/* mmix-dis.c -- Disassemble MMIX instructions.

   Copyright (C) 2000-2023 Free Software Foundation, Inc.

   Written by Hans-Peter Nilsson (hp@bitrange.com)

   This file is part of the GNU opcodes library.

   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 "opcode/mmix.h"

#include "disassemble.h"

#include "libiberty.h"

#include "bfd.h"

#include "opintl.h"

#define BAD_CASE(x)           \

  do                \

   {               \

     opcodes_error_handler (_("bad case %d (%s) in %s:%d"),  \

          x, #x, __FILE__, __LINE__);   \

     abort ();              \

   }                \

 while (0)

#define FATAL_DEBUG           \

 do                \

   {               \

     opcodes_error_handler (_("internal: non-debugged code " \

            "(test-case missing): %s:%d"),  \

          __FILE__, __LINE__);    \

     abort ();              \

   }                \

 while (0)

#define ROUND_MODE(n)         \

 ((n) == 1 ? "ROUND_OFF" : (n) == 2 ? "ROUND_UP" :  \

  (n) == 3 ? "ROUND_DOWN" : (n) == 4 ? "ROUND_NEAR" :  \

  _("(unknown)"))

#define INSN_IMMEDIATE_BIT (IMM_OFFSET_BIT << 24)

#define INSN_BACKWARD_OFFSET_BIT (1 << 24)

#define MAX_REG_NAME_LEN       256

#define MAX_SPEC_REG_NAME_LEN  32

struct mmix_dis_info

 {

   const char *reg_name[MAX_REG_NAME_LEN];

   const char *spec_reg_name[MAX_SPEC_REG_NAME_LEN];

   /* Waste a little memory so we don't have to allocate each separately.

      We could have an array with static contents for these, but on the

      other hand, we don't have to.  */

   char basic_reg_name[MAX_REG_NAME_LEN][sizeof ("$255")];

 };

/* Initialize a target-specific array in INFO.  */

static bool

initialize_mmix_dis_info (struct disassemble_info *info)

{

  struct mmix_dis_info *minfop = malloc (sizeof (struct mmix_dis_info));

  long i;

  if (minfop == NULL)

    return false;

  memset (minfop, 0, sizeof (*minfop));

  /* Initialize register names from register symbols.  If there's no

     register section, then there are no register symbols.  */

  if ((info->section != NULL && info->section->owner != NULL)

      || (info->symbols != NULL

    && info->symbols[0] != NULL

    && bfd_asymbol_bfd (info->symbols[0]) != NULL))

    {

      bfd *abfd = info->section && info->section->owner != NULL

  ? info->section->owner

  : bfd_asymbol_bfd (info->symbols[0]);

      asection *reg_section = bfd_get_section_by_name (abfd, "*REG*");

      if (reg_section != NULL)

  {

    /* The returned symcount *does* include the ending NULL.  */

    long symsize = bfd_get_symtab_upper_bound (abfd);

    asymbol **syms = malloc (symsize);

    long nsyms;

    if (syms == NULL)

      {

        FATAL_DEBUG;

        free (minfop);

        return false;

      }

    nsyms = bfd_canonicalize_symtab (abfd, syms);

    /* We use the first name for a register.  If this is MMO, then

       it's the name with the first sequence number, presumably the

       first in the source.  */

    for (i = 0; i < nsyms && syms[i] != NULL; i++)

      {

        if (syms[i]->section == reg_section

      && syms[i]->value < MAX_REG_NAME_LEN

      && minfop->reg_name[syms[i]->value] == NULL)

    minfop->reg_name[syms[i]->value] = syms[i]->name;

      }

  }

    }

  /* Fill in the rest with the canonical names.  */

  for (i = 0; i < MAX_REG_NAME_LEN; i++)

    if (minfop->reg_name[i] == NULL)

