Subversion Repositories openrisc_2011-10-31

/* Target-dependent code for the Toshiba MeP for GDB, the GNU debugger.

   Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010

   Free Software Foundation, Inc.

   Contributed by Red Hat, Inc.

   This file is part of GDB.

   This program 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 of the License, or

   (at your option) any later version.

   This program 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 program.  If not, see <http://www.gnu.org/licenses/>.  */

#include "defs.h"

#include "frame.h"

#include "frame-unwind.h"

#include "frame-base.h"

#include "symtab.h"

#include "gdbtypes.h"

#include "gdbcmd.h"

#include "gdbcore.h"

#include "gdb_string.h"

#include "value.h"

#include "inferior.h"

#include "dis-asm.h"

#include "symfile.h"

#include "objfiles.h"

#include "language.h"

#include "arch-utils.h"

#include "regcache.h"

#include "remote.h"

#include "floatformat.h"

#include "sim-regno.h"

#include "disasm.h"

#include "trad-frame.h"

#include "reggroups.h"

#include "elf-bfd.h"

#include "elf/mep.h"

#include "prologue-value.h"

#include "cgen/bitset.h"

#include "infcall.h"

#include "gdb_assert.h"

/* Get the user's customized MeP coprocessor register names from

   libopcodes.  */

#include "opcodes/mep-desc.h"

#include "opcodes/mep-opc.h"

/* The gdbarch_tdep structure.  */

/* A quick recap for GDB hackers not familiar with the whole Toshiba

   Media Processor story:

   The MeP media engine is a configureable processor: users can design

   their own coprocessors, implement custom instructions, adjust cache

   sizes, select optional standard facilities like add-and-saturate

   instructions, and so on.  Then, they can build custom versions of

   the GNU toolchain to support their customized chips.  The

   MeP-Integrator program (see utils/mep) takes a GNU toolchain source

   tree, and a config file pointing to various files provided by the

   user describing their customizations, and edits the source tree to

   produce a compiler that can generate their custom instructions, an

   assembler that can assemble them and recognize their custom

   register names, and so on.

   Furthermore, the user can actually specify several of these custom

   configurations, called 'me_modules', and get a toolchain which can

   produce code for any of them, given a compiler/assembler switch;

   you say something like 'gcc -mconfig=mm_max' to generate code for

   the me_module named 'mm_max'.

   GDB, in particular, needs to:

   - use the coprocessor control register names provided by the user

     in their hardware description, in expressions, 'info register'

     output, and disassembly,

   - know the number, names, and types of the coprocessor's

     general-purpose registers, adjust the 'info all-registers' output

     accordingly, and print error messages if the user refers to one

     that doesn't exist

   - allow access to the control bus space only when the configuration

     actually has a control bus, and recognize which regions of the

     control bus space are actually populated,

   - disassemble using the user's provided mnemonics for their custom

     instructions, and

   - recognize whether the $hi and $lo registers are present, and

     allow access to them only when they are actually there.

   There are three sources of information about what sort of me_module

   we're actually dealing with:

   - A MeP executable file indicates which me_module it was compiled

     for, and libopcodes has tables describing each module.  So, given

     an executable file, we can find out about the processor it was

     compiled for.

   - There are SID command-line options to select a particular

     me_module, overriding the one specified in the ELF file.  SID

     provides GDB with a fake read-only register, 'module', which

     indicates which me_module GDB is communicating with an instance

     of.

   - There are SID command-line options to enable or disable certain

     optional processor features, overriding the defaults for the

     selected me_module.  The MeP $OPT register indicates which

     options are present on the current processor.  */

struct gdbarch_tdep

{

  /* A CGEN cpu descriptor for this BFD architecture and machine.

     Note: this is *not* customized for any particular me_module; the

     MeP libopcodes machinery actually puts off module-specific

     customization until the last minute.  So this contains

     information about all supported me_modules.  */

  CGEN_CPU_DESC cpu_desc;

  /* The me_module index from the ELF file we used to select this

     architecture, or CONFIG_NONE if there was none.

     Note that we should prefer to use the me_module number available

     via the 'module' register, whenever we're actually talking to a

     real target.

