// SPDX-License-Identifier: GPL-2.0-or-later
/* ppc-dis.c -- Disassemble PowerPC instructions
   Copyright (C) 1994-2016 Free Software Foundation, Inc.
   Written by Ian Lance Taylor, Cygnus Support

This file is part of GDB, GAS, and the GNU binutils.

 */

#include <asm/cputable.h>
#include <asm/cpu_has_feature.h>
#include "nonstdio.h"
#include "ansidecl.h"
#include "ppc.h"
#include "dis-asm.h"

/* This file provides several disassembler functions, all of which use
   the disassembler interface defined in dis-asm.h.  Several functions
   are provided because this file handles disassembly for the PowerPC
   in both big and little endian mode and also for the POWER (RS/6000)
   chip.  */

/* Extract the operand value from the PowerPC or POWER instruction.  */

static long
operand_value_powerpc (const struct powerpc_operand *operand,
                       unsigned long insn, ppc_cpu_t dialect)
{
  long value;
  int invalid;
  /* Extract the value from the instruction.  */
  if (operand->extract)
    value = (*operand->extract) (insn, dialect, &invalid);
  else
    {
      if (operand->shift >= 0)
        value = (insn >> operand->shift) & operand->bitm;
      else
        value = (insn << -operand->shift) & operand->bitm;
      if ((operand->flags & PPC_OPERAND_SIGNED) != 0)
        {
          /* BITM is always some number of zeros followed by some
             number of ones, followed by some number of zeros.  */
          unsigned long top = operand->bitm;
          /* top & -top gives the rightmost 1 bit, so this
             fills in any trailing zeros.  */
          top |= (top & -top) - 1;
          top &= ~(top >> 1);
          value = (value ^ top) - top;
        }
    }

  return value;
}

/* Determine whether the optional operand(s) should be printed.  */

static int
skip_optional_operands (const unsigned char *opindex,
                        unsigned long insn, ppc_cpu_t dialect)
{
  const struct powerpc_operand *operand;

  for (; *opindex != 0; opindex++)
    {
      operand = &powerpc_operands[*opindex];
      if ((operand->flags & PPC_OPERAND_NEXT) != 0
          || ((operand->flags & PPC_OPERAND_OPTIONAL) != 0
              && operand_value_powerpc (operand, insn, dialect) !=
                 ppc_optional_operand_value (operand)))
        return 0;
    }

  return 1;
}

/* Find a match for INSN in the opcode table, given machine DIALECT.
   A DIALECT of -1 is special, matching all machine opcode variations.  */

static const struct powerpc_opcode *
lookup_powerpc (unsigned long insn, ppc_cpu_t dialect)
{
  const struct powerpc_opcode *opcode;
  const struct powerpc_opcode *opcode_end;

  opcode_end = powerpc_opcodes + powerpc_num_opcodes;
  /* Find the first match in the opcode table for this major opcode.  */
  for (opcode = powerpc_opcodes; opcode < opcode_end; ++opcode)
    {
      const unsigned char *opindex;
      const struct powerpc_operand *operand;
      int invalid;

      if ((insn & opcode->mask) != opcode->opcode
          || (dialect != (ppc_cpu_t) -1
              && ((opcode->flags & dialect) == 0
                  || (opcode->deprecated & dialect) != 0)))
        continue;

      /* Check validity of operands.  */
      invalid = 0;
      for (opindex = opcode->operands; *opindex != 0; opindex++)
        {
          operand = powerpc_operands + *opindex;
          if (operand->extract)
            (*operand->extract) (insn, dialect, &invalid);
        }
      if (invalid)
        continue;

      return opcode;
    }

  return NULL;
}

/* Print a PowerPC or POWER instruction.  */

int print_insn_powerpc (unsigned long insn, unsigned long memaddr)
{
  const struct powerpc_opcode *opcode;
  bool insn_is_short;
  ppc_cpu_t dialect;

  dialect = PPC_OPCODE_PPC | PPC_OPCODE_COMMON;

  if (IS_ENABLED(CONFIG_PPC64))
    dialect |= PPC_OPCODE_64 | PPC_OPCODE_POWER4 | PPC_OPCODE_CELL |
        PPC_OPCODE_POWER5 | PPC_OPCODE_POWER6 | PPC_OPCODE_POWER7 | PPC_OPCODE_POWER8 |
        PPC_OPCODE_POWER9;

  if (cpu_has_feature(CPU_FTR_TM))
    dialect |= PPC_OPCODE_HTM;

  if (cpu_has_feature(CPU_FTR_ALTIVEC))
    dialect |= PPC_OPCODE_ALTIVEC | PPC_OPCODE_ALTIVEC2;

  if (cpu_has_feature(CPU_FTR_VSX))
    dialect |= PPC_OPCODE_VSX | PPC_OPCODE_VSX3;