      {

  sprintf (minfop->basic_reg_name[i], "$%ld", i);

  minfop->reg_name[i] = minfop->basic_reg_name[i];

      }

  /* We assume it's actually a one-to-one mapping of number-to-name.  */

  for (i = 0; mmix_spec_regs[i].name != NULL; i++)

    minfop->spec_reg_name[mmix_spec_regs[i].number] = mmix_spec_regs[i].name;

  info->private_data = (void *) minfop;

  return true;

}

/* A table indexed by the first byte is constructed as we disassemble each

   tetrabyte.  The contents is a pointer into mmix_insns reflecting the

   first found entry with matching match-bits and lose-bits.  Further

   entries are considered one after one until the operand constraints

   match or the match-bits and lose-bits do not match.  Normally a

   "further entry" will just show that there was no other match.  */

static const struct mmix_opcode *

get_opcode (unsigned long insn)

{

  static const struct mmix_opcode **opcodes = NULL;

  const struct mmix_opcode *opcodep = mmix_opcodes;

  unsigned int opcode_part = (insn >> 24) & 255;

  if (opcodes == NULL)

    opcodes = xcalloc (256, sizeof (struct mmix_opcode *));

  opcodep = opcodes[opcode_part];

  if (opcodep == NULL

      || (opcodep->match & insn) != opcodep->match

      || (opcodep->lose & insn) != 0)

    {

      /* Search through the table.  */

      for (opcodep = mmix_opcodes; opcodep->name != NULL; opcodep++)

  {

    /* FIXME: Break out this into an initialization function.  */

    if ((opcodep->match & (opcode_part << 24)) == opcode_part

        && (opcodep->lose & (opcode_part << 24)) == 0)

      opcodes[opcode_part] = opcodep;

    if ((opcodep->match & insn) == opcodep->match

        && (opcodep->lose & insn) == 0)

      break;

  }

    }

  if (opcodep->name == NULL)

    return NULL;

  /* Check constraints.  If they don't match, loop through the next opcode

     entries.  */

  do

    {

      switch (opcodep->operands)

  {

    /* These have no restraint on what can be in the lower three

       bytes.  */

  case mmix_operands_regs:

  case mmix_operands_reg_yz:

  case mmix_operands_regs_z_opt:

  case mmix_operands_regs_z:

  case mmix_operands_jmp:

  case mmix_operands_pushgo:

  case mmix_operands_pop:

  case mmix_operands_sync:

  case mmix_operands_x_regs_z:

  case mmix_operands_neg:

  case mmix_operands_pushj:

  case mmix_operands_regaddr:

  case mmix_operands_get:

  case mmix_operands_set:

  case mmix_operands_save:

  case mmix_operands_unsave:

  case mmix_operands_xyz_opt:

    return opcodep;

    /* For a ROUND_MODE, the middle byte must be 0..4.  */

  case mmix_operands_roundregs_z:

  case mmix_operands_roundregs:

    {

      int midbyte = (insn >> 8) & 255;

      if (midbyte <= 4)

        return opcodep;

    }

  break;

  case mmix_operands_put:

    /* A "PUT".  If it is "immediate", then no restrictions,

       otherwise we have to make sure the register number is < 32.  */

    if ((insn & INSN_IMMEDIATE_BIT)

        || ((insn >> 16) & 255) < 32)

      return opcodep;

    break;

  case mmix_operands_resume:

    /* Middle bytes must be zero.  */

    if ((insn & 0x00ffff00) == 0)

      return opcodep;

    break;

  default:

    BAD_CASE (opcodep->operands);

  }

      opcodep++;

    }

  while ((opcodep->match & insn) == opcodep->match

   && (opcodep->lose & insn) == 0);

  /* If we got here, we had no match.  */

  return NULL;

}

static inline const char *

get_reg_name (const struct mmix_dis_info * minfop, unsigned int x)

{

  if (x >= MAX_REG_NAME_LEN)

    return _("*illegal*");

  return minfop->reg_name[x];

