc.h (FLD_SVE_Rm, FLD_SVE_Rn, FLD_SVE_Vd, FLD_SVE_Vm)
diff --git a/opcodes/aarch64-asm.c b/opcodes/aarch64-asm.c
index fd356f4..78fd272 100644
--- a/opcodes/aarch64-asm.c
+++ b/opcodes/aarch64-asm.c
@@ -1140,6 +1140,27 @@ encode_fcvt (aarch64_inst *inst)
   return;
 }
 
+/* Return the index in qualifiers_list that INST is using.  Should only
+   be called once the qualifiers are known to be valid.  */
+
+static int
+aarch64_get_variant (struct aarch64_inst *inst)
+{
+  int i, nops, variant;
+
+  nops = aarch64_num_of_operands (inst->opcode);
+  for (variant = 0; variant < AARCH64_MAX_QLF_SEQ_NUM; ++variant)
+    {
+      for (i = 0; i < nops; ++i)
+	if (inst->opcode->qualifiers_list[variant][i]
+	    != inst->operands[i].qualifier)
+	  break;
+      if (i == nops)
+	return variant;
+    }
+  abort ();
+}
+
 /* Do miscellaneous encodings that are not common enough to be driven by
    flags.  */
 
@@ -1318,6 +1339,65 @@ do_special_encoding (struct aarch64_inst *inst)
   DEBUG_TRACE ("exit with coding 0x%x", (uint32_t) inst->value);
 }
 
+/* Some instructions (including all SVE ones) use the instruction class
+   to describe how a qualifiers_list index is represented in the instruction
+   encoding.  If INST is such an instruction, encode the chosen qualifier
+   variant.  */
+
+static void
+aarch64_encode_variant_using_iclass (struct aarch64_inst *inst)
+{
+  switch (inst->opcode->iclass)
+    {
+    case sve_cpy:
+      insert_fields (&inst->value, aarch64_get_variant (inst),
+		     0, 2, FLD_SVE_M_14, FLD_size);
+      break;
+
+    case sve_index:
+    case sve_shift_pred:
+    case sve_shift_unpred:
+      /* For indices and shift amounts, the variant is encoded as
+	 part of the immediate.  */
+      break;
+
+    case sve_limm:
+      /* For sve_limm, the .B, .H, and .S forms are just a convenience
+	 and depend on the immediate.  They don't have a separate
+	 encoding.  */
+      break;
+
+    case sve_misc:
+      /* sve_misc instructions have only a single variant.  */
+      break;
+
+    case sve_movprfx:
+      insert_fields (&inst->value, aarch64_get_variant (inst),
+		     0, 2, FLD_SVE_M_16, FLD_size);
+      break;
+
+    case sve_pred_zm:
+      insert_field (FLD_SVE_M_4, &inst->value, aarch64_get_variant (inst), 0);
+      break;
+
+    case sve_size_bhs:
+    case sve_size_bhsd:
+      insert_field (FLD_size, &inst->value, aarch64_get_variant (inst), 0);
+      break;
+
+    case sve_size_hsd:
+      insert_field (FLD_size, &inst->value, aarch64_get_variant (inst) + 1, 0);
+      break;
+
+    case sve_size_sd:
+      insert_field (FLD_SVE_sz, &inst->value, aarch64_get_variant (inst), 0);
+      break;
+
+    default:
+      break;
+    }
+}
+
 /* Converters converting an alias opcode instruction to its real form.  */
 
 /* ROR <Wd>, <Ws>, #<shift>
@@ -1686,6 +1766,10 @@ aarch64_opcode_encode (const aarch64_opcode *opcode,
   if (opcode_has_special_coder (opcode))
     do_special_encoding (inst);
 
+  /* Possibly use the instruction class to encode the chosen qualifier
+     variant.  */
+  aarch64_encode_variant_using_iclass (inst);
+
 encoding_exit:
   DEBUG_TRACE ("exit with %s", opcode->name);
 
diff --git a/opcodes/aarch64-dis.c b/opcodes/aarch64-dis.c
index 385286c..f84f216 100644
--- a/opcodes/aarch64-dis.c
+++ b/opcodes/aarch64-dis.c
@@ -2444,6 +2444,105 @@ determine_disassembling_preference (struct aarch64_inst *inst)
     }
 }
 
