/* alpha-dis.c -- Disassemble Alpha AXP instructions
  Copyright (C) 1996-2024 Free Software Foundation, Inc.
  Contributed by Richard Henderson <[email protected]>,
  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;
}