     In the absence of live information, we'd like to get the

     me_module number from the ELF file.  But which ELF file: the

     executable file, the core file, ... ?  The answer is, "the last

     ELF file we used to set the current architecture".  Thus, we

     create a separate instance of the gdbarch structure for each

     me_module value mep_gdbarch_init sees, and store the me_module

     value from the ELF file here.  */

  CONFIG_ATTR me_module;

};

/* Getting me_module information from the CGEN tables.  */

/* Find an entry in the DESC's hardware table whose name begins with

   PREFIX, and whose ISA mask intersects COPRO_ISA_MASK, but does not

   intersect with GENERIC_ISA_MASK.  If there is no matching entry,

   return zero.  */

static const CGEN_HW_ENTRY *

find_hw_entry_by_prefix_and_isa (CGEN_CPU_DESC desc,

                                 const char *prefix,

                                 CGEN_BITSET *copro_isa_mask,

                                 CGEN_BITSET *generic_isa_mask)

{

  int prefix_len = strlen (prefix);

  int i;

  for (i = 0; i < desc->hw_table.num_entries; i++)

    {

      const CGEN_HW_ENTRY *hw = desc->hw_table.entries[i];

      if (strncmp (prefix, hw->name, prefix_len) == 0)

        {

          CGEN_BITSET *hw_isa_mask

            = ((CGEN_BITSET *)

               &CGEN_ATTR_CGEN_HW_ISA_VALUE (CGEN_HW_ATTRS (hw)));

          if (cgen_bitset_intersect_p (hw_isa_mask, copro_isa_mask)

              && ! cgen_bitset_intersect_p (hw_isa_mask, generic_isa_mask))

            return hw;

        }

    }

  return 0;

}

/* Find an entry in DESC's hardware table whose type is TYPE.  Return

   zero if there is none.  */

static const CGEN_HW_ENTRY *

find_hw_entry_by_type (CGEN_CPU_DESC desc, CGEN_HW_TYPE type)

{

  int i;

  for (i = 0; i < desc->hw_table.num_entries; i++)

    {

      const CGEN_HW_ENTRY *hw = desc->hw_table.entries[i];

      if (hw->type == type)

        return hw;

    }

  return 0;

}

/* Return the CGEN hardware table entry for the coprocessor register

   set for ME_MODULE, whose name prefix is PREFIX.  If ME_MODULE has

   no such register set, return zero.  If ME_MODULE is the generic

   me_module CONFIG_NONE, return the table entry for the register set

   whose hardware type is GENERIC_TYPE.  */

static const CGEN_HW_ENTRY *

me_module_register_set (CONFIG_ATTR me_module,

                        const char *prefix,

                        CGEN_HW_TYPE generic_type)

{

  /* This is kind of tricky, because the hardware table is constructed

     in a way that isn't very helpful.  Perhaps we can fix that, but

     here's how it works at the moment:

     The configuration map, `mep_config_map', is indexed by me_module

     number, and indicates which coprocessor and core ISAs that

     me_module supports.  The 'core_isa' mask includes all the core

     ISAs, and the 'cop_isa' mask includes all the coprocessor ISAs.

     The entry for the generic me_module, CONFIG_NONE, has an empty

     'cop_isa', and its 'core_isa' selects only the standard MeP

     instruction set.

     The CGEN CPU descriptor's hardware table, desc->hw_table, has

     entries for all the register sets, for all me_modules.  Each

     entry has a mask indicating which ISAs use that register set.

     So, if an me_module supports some coprocessor ISA, we can find

     applicable register sets by scanning the hardware table for

     register sets whose masks include (at least some of) those ISAs.

     Each hardware table entry also has a name, whose prefix says

     whether it's a general-purpose ("h-cr") or control ("h-ccr")

     coprocessor register set.  It might be nicer to have an attribute

     indicating what sort of register set it was, that we could use

     instead of pattern-matching on the name.

     When there is no hardware table entry whose mask includes a

     particular coprocessor ISA and whose name starts with a given

     prefix, then that means that that coprocessor doesn't have any

     registers of that type.  In such cases, this function must return

     a null pointer.

