/* alpha-dis.c -- Disassemble Alpha AXP instructions

   Copyright (C) 1996-2026 Free Software Foundation, Inc.

   Contributed by Richard Henderson <rth@tamu.edu>,

   patterned after the PPC opcode handling written by Ian Lance Taylor.

   This file is part of libopcodes.

   This library 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, or (at your option)

   any later version.

   It 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 file; see the file COPYING.  If not, write to the Free

   Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA

   02110-1301, USA.  */

#include "sysdep.h"

#include <stdio.h>

#include "disassemble.h"

#include "opcode/alpha.h"

/* OSF register names.  */

static const char * const osf_regnames[64] = {

  "v0", "t0", "t1", "t2", "t3", "t4", "t5", "t6",

  "t7", "s0", "s1", "s2", "s3", "s4", "s5", "fp",

  "a0", "a1", "a2", "a3", "a4", "a5", "t8", "t9",

  "t10", "t11", "ra", "t12", "at", "gp", "sp", "zero",

  "$f0", "$f1", "$f2", "$f3", "$f4", "$f5", "$f6", "$f7",

  "$f8", "$f9", "$f10", "$f11", "$f12", "$f13", "$f14", "$f15",

  "$f16", "$f17", "$f18", "$f19", "$f20", "$f21", "$f22", "$f23",

  "$f24", "$f25", "$f26", "$f27", "$f28", "$f29", "$f30", "$f31"

};

/* VMS register names.  */

static const char * const vms_regnames[64] = {

  "R0", "R1", "R2", "R3", "R4", "R5", "R6", "R7",

  "R8", "R9", "R10", "R11", "R12", "R13", "R14", "R15",

  "R16", "R17", "R18", "R19", "R20", "R21", "R22", "R23",

  "R24", "AI", "RA", "PV", "AT", "FP", "SP", "RZ",

  "F0", "F1", "F2", "F3", "F4", "F5", "F6", "F7",

  "F8", "F9", "F10", "F11", "F12", "F13", "F14", "F15",

  "F16", "F17", "F18", "F19", "F20", "F21", "F22", "F23",

  "F24", "F25", "F26", "F27", "F28", "F29", "F30", "FZ"

};

/* Disassemble Alpha instructions.  */

int

print_insn_alpha (bfd_vma memaddr, struct disassemble_info *info)

{

  static const struct alpha_opcode *opcode_index[AXP_NOPS+1];

  const char * const * regnames;

  const struct alpha_opcode *opcode, *opcode_end;

  const unsigned char *opindex;

  unsigned insn, op, isa_mask;

  int need_comma;

  /* Initialize the majorop table the first time through */

  if (!opcode_index[0])

    {

      opcode = alpha_opcodes;

      opcode_end = opcode + alpha_num_opcodes;

      for (op = 0; op < AXP_NOPS; ++op)

  {

    opcode_index[op] = opcode;

    while (opcode < opcode_end && op == AXP_OP (opcode->opcode))

      ++opcode;

  }

      opcode_index[op] = opcode;

    }

  if (info->flavour == bfd_target_evax_flavour)

    regnames = vms_regnames;

  else

    regnames = osf_regnames;

  isa_mask = AXP_OPCODE_NOPAL;

  switch (info->mach)

    {

    case bfd_mach_alpha_ev4:

      isa_mask |= AXP_OPCODE_EV4;

      break;

    case bfd_mach_alpha_ev5:

      isa_mask |= AXP_OPCODE_EV5;

      break;

    case bfd_mach_alpha_ev6:

      isa_mask |= AXP_OPCODE_EV6;

      break;

    }

  /* Read the insn into a host word */

  {

    bfd_byte buffer[4];

    int status = (*info->read_memory_func) (memaddr, buffer, 4, info);

    if (status != 0)

      {

  (*info->memory_error_func) (status, memaddr, info);

  return -1;

      }

    insn = bfd_getl32 (buffer);

  }

  /* Get the major opcode of the instruction.  */

  op = AXP_OP (insn);

  /* Find the first match in the opcode table.  */

  opcode_end = opcode_index[op + 1];

  for (opcode = opcode_index[op]; opcode < opcode_end; ++opcode)

    {

      if ((insn ^ opcode->opcode) & opcode->mask)

  continue;

      if (!(opcode->flags & isa_mask))

  continue;

      /* Make two passes over the operands.  First see if any of them

   have extraction functions, and, if they do, make sure the

   instruction is valid.  */

      {

  int invalid = 0;

  for (opindex = opcode->operands; *opindex != 0; opindex++)

    {

      const struct alpha_operand *operand = alpha_operands + *opindex;

      if (operand->extract)

        (*operand->extract) (insn, &invalid);

    }

  if (invalid)

    continue;

      }

      /* The instruction is valid.  */

      goto found;

    }

  /* No instruction found */

  (*info->fprintf_func) (info->stream, ".long %#08x", insn);

  return 4;

 found:

  (*info->fprintf_func) (info->stream, "%s", opcode->name);

  if (opcode->operands[0] != 0)

    (*info->fprintf_func) (info->stream, "\t");

  /* Now extract and print the operands.  */

  need_comma = 0;

  for (opindex = opcode->operands; *opindex != 0; opindex++)

    {

      const struct alpha_operand *operand = alpha_operands + *opindex;

      int value;

      /* Operands that are marked FAKE are simply ignored.  We

   already made sure that the extract function considered

   the instruction to be valid.  */

      if ((operand->flags & AXP_OPERAND_FAKE) != 0)

  continue;

      /* Extract the value from the instruction.  */

      if (operand->extract)

  value = (*operand->extract) (insn, (int *) NULL);

      else

  {

    value = (insn >> operand->shift) & ((1 << operand->bits) - 1);

    if (operand->flags & AXP_OPERAND_SIGNED)

      {

        int signbit = 1 << (operand->bits - 1);

        value = (value ^ signbit) - signbit;

      }

  }

      if (need_comma &&

    ((operand->flags & (AXP_OPERAND_PARENS | AXP_OPERAND_COMMA))

     != AXP_OPERAND_PARENS))

  {

    (*info->fprintf_func) (info->stream, ",");

  }

      if (operand->flags & AXP_OPERAND_PARENS)

  (*info->fprintf_func) (info->stream, "(");

      /* Print the operand as directed by the flags.  */

      if (operand->flags & AXP_OPERAND_IR)

  (*info->fprintf_func) (info->stream, "%s", regnames[value]);

      else if (operand->flags & AXP_OPERAND_FPR)

  (*info->fprintf_func) (info->stream, "%s", regnames[value + 32]);

      else if (operand->flags & AXP_OPERAND_RELATIVE)

  (*info->print_address_func) (memaddr + 4 + value, info);

      else if (operand->flags & AXP_OPERAND_SIGNED)

  (*info->fprintf_func) (info->stream, "%d", value);

      else

  (*info->fprintf_func) (info->stream, "%#x", value);

      if (operand->flags & AXP_OPERAND_PARENS)

  (*info->fprintf_func) (info->stream, ")");

      need_comma = 1;

    }

  return 4;

}