  /* Get the major opcode of the insn.  */
  opcode = NULL;
  insn_is_short = false;

  if (opcode == NULL)
    opcode = lookup_powerpc (insn, dialect);
  if (opcode == NULL && (dialect & PPC_OPCODE_ANY) != 0)
    opcode = lookup_powerpc (insn, (ppc_cpu_t) -1);

  if (opcode != NULL)
    {
      const unsigned char *opindex;
      const struct powerpc_operand *operand;
      int need_comma;
      int need_paren;
      int skip_optional;

      if (opcode->operands[0] != 0)
        printf("%-7s ", opcode->name);
      else
        printf("%s", opcode->name);

      if (insn_is_short)
        /* The operands will be fetched out of the 16-bit instruction.  */
        insn >>= 16;

      /* Now extract and print the operands.  */
      need_comma = 0;
      need_paren = 0;
      skip_optional = -1;
      for (opindex = opcode->operands; *opindex != 0; opindex++)
        {
          long value;

          operand = powerpc_operands + *opindex;

          /* 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 & PPC_OPERAND_FAKE) != 0)
            continue;

          /* If all of the optional operands have the value zero,
             then don't print any of them.  */
          if ((operand->flags & PPC_OPERAND_OPTIONAL) != 0)
            {
              if (skip_optional < 0)
                skip_optional = skip_optional_operands (opindex, insn,
                                                        dialect);
              if (skip_optional)
                continue;
            }

          value = operand_value_powerpc (operand, insn, dialect);

          if (need_comma)
            {
              printf(",");
              need_comma = 0;
            }

          /* Print the operand as directed by the flags.  */
          if ((operand->flags & PPC_OPERAND_GPR) != 0
              || ((operand->flags & PPC_OPERAND_GPR_0) != 0 && value != 0))
            printf("r%ld", value);
          else if ((operand->flags & PPC_OPERAND_FPR) != 0)
            printf("f%ld", value);
          else if ((operand->flags & PPC_OPERAND_VR) != 0)
            printf("v%ld", value);
          else if ((operand->flags & PPC_OPERAND_VSR) != 0)
            printf("vs%ld", value);
          else if ((operand->flags & PPC_OPERAND_RELATIVE) != 0)
            print_address(memaddr + value);
          else if ((operand->flags & PPC_OPERAND_ABSOLUTE) != 0)
            print_address(value & 0xffffffff);
          else if ((operand->flags & PPC_OPERAND_FSL) != 0)
            printf("fsl%ld", value);
          else if ((operand->flags & PPC_OPERAND_FCR) != 0)
            printf("fcr%ld", value);
          else if ((operand->flags & PPC_OPERAND_UDI) != 0)
            printf("%ld", value);
          else if ((operand->flags & PPC_OPERAND_CR_REG) != 0
                   && (((dialect & PPC_OPCODE_PPC) != 0)
                       || ((dialect & PPC_OPCODE_VLE) != 0)))
            printf("cr%ld", value);
          else if (((operand->flags & PPC_OPERAND_CR_BIT) != 0)
                   && (((dialect & PPC_OPCODE_PPC) != 0)
                       || ((dialect & PPC_OPCODE_VLE) != 0)))
            {
              static const char *cbnames[4] = { "lt", "gt", "eq", "so" };
              int cr;
              int cc;

              cr = value >> 2;
              if (cr != 0)
                printf("4*cr%d+", cr);
              cc = value & 3;
              printf("%s", cbnames[cc]);
            }
          else
            printf("%d", (int) value);

          if (need_paren)
            {
              printf(")");
              need_paren = 0;
            }

          if ((operand->flags & PPC_OPERAND_PARENS) == 0)
            need_comma = 1;
          else
            {
              printf("(");
              need_paren = 1;
            }
        }

      /* We have found and printed an instruction.
         If it was a short VLE instruction we have more to do.  */
      if (insn_is_short)
        {
          memaddr += 2;
          return 2;
        }
      else
        /* Otherwise, return.  */
        return 4;
    }

  /* We could not find a match.  */
  printf(".long 0x%lx", insn);

  return 4;
}