     Coprocessor register sets' masks may or may not include the core

     ISA for the me_module they belong to.  Those generated by a2cgen

     do, but the sample me_module included in the unconfigured tree,

     'ccfx', does not.

     There are generic coprocessor register sets, intended only for

     use with the generic me_module.  Unfortunately, their masks

     include *all* ISAs --- even those for coprocessors that don't

     have such register sets.  This makes detecting the case where a

     coprocessor lacks a particular register set more complicated.

     So, here's the approach we take:

     - For CONFIG_NONE, we return the generic coprocessor register set.

     - For any other me_module, we search for a register set whose

       mask contains any of the me_module's coprocessor ISAs,

       specifically excluding the generic coprocessor register sets.  */

  CGEN_CPU_DESC desc = gdbarch_tdep (target_gdbarch)->cpu_desc;

  const CGEN_HW_ENTRY *hw;

  if (me_module == CONFIG_NONE)

    hw = find_hw_entry_by_type (desc, generic_type);

  else

    {

      CGEN_BITSET *cop = &mep_config_map[me_module].cop_isa;

      CGEN_BITSET *core = &mep_config_map[me_module].core_isa;

      CGEN_BITSET *generic = &mep_config_map[CONFIG_NONE].core_isa;

      CGEN_BITSET *cop_and_core;

      /* The coprocessor ISAs include the ISA for the specific core which

         has that coprocessor.  */

      cop_and_core = cgen_bitset_copy (cop);

      cgen_bitset_union (cop, core, cop_and_core);

      hw = find_hw_entry_by_prefix_and_isa (desc, prefix, cop_and_core, generic);

    }

  return hw;

}

/* Given a hardware table entry HW representing a register set, return

   a pointer to the keyword table with all the register names.  If HW

   is NULL, return NULL, to propage the "no such register set" info

   along.  */

static CGEN_KEYWORD *

register_set_keyword_table (const CGEN_HW_ENTRY *hw)

{

  if (! hw)

    return NULL;

  /* Check that HW is actually a keyword table.  */

  gdb_assert (hw->asm_type == CGEN_ASM_KEYWORD);

  /* The 'asm_data' field of a register set's hardware table entry

     refers to a keyword table.  */

  return (CGEN_KEYWORD *) hw->asm_data;

}

/* Given a keyword table KEYWORD and a register number REGNUM, return

   the name of the register, or "" if KEYWORD contains no register

   whose number is REGNUM.  */

static char *

register_name_from_keyword (CGEN_KEYWORD *keyword_table, int regnum)

{

  const CGEN_KEYWORD_ENTRY *entry

    = cgen_keyword_lookup_value (keyword_table, regnum);

  if (entry)

    {

      char *name = entry->name;

      /* The CGEN keyword entries for register names include the

         leading $, which appears in MeP assembly as well as in GDB.

         But we don't want to return that; GDB core code adds that

         itself.  */

      if (name[0] == '$')

        name++;

      return name;

    }

  else

    return "";

}

/* Masks for option bits in the OPT special-purpose register.  */

enum {

  MEP_OPT_DIV = 1 << 25,        /* 32-bit divide instruction option */

  MEP_OPT_MUL = 1 << 24,        /* 32-bit multiply instruction option */

  MEP_OPT_BIT = 1 << 23,        /* bit manipulation instruction option */

  MEP_OPT_SAT = 1 << 22,        /* saturation instruction option */

  MEP_OPT_CLP = 1 << 21,        /* clip instruction option */

  MEP_OPT_MIN = 1 << 20,        /* min/max instruction option */

  MEP_OPT_AVE = 1 << 19,        /* average instruction option */

  MEP_OPT_ABS = 1 << 18,        /* absolute difference instruction option */

  MEP_OPT_LDZ = 1 << 16,        /* leading zero instruction option */

  MEP_OPT_VL64 = 1 << 6,        /* 64-bit VLIW operation mode option */

  MEP_OPT_VL32 = 1 << 5,        /* 32-bit VLIW operation mode option */

  MEP_OPT_COP = 1 << 4,         /* coprocessor option */

  MEP_OPT_DSP = 1 << 2,         /* DSP option */

  MEP_OPT_UCI = 1 << 1,         /* UCI option */

  MEP_OPT_DBG = 1 << 0,         /* DBG function option */

};

