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/* GNU/Linux/or32 specific low level interface, for the remote server for GDB.

   Copyright (C) 2005, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.

   Copyright (C) 2010 Embecosm Limited

   Contributor Jeremy Bennett <jeremy.bennett@embecosm.com>

   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/>.  */

/* -------------------------------------------------------------------------- */

/* OpenRISC 1000 specific low level Linux interface for GDB server.

   This implementation includes full Doxygen compatible documentation         */

/* -------------------------------------------------------------------------- */

#ifdef HAVE_STRINGS_H

#include <strings.h>

#endif

#include "server.h"

#include "regdef.h"

#include "linux-low.h"

#include <asm/ptrace.h> /* For openrisc kernel ptrace register offsets */

/* Defined in auto-generated file reg-or32.c.  */

void init_registers_or32 (void);

#ifdef HAVE_SYS_REG_H

#include <sys/reg.h>

#endif

/*! Some useful GDB register numbers. */

#define GDB_REGNUM_R0    0

#define GDB_REGNUM_R31  31

#define GDB_REGNUM_PPC  32

#define GDB_REGNUM_NPC  33

#define GDB_REGNUM_SR   34

/*! This is the number of *GDB* registers. I.e. r0-r31, PPC, NPC and SR. */

#define or32_num_regs  (GDB_REGNUM_SR + 1)

/* -------------------------------------------------------------------------- */

/*!Provide the ptrace "address" of a register.

   This must be in GDB order (r0-r1, ppc, npc, sr) to ptrace offset. As with

   regs_or32, we substitute r31 for r0 and NPC for PPC.                       */

/* -------------------------------------------------------------------------- */

static int or32_regmap[] = {

  PT_GPR31, PT_SP,    PT_GPR2,  PT_GPR3,

  PT_GPR4,  PT_GPR5,  PT_GPR6,  PT_GPR7,

  PT_GPR8,  PT_GPR9,  PT_GPR10, PT_GPR11,

  PT_GPR12, PT_GPR13, PT_GPR14, PT_GPR15,

  PT_GPR16, PT_GPR17, PT_GPR18, PT_GPR19,

  PT_GPR20, PT_GPR21, PT_GPR22, PT_GPR23,

  PT_GPR24, PT_GPR25, PT_GPR26, PT_GPR27,

  PT_GPR28, PT_GPR29, PT_GPR30, PT_GPR31,

  PT_PC,    PT_PC,    PT_SR

};

/* -------------------------------------------------------------------------- */

/*!Predicate to indicate if a register can be read.

   We mark r0 as not readable.

   @param[in] regno  Register to read.

   @return  Non-zero (TRUE) if the register can be read, zero (FALSE)

            otherwise.                                                        */

/* -------------------------------------------------------------------------- */

static int

or32_cannot_fetch_register (int  regno)

{

  return (GDB_REGNUM_R0 == regno) || (regno >= or32_num_regs);

}       /* or32_cannot_fetch_register () */

/* -------------------------------------------------------------------------- */

/*!Predicate to indicate if a register can be written.

   We mark r0 and the SR as not writeable.

   @param[in] regno  Register to write.

   @return  Non-zero (TRUE) if the register can be written, zero (FALSE)

            otherwise.                                                        */

/* -------------------------------------------------------------------------- */

static int

or32_cannot_store_register (int  regno)

{

  return (GDB_REGNUM_R0 == regno) || (GDB_REGNUM_SR == regno) ||

         (regno >= or32_num_regs);

}       /* or32_cannot_store_register () */

/* -------------------------------------------------------------------------- */

/*!Get the current program counter.

   On the OR32, this is NPC, the *next* program counter.

   @param[in] regcache  Current register cache.

   @return  The value of the NPC.                                             */

/* -------------------------------------------------------------------------- */

static CORE_ADDR

or32_get_pc (struct regcache *regcache)

{

  unsigned long int  npc;

  collect_register_by_name (regcache, "pc", &npc);

    if (debug_threads)

    {

      fprintf (stderr, "stop pc is %08lx\n", npc);

    }

  return  npc;

}       /* or32_get_pc () */

/* -------------------------------------------------------------------------- */

/*!Set the current program counter.

   On the OR32, this is NPC, the *next* program counter.

   @param[in] regcache  Current register cache.

   @param[in] pc        The value of the program counter to set.              */

/* -------------------------------------------------------------------------- */

static void

or32_set_pc (struct regcache *regcache,

             CORE_ADDR        pc)

{

  unsigned long int  npc = pc;

  supply_register_by_name (regcache, "pc", &npc);

}       /* or32_set_pc () */

/*! The value of a breakpoint instruction (l.trap  1). */

static const unsigned char or32_breakpoint [] = {0x21, 0x00, 0x00, 0x01};

/*! The length of a breakpoint instruction. */

#define OR32_BREAKPOINT_LEN  4

/* -------------------------------------------------------------------------- */

/*!Predicate to indicate if there is a breakpoint at the current address.

   For the OR32 we, just look for the l.trap 1 instruction.

   @param[in] where  The address to look for a breakpoint at.

   @return  Non-zero (TRUE) if there is a breakpoint, zero (FALSE) otherwise. */

/* -------------------------------------------------------------------------- */

static int

or32_breakpoint_at (CORE_ADDR where)

{

  unsigned char  insn[OR32_BREAKPOINT_LEN];

  (*the_target->read_memory) (where, insn, OR32_BREAKPOINT_LEN);

  return  (0 ==  bcmp (insn, or32_breakpoint, OR32_BREAKPOINT_LEN));

}       /* or32_breakpoint_at () */

/* -------------------------------------------------------------------------- */

/*!Data structure giving all the target specific functions.

   Details are in struct linux_target_ops in linux-low.h.                     */

/* -------------------------------------------------------------------------- */

struct linux_target_ops the_low_target = {

  init_registers_or32,                  /* Arch initialization */

  or32_num_regs,                        /* Num regs in arch */

  or32_regmap,                          /* Reg offsets for ptrace */

  or32_cannot_fetch_register,           /* Predicate for reg reading */

  or32_cannot_store_register,           /* Predicate for reg writing */

  or32_get_pc,                          /* Read the PC */

  or32_set_pc,                          /* Write the PC */

  or