}

static inline const char *

get_spec_reg_name (const struct mmix_dis_info * minfop, unsigned int x)

{

  if (x >= MAX_SPEC_REG_NAME_LEN)

    return _("*illegal*");

  return minfop->spec_reg_name[x];

}

/* The main disassembly function.  */

int

print_insn_mmix (bfd_vma memaddr, struct disassemble_info *info)

{

  unsigned char buffer[4];

  unsigned long insn;

  unsigned int x, y, z;

  const struct mmix_opcode *opcodep;

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

  struct mmix_dis_info *minfop;

  if (status != 0)

    {

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

      return -1;

    }

  /* FIXME: Is -1 suitable?  */

  if (info->private_data == NULL

      && ! initialize_mmix_dis_info (info))

    return -1;

  minfop = (struct mmix_dis_info *) info->private_data;

  x = buffer[1];

  y = buffer[2];

  z = buffer[3];

  insn = bfd_getb32 (buffer);

  opcodep = get_opcode (insn);

  if (opcodep == NULL)

    {

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

      return 4;

    }

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

  /* Present bytes in the order they are laid out in memory.  */

  info->display_endian = BFD_ENDIAN_BIG;

  info->insn_info_valid = 1;

  info->bytes_per_chunk = 4;

  info->branch_delay_insns = 0;

  info->target = 0;

  switch (opcodep->type)

    {

    case mmix_type_normal:

    case mmix_type_memaccess_block:

      info->insn_type = dis_nonbranch;

      break;

    case mmix_type_branch:

      info->insn_type = dis_branch;

      break;

    case mmix_type_condbranch:

      info->insn_type = dis_condbranch;

      break;

    case mmix_type_memaccess_octa:

      info->insn_type = dis_dref;

      info->data_size = 8;

      break;

    case mmix_type_memaccess_tetra:

      info->insn_type = dis_dref;

      info->data_size = 4;

      break;

    case mmix_type_memaccess_wyde:

      info->insn_type = dis_dref;

      info->data_size = 2;

      break;

    case mmix_type_memaccess_byte:

      info->insn_type = dis_dref;

      info->data_size = 1;

      break;

    case mmix_type_jsr:

      info->insn_type = dis_jsr;

      break;

    default:

      BAD_CASE(opcodep->type);

    }

  switch (opcodep->operands)

    {

    case mmix_operands_regs:

      /*  All registers: "$X,$Y,$Z".  */

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

           get_reg_name (minfop, x),

           get_reg_name (minfop, y),

           get_reg_name (minfop, z));

      break;

    case mmix_operands_reg_yz:

      /* Like SETH - "$X,YZ".  */

      (*info->fprintf_func) (info->stream, "%s,0x%x",

           get_reg_name (minfop, x), y * 256 + z);

      break;

    case mmix_operands_regs_z_opt:

    case mmix_operands_regs_z:

    case mmix_operands_pushgo:

      /* The regular "$X,$Y,$Z|Z".  */

      if (insn & INSN_IMMEDIATE_BIT)

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

             get_reg_name (minfop, x),

             get_reg_name (minfop, y), z);

      else

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

             get_reg_name (minfop, x),

             get_reg_name (minfop, y),

             get_reg_name (minfop, z));

      break;

    case mmix_operands_jmp:

      /* Address; only JMP.  */

      {

  bfd_signed_vma offset = (x * 65536 + y * 256 + z) * 4;

  if (insn & INSN_BACKWARD_OFFSET_BIT)

    offset -= (256 * 65536) * 4;

  info->target = memaddr + offset;

  (*info->print_address_func) (memaddr + offset, info);

      }

      break;

    case mmix_operands_roundregs_z:

      /* Two registers, like FLOT, possibly with rounding: "$X,$Z|Z"

   "$X,ROUND_MODE,$Z|Z".  */

      if (y != 0)