/* Given the option_mask value for a particular entry in

   mep_config_map, produce the value the processor's OPT register

   would use to represent the same set of options.  */

static unsigned int

opt_from_option_mask (unsigned int option_mask)

{

  /* A table mapping OPT register bits onto CGEN config map option

     bits.  */

  struct {

    unsigned int opt_bit, option_mask_bit;

  } bits[] = {

    { MEP_OPT_DIV, 1 << CGEN_INSN_OPTIONAL_DIV_INSN },

    { MEP_OPT_MUL, 1 << CGEN_INSN_OPTIONAL_MUL_INSN },

    { MEP_OPT_DIV, 1 << CGEN_INSN_OPTIONAL_DIV_INSN },

    { MEP_OPT_DBG, 1 << CGEN_INSN_OPTIONAL_DEBUG_INSN },

    { MEP_OPT_LDZ, 1 << CGEN_INSN_OPTIONAL_LDZ_INSN },

    { MEP_OPT_ABS, 1 << CGEN_INSN_OPTIONAL_ABS_INSN },

    { MEP_OPT_AVE, 1 << CGEN_INSN_OPTIONAL_AVE_INSN },

    { MEP_OPT_MIN, 1 << CGEN_INSN_OPTIONAL_MINMAX_INSN },

    { MEP_OPT_CLP, 1 << CGEN_INSN_OPTIONAL_CLIP_INSN },

    { MEP_OPT_SAT, 1 << CGEN_INSN_OPTIONAL_SAT_INSN },

    { MEP_OPT_UCI, 1 << CGEN_INSN_OPTIONAL_UCI_INSN },

    { MEP_OPT_DSP, 1 << CGEN_INSN_OPTIONAL_DSP_INSN },

    { MEP_OPT_COP, 1 << CGEN_INSN_OPTIONAL_CP_INSN },

  };

  int i;

  unsigned int opt = 0;

  for (i = 0; i < (sizeof (bits) / sizeof (bits[0])); i++)

    if (option_mask & bits[i].option_mask_bit)

      opt |= bits[i].opt_bit;

  return opt;

}

/* Return the value the $OPT register would use to represent the set

   of options for ME_MODULE.  */

static unsigned int

me_module_opt (CONFIG_ATTR me_module)

{

  return opt_from_option_mask (mep_config_map[me_module].option_mask);

}

/* Return the width of ME_MODULE's coprocessor data bus, in bits.

   This is either 32 or 64.  */

static int

me_module_cop_data_bus_width (CONFIG_ATTR me_module)

{

  if (mep_config_map[me_module].option_mask

      & (1 << CGEN_INSN_OPTIONAL_CP64_INSN))

    return 64;

  else

    return 32;

}

/* Return true if ME_MODULE is big-endian, false otherwise.  */

static int

me_module_big_endian (CONFIG_ATTR me_module)

{

  return mep_config_map[me_module].big_endian;

}

/* Return the name of ME_MODULE, or NULL if it has no name.  */

static const char *

me_module_name (CONFIG_ATTR me_module)

{

  /* The default me_module has "" as its name, but it's easier for our

     callers to test for NULL.  */

  if (! mep_config_map[me_module].name

      || mep_config_map[me_module].name[0] == '\0')

    return NULL;

  else

    return mep_config_map[me_module].name;

}

/* Register set.  */

/* The MeP spec defines the following registers:

   16 general purpose registers (r0-r15)

   32 control/special registers (csr0-csr31)

   32 coprocessor general-purpose registers (c0 -- c31)

   64 coprocessor control registers (ccr0 -- ccr63)

   For the raw registers, we assign numbers here explicitly, instead

   of letting the enum assign them for us; the numbers are a matter of

   external protocol, and shouldn't shift around as things are edited.

   We access the control/special registers via pseudoregisters, to

   enforce read-only portions that some registers have.

   We access the coprocessor general purpose and control registers via

   pseudoregisters, to make sure they appear in the proper order in

   the 'info all-registers' command (which uses the register number

   ordering), and also to allow them to be renamed and resized

   depending on the me_module in use.