+/* Some instructions (including all SVE ones) use the instruction class
+   to describe how a qualifiers_list index is represented in the instruction
+   encoding.  If INST is such an instruction, decode the appropriate fields
+   and fill in the operand qualifiers accordingly.  Return true if no
+   problems are found.  */
+
+static bfd_boolean
+aarch64_decode_variant_using_iclass (aarch64_inst *inst)
+{
+  int i, variant;
+
+  variant = 0;
+  switch (inst->opcode->iclass)
+    {
+    case sve_cpy:
+      variant = extract_fields (inst->value, 0, 2, FLD_size, FLD_SVE_M_14);
+      break;
+
+    case sve_index:
+      i = extract_field (FLD_SVE_tsz, inst->value, 0);
+      if (i == 0)
+	return FALSE;
+      while ((i & 1) == 0)
+	{
+	  i >>= 1;
+	  variant += 1;
+	}
+      break;
+
+    case sve_limm:
+      /* Pick the smallest applicable element size.  */
+      if ((inst->value & 0x20600) == 0x600)
+	variant = 0;
+      else if ((inst->value & 0x20400) == 0x400)
+	variant = 1;
+      else if ((inst->value & 0x20000) == 0)
+	variant = 2;
+      else
+	variant = 3;
+      break;
+
+    case sve_misc:
+      /* sve_misc instructions have only a single variant.  */
+      break;
+
+    case sve_movprfx:
+      variant = extract_fields (inst->value, 0, 2, FLD_size, FLD_SVE_M_16);
+      break;
+
+    case sve_pred_zm:
+      variant = extract_field (FLD_SVE_M_4, inst->value, 0);
+      break;
+
+    case sve_shift_pred:
+      i = extract_fields (inst->value, 0, 2, FLD_SVE_tszh, FLD_SVE_tszl_8);
+    sve_shift:
+      if (i == 0)
+	return FALSE;
+      while (i != 1)
+	{
+	  i >>= 1;
+	  variant += 1;
+	}
+      break;
+
+    case sve_shift_unpred:
+      i = extract_fields (inst->value, 0, 2, FLD_SVE_tszh, FLD_SVE_tszl_19);
+      goto sve_shift;
+
+    case sve_size_bhs:
+      variant = extract_field (FLD_size, inst->value, 0);
+      if (variant >= 3)
+	return FALSE;
+      break;
+
+    case sve_size_bhsd:
+      variant = extract_field (FLD_size, inst->value, 0);
+      break;
+
+    case sve_size_hsd:
+      i = extract_field (FLD_size, inst->value, 0);
+      if (i < 1)
+	return FALSE;
+      variant = i - 1;
+      break;
+
+    case sve_size_sd:
+      variant = extract_field (FLD_SVE_sz, inst->value, 0);
+      break;
+
+    default:
+      /* No mapping between instruction class and qualifiers.  */
+      return TRUE;
+    }
+
+  for (i = 0; i < AARCH64_MAX_OPND_NUM; ++i)
+    inst->operands[i].qualifier = inst->opcode->qualifiers_list[variant][i];
+  return TRUE;
+}
 /* Decode the CODE according to OPCODE; fill INST.  Return 0 if the decoding
    fails, which meanes that CODE is not an instruction of OPCODE; otherwise
    return 1.
@@ -2491,6 +2590,14 @@ aarch64_opcode_decode (const aarch64_opcode *opcode, const aarch64_insn code,
       goto decode_fail;
     }
 
+  /* Possibly use the instruction class to determine the correct
+     qualifier.  */
+  if (!aarch64_decode_variant_using_iclass (inst))
+    {
+      DEBUG_TRACE ("iclass-based decoder FAIL");
+      goto decode_fail;
+    }
+
   /* Call operand decoders.  */
   for (i = 0; i < AARCH64_MAX_OPND_NUM; ++i)
     {
diff --git a/opcodes/aarch64-opc.c b/opcodes/aarch64-opc.c
index 47c5079..d22e419 100644
--- a/opcodes/aarch64-opc.c
+++ b/opcodes/aarch64-opc.c
@@ -264,6 +264,9 @@ const aarch64_field fields[] =
     { 31,  1 },	/* b5: in the test bit and branch instructions.  */
     { 19,  5 },	/* b40: in the test bit and branch instructions.  */
     { 10,  6 },	/* scale: in the fixed-point scalar to fp converting inst.  */
+    {  4,  1 }, /* SVE_M_4: Merge/zero select, bit 4.  */
+    { 14,  1 }, /* SVE_M_14: Merge/zero select, bit 14.  */
+    { 16,  1 }, /* SVE_M_16: Merge/zero select, bit 16.  */
     { 17,  1 }, /* SVE_N: SVE equivalent of N.  */
     {  0,  4 }, /* SVE_Pd: p0-p15, bits [3,0].  */
     { 10,  3 }, /* SVE_Pg3: p0-p7, bits [12,10].  */
@@ -299,7 +302,11 @@ const aarch64_field fields[] =
     { 10,  2 }, /* SVE_msz: 2-bit shift amount for ADR.  */
     {  5,  5 }, /* SVE_pattern: vector pattern enumeration.  */
     {  0,  4 }, /* SVE_prfop: prefetch operation for SVE PRF[BHWD].  */
+    { 22,  1 }, /* SVE_sz: 1-bit element size select.  */
+    { 16,  4 }, /* SVE_tsz: triangular size select.  */
     { 22,  2 }, /* SVE_tszh: triangular size select high, bits [23,22].  */
+    {  8,  2 }, /* SVE_tszl_8: triangular size select low, bits [9,8].  */
+    { 19,  2 }, /* SVE_tszl_19: triangular size select low, bits [20,19].  */
     { 14,  1 }, /* SVE_xs_14: UXTW/SXTW select (bit 14).  */
     { 22,  1 }  /* SVE_xs_22: UXTW/SXTW select (bit 22).  */
 };
diff --git a/opcodes/aarch64-opc.h b/opcodes/aarch64-opc.h
index a7654d0..0c3d90e 100644
--- a/opcodes/aarch64-opc.h
+++ b/opcodes/aarch64-opc.h
@@ -91,6 +91,9 @@ enum aarch64_field_kind
   FLD_b5,
   FLD_b40,
   FLD_scale,
+  FLD_SVE_M_4,
+  FLD_SVE_M_14,
+  FLD_SVE_M_16,
   FLD_SVE_N,
   FLD_SVE_Pd,
   FLD_SVE_Pg3,
@@ -126,7 +129,11 @@ enum aarch64_field_kind
   FLD_SVE_msz,
   FLD_SVE_pattern,
   FLD_SVE_prfop,
+  FLD_SVE_sz,
+  FLD_SVE_tsz,
   FLD_SVE_tszh,
+  FLD_SVE_tszl_8,
+  FLD_SVE_tszl_19,
   FLD_SVE_xs_14,
   FLD_SVE_xs_22,
 };