  {

    if (insn & INSN_IMMEDIATE_BIT)

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

           get_reg_name (minfop, x),

           ROUND_MODE (y), z);

    else

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

           get_reg_name (minfop, x),

           ROUND_MODE (y),

           get_reg_name (minfop, z));

  }

      else

  {

    if (insn & INSN_IMMEDIATE_BIT)

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

           get_reg_name (minfop, x), z);

    else

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

           get_reg_name (minfop, x),

           get_reg_name (minfop, z));

  }

      break;

    case mmix_operands_pop:

      /* Like POP - "X,YZ".  */

      (*info->fprintf_func) (info->stream, "%d,%d", x, y*256 + z);

      break;

    case mmix_operands_roundregs:

      /* Two registers, possibly with rounding: "$X,$Z" or

   "$X,ROUND_MODE,$Z".  */

      if (y != 0)

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

             get_reg_name (minfop, x),

             ROUND_MODE (y),

             get_reg_name (minfop, z));

      else

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

             get_reg_name (minfop, x),

             get_reg_name (minfop, z));

      break;

    case mmix_operands_sync:

  /* Like SYNC - "XYZ".  */

      (*info->fprintf_func) (info->stream, "%u",

           x * 65536 + y * 256 + z);

      break;

    case mmix_operands_x_regs_z:

      /* Like SYNCD - "X,$Y,$Z|Z".  */

      if (insn & INSN_IMMEDIATE_BIT)

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

             x, get_reg_name (minfop, y), z);

      else

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

             x, get_reg_name (minfop, y),

             get_reg_name (minfop, z));

      break;

    case mmix_operands_neg:

      /* Like NEG and NEGU - "$X,Y,$Z|Z".  */

      if (insn & INSN_IMMEDIATE_BIT)

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

             get_reg_name (minfop, x), y, z);

      else

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

             get_reg_name (minfop, x), y,

             get_reg_name (minfop, z));

      break;

    case mmix_operands_pushj:

    case mmix_operands_regaddr:

      /* Like GETA or branches - "$X,Address".  */

      {

  bfd_signed_vma offset = (y * 256 + z) * 4;

  if (insn & INSN_BACKWARD_OFFSET_BIT)

    offset -= 65536 * 4;

  info->target = memaddr + offset;

  (*info->fprintf_func) (info->stream, "%s,", get_reg_name (minfop, x));

  (*info->print_address_func) (memaddr + offset, info);

      }

      break;

    case mmix_operands_get:

      /* GET - "X,spec_reg".  */

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

           get_reg_name (minfop, x),

           get_spec_reg_name (minfop, z));

      break;

    case mmix_operands_put:

      /* PUT - "spec_reg,$Z|Z".  */

      if (insn & INSN_IMMEDIATE_BIT)

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

             get_spec_reg_name (minfop, x), z);

      else

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

             get_spec_reg_name (minfop, x),

             get_reg_name (minfop, z));

      break;

    case mmix_operands_set:

      /*  Two registers, "$X,$Y".  */

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

           get_reg_name (minfop, x),

           get_reg_name (minfop, y));

      break;

    case mmix_operands_save:

      /* SAVE - "$X,0".  */

      (*info->fprintf_func) (info->stream, "%s,0", minfop->reg_name[x]);

      break;

    case mmix_operands_unsave:

      /* UNSAVE - "0,$Z".  */

      (*info->fprintf_func) (info->stream, "0,%s", minfop->reg_name[z]);

      break;

    case mmix_operands_xyz_opt:

      /* Like SWYM or TRAP - "X,Y,Z".  */

      (*info->fprintf_func) (info->stream, "%d,%d,%d", x, y, z);

      break;

    case mmix_operands_resume:

      /* Just "Z", like RESUME.  */

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

      break;

    default:

      (*info->fprintf_func) (info->stream, _("*unknown operands type: %d*"),

           opcodep->operands);

      break;

    }

  return 4;

}