   The MeP allows coprocessor general-purpose registers to be either

   32 or 64 bits long, depending on the configuration.  Since we don't

   want the format of the 'g' packet to vary from one core to another,

   the raw coprocessor GPRs are always 64 bits.  GDB doesn't allow the

   types of registers to change (see the implementation of

   register_type), so we have four banks of pseudoregisters for the

   coprocessor gprs --- 32-bit vs. 64-bit, and integer

   vs. floating-point --- and we show or hide them depending on the

   configuration.  */

enum

{

  MEP_FIRST_RAW_REGNUM = 0,

  MEP_FIRST_GPR_REGNUM = 0,

  MEP_R0_REGNUM = 0,

  MEP_R1_REGNUM = 1,

  MEP_R2_REGNUM = 2,

  MEP_R3_REGNUM = 3,

  MEP_R4_REGNUM = 4,

  MEP_R5_REGNUM = 5,

  MEP_R6_REGNUM = 6,

  MEP_R7_REGNUM = 7,

  MEP_R8_REGNUM = 8,

  MEP_R9_REGNUM = 9,

  MEP_R10_REGNUM = 10,

  MEP_R11_REGNUM = 11,

  MEP_R12_REGNUM = 12,

  MEP_FP_REGNUM = MEP_R8_REGNUM,

  MEP_R13_REGNUM = 13,

  MEP_TP_REGNUM = MEP_R13_REGNUM,       /* (r13) Tiny data pointer */

  MEP_R14_REGNUM = 14,

  MEP_GP_REGNUM = MEP_R14_REGNUM,       /* (r14) Global pointer */

  MEP_R15_REGNUM = 15,

  MEP_SP_REGNUM = MEP_R15_REGNUM,       /* (r15) Stack pointer */

  MEP_LAST_GPR_REGNUM = MEP_R15_REGNUM,

  /* The raw control registers.  These are the values as received via

     the remote protocol, directly from the target; we only let user

     code touch the via the pseudoregisters, which enforce read-only

     bits.  */

  MEP_FIRST_RAW_CSR_REGNUM = 16,

  MEP_RAW_PC_REGNUM    = 16,    /* Program counter */

  MEP_RAW_LP_REGNUM    = 17,    /* Link pointer */

  MEP_RAW_SAR_REGNUM   = 18,    /* Raw shift amount */

  MEP_RAW_CSR3_REGNUM  = 19,    /* csr3: reserved */

  MEP_RAW_RPB_REGNUM   = 20,    /* Raw repeat begin address */

  MEP_RAW_RPE_REGNUM   = 21,    /* Repeat end address */

  MEP_RAW_RPC_REGNUM   = 22,    /* Repeat count */

  MEP_RAW_HI_REGNUM    = 23, /* Upper 32 bits of result of 64 bit mult/div */

  MEP_RAW_LO_REGNUM    = 24, /* Lower 32 bits of result of 64 bit mult/div */

  MEP_RAW_CSR9_REGNUM  = 25,    /* csr3: reserved */

  MEP_RAW_CSR10_REGNUM = 26,    /* csr3: reserved */

  MEP_RAW_CSR11_REGNUM = 27,    /* csr3: reserved */

  MEP_RAW_MB0_REGNUM   = 28,    /* Raw modulo begin address 0 */

  MEP_RAW_ME0_REGNUM   = 29,    /* Raw modulo end address 0 */

  MEP_RAW_MB1_REGNUM   = 30,    /* Raw modulo begin address 1 */

  MEP_RAW_ME1_REGNUM   = 31,    /* Raw modulo end address 1 */

  MEP_RAW_PSW_REGNUM   = 32,    /* Raw program status word */

  MEP_RAW_ID_REGNUM    = 33,    /* Raw processor ID/revision */

  MEP_RAW_TMP_REGNUM   = 34,    /* Temporary */

  MEP_RAW_EPC_REGNUM   = 35,    /* Exception program counter */

  MEP_RAW_EXC_REGNUM   = 36,    /* Raw exception cause */

  MEP_RAW_CFG_REGNUM   = 37,    /* Raw processor configuration*/

  MEP_RAW_CSR22_REGNUM = 38,    /* csr3: reserved */

  MEP_RAW_NPC_REGNUM   = 39,    /* Nonmaskable interrupt PC */

  MEP_RAW_DBG_REGNUM   = 40,    /* Raw debug */

  MEP_RAW_DEPC_REGNUM  = 41,    /* Debug exception PC */

  MEP_RAW_OPT_REGNUM   = 42,    /* Raw options */

  MEP_RAW_RCFG_REGNUM  = 43,    /* Raw local ram config */

  MEP_RAW_CCFG_REGNUM  = 44,    /* Raw cache config */

  MEP_RAW_CSR29_REGNUM = 45,    /* csr3: reserved */

  MEP_RAW_CSR30_REGNUM = 46,    /* csr3: reserved */

  MEP_RAW_CSR31_REGNUM = 47,    /* csr3: reserved */

  MEP_LAST_RAW_CSR_REGNUM = MEP_RAW_CSR31_REGNUM,

  /* The raw coprocessor general-purpose registers.  These are all 64

     bits wide.  */

  MEP_FIRST_RAW_CR_REGNUM = 48,

  MEP_LAST_RAW_CR_REGNUM = MEP_FIRST_RAW_CR_REGNUM + 31,

  MEP_FIRST_RAW_CCR_REGNUM = 80,

  MEP_LAST_RAW_CCR_REGNUM = MEP_FIRST_RAW_CCR_REGNUM + 63,

  /* The module number register.  This is the index of the me_module

     of which the current target is an instance.  (This is not a real

     MeP-specified register; it's provided by SID.)  */

  MEP_MODULE_REGNUM,

  MEP_LAST_RAW_REGNUM = MEP_MODULE_REGNUM,

  MEP_NUM_RAW_REGS = MEP_LAST_RAW_REGNUM + 1,

  /* Pseudoregisters.  See mep_pseudo_register_read and

     mep_pseudo_register_write.  */

  MEP_FIRST_PSEUDO_REGNUM = MEP_NUM_RAW_REGS,

  /* We have a pseudoregister for every control/special register, to

     implement registers with read-only bits.  */

  MEP_FIRST_CSR_REGNUM = MEP_FIRST_PSEUDO_REGNUM,

  MEP_PC_REGNUM = MEP_FIRST_CSR_REGNUM, /* Program counter */

  MEP_LP_REGNUM,                /* Link pointer */

  MEP_SAR_REGNUM,               /* shift amount */

  MEP_CSR3_REGNUM,              /* csr3: reserved */

  MEP_RPB_REGNUM,               /* repeat begin address */

  MEP_RPE_REGNUM,               /* Repeat end address */

  MEP_RPC_REGNUM,               /* Repeat count */

  MEP_HI_REGNUM,  /* Upper 32 bits of the result of 64 bit mult/div */

  MEP_LO_REGNUM,  /* Lower 32 bits of the result of 64 bit mult/div */

  MEP_CSR9_REGNUM,              /* csr3: reserved */

  MEP_CSR10_REGNUM,             /* csr3: reserved */

  MEP_CSR11_REGNUM,             /* csr3: reserved */

  MEP_MB0_REGNUM,               /* modulo begin address 0 */

  MEP_ME0_REGNUM,               /* modulo end address 0 */

  MEP_MB1_REGNUM,               /* modulo begin address 1 */

  MEP_ME1_REGNUM,               /* modulo end address 1 */

  MEP_PSW_REGNUM,               /* program status word */

  MEP_ID_REGNUM,                /* processor ID/revision */

  MEP_TMP_REGNUM,               /* Temporary */

  MEP_EPC_REGNUM,               /* Exception program counter */

  MEP_EXC_REGNUM,               /* exception cause */

  MEP_CFG_REGNUM,               /* processor configuration*/

  MEP_CSR22_REGNUM,             /* csr3: reserved */

  MEP_NPC_REGNUM,               /* Nonmaskable interrupt PC */

  MEP_DBG_REGNUM,               /* debug */

  MEP_DEPC_REGNUM,              /* Debug exception PC */

  MEP_OPT_REGNUM,               /* options */

  MEP_RCFG_REGNUM,              /* local ram config */

  MEP_CCFG_REGNUM,              /* cache config */

  MEP_CSR29_REGNUM,             /* csr3: reserved */

  MEP_CSR30_REGNUM,             /* csr3: reserved */

  MEP_CSR31_REGNUM,             /* csr3: reserved */

  MEP_LAST_CSR_REGNUM = MEP_CSR31_REGNUM,

  /* The 32-bit integer view of the coprocessor GPR's.  */

  MEP_FIRST_CR32_REGNUM,

  MEP_LAST_CR32_REGNUM = MEP_FIRST_CR32_REGNUM + 31,

  /* The 32-bit floating-point view of the coprocessor GPR's.  */

  MEP_FIRST_FP_CR32_REGNUM,

  MEP_LAST_FP_CR32_REGNUM = MEP_FIRST_FP_CR32_REGNUM + 31,

  /* The 64-bit integer view of the coprocessor GPR's.  */

  MEP_FIRST_CR64_REGNUM,

  MEP_LAST_CR64_REGNUM = MEP_FIRST_CR64_REGNUM + 31,

  /* The 64-bit floating-point view of the coprocessor GPR's.  */

  MEP_FIRST_FP_CR64_REGNUM,

  MEP_LAST_FP_CR64_REGNUM = MEP_FIRST_FP_CR64_REGNUM + 31,

  MEP_FIRST_CCR_REGNUM,

  MEP_LAST_CCR_REGNUM = MEP_FIRST_CCR_REGNUM + 63,

  MEP_LAST_PSEUDO_REGNUM = MEP_LAST_CCR_REGNUM,

  MEP_NUM_PSEUDO_REGS = (MEP_LAST_PSEUDO_REGNUM - MEP_LAST_RAW_REGNUM),

  MEP_NUM_REGS = MEP_NUM_RAW_REGS + MEP_NUM_PSEUDO_REGS

};

#define IN_SET(set, n) \

  (MEP_FIRST_ ## set ## _REGNUM <= (n) && (n) <= MEP_LAST_ ## set ## _REGNUM)

#define IS_GPR_REGNUM(n)     (IN_SET (GPR,     (n)))

#define IS_RAW_CSR_REGNUM(n) (IN_SET (RAW_CSR, (n)))

#define IS_RAW_CR_REGNUM(n)  (IN_SET (RAW_CR,  (n)))

#define IS_RAW_CCR_REGNUM(n) (IN_SET (RAW_CCR, (n)))

#define IS_CSR_REGNUM(n)     (IN_SET (CSR,     (n)))

#define IS_CR32_REGNUM(n)    (IN_SET (CR32,    (n)))

#define IS_FP_CR32_REGNUM(n) (IN_SET (FP_CR32, (n)))

#define IS_CR64_REGNUM(n)    (IN_SET (CR64,    (n)))

#define IS_FP_CR64_REGNUM(n) (IN_SET (FP_CR64, (n)))

#define IS_CR_REGNUM(n)      (IS_CR32_REGNUM (n) || IS_FP_CR32_REGNUM (n) \

                              || IS_CR64_REGNUM (n) || IS_FP_CR64_REGNUM (n))

#define IS_CCR_REGNUM(n)     (IN_SET (CCR,     (n)))

#define IS_RAW_REGNUM(n)     (IN_SET (RAW,     (n)))

#define IS_PSEUDO_REGNUM(n)  (IN_SET (PSEUDO,  (n)))

#define NUM_REGS_IN_SET(set) \

  (MEP_LAST_ ## set ## _REGNUM - MEP_FIRST_ ## set ## _REGNUM + 1)

#define MEP_GPR_SIZE (4)        /* Size of a MeP general-purpose register.  */

#define MEP_PSW_SIZE (4)        /* Size of the PSW register.  */

#define MEP_LP_SIZE (4)         /* Size of the LP register.  */

/* Many of the control/special registers contain bits that cannot be

   written to; some are entirely read-only.  So we present them all as

   pseudoregisters.

   The following table describes the special properties of each CSR.  */

struct mep_csr_register

{

  /* The number of this CSR's raw register.  */

  int raw;

  /* The number of this CSR's pseudoregister.  */

  int pseudo;

  /* A mask of the bits that are writeable: if a bit is set here, then

     it can be modified; if the bit is clear, then it cannot.  */

  LONGEST writeable_bits;

};

/* mep_csr_registers[i] describes the i'th CSR.

   We just list the register numbers here explicitly to help catch

   typos.  */

#define CSR(name) MEP_RAW_ ## name ## _REGNUM, MEP_ ## name ## _REGNUM

struct mep_csr_register mep_csr_registers[] = {

  { CSR(PC),    0xffffffff },   /* manual says r/o, but we can write it */

  { CSR(LP),    0xffffffff },

  { CSR(SAR),   0x0000003f },

  { CSR(CSR3),  0xffffffff },

  { CSR(RPB),   0xfffffffe },

  { CSR(RPE),   0xffffffff },

  { CSR(RPC),   0xffffffff },

  { CSR(HI),    0xffffffff },

  { CSR(LO),    0xffffffff },

  { CSR(CSR9),  0xffffffff },

  { CSR(CSR10), 0xffffffff },

  { CSR(CSR11), 0xffffffff },

  { CSR(MB0),   0x0000ffff },

  { CSR(ME0),   0x0000ffff },

  { CSR(MB1),   0x0000ffff },

  { CSR(ME1),   0x0000ffff },

  { CSR(PSW),   0x000003ff },

  { CSR(ID),    0x00000000 },

  { CSR(TMP),   0xffffffff },

  { CSR(EPC),   0xffffffff },

  { CSR(EXC),   0x000030f0 },

  { CSR(CFG),   0x00c0001b },

  { CSR(CSR22), 0xffffffff },

  { CSR(NPC),   0xffffffff },

  { CSR(DBG),   0x00000580 },

  { CSR(DEPC),  0xffffffff },

  { CSR(OPT),   0x00000000 },

  { CSR(RCFG),  0x00000000 },

  { CSR(CCFG),  0x00000000 },

  { CSR(CSR29), 0xffffffff },

  { CSR(CSR30), 0xffffffff },

  { CSR(CSR31), 0xffffffff },

};

/* If R is the number of a raw register, then mep_raw_to_pseudo[R] is

   the number of the corresponding pseudoregister.  Otherwise,

   mep_raw_to_pseudo[R] == R.  */

static int mep_raw_to_pseudo[MEP_NUM_REGS];

/* If R is the number of a pseudoregister, then mep_pseudo_to_raw[R]

   is the number of the underlying raw register.  Otherwise

   mep_pseudo_to_raw[R] == R.  */

static int mep_pseudo_to_raw[MEP_NUM_REGS];

static void

mep_init_pseudoregister_maps (void)

{

  int i;

  /* Verify that mep_csr_registers covers all the CSRs, in order.  */

  gdb_assert (ARRAY_SIZE (mep_csr_registers) == NUM_REGS_IN_SET (CSR));

  gdb_assert (ARRAY_SIZE (mep_csr_registers) == NUM_REGS_IN_SET (RAW_CSR));

  /* Verify that the raw and pseudo ranges have matching sizes.  */

  gdb_assert (NUM_REGS_IN_SET (RAW_CSR) == NUM_REGS_IN_SET (CSR));

  gdb_assert (NUM_REGS_IN_SET (RAW_CR)  == NUM_REGS_IN_SET (CR32));

  gdb_assert (NUM_REGS_IN_SET (RAW_CR)  == NUM_REGS_IN_SET (CR64));

  gdb_assert (NUM_REGS_IN_SET (RAW_CCR) == NUM_REGS_IN_SET (CCR));

  for (i = 0; i < ARRAY_SIZE (mep_csr_registers); i++)

    {

      struct mep_csr_register *r = &mep_csr_registers[i];

      gdb_assert (r->pseudo == MEP_FIRST_CSR_REGNUM + i);

      gdb_assert (r->raw    == MEP_FIRST_RAW_CSR_REGNUM + i);

    }

  /* Set up the initial  raw<->pseudo mappings.  */

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

    {

      mep_raw_to_pseudo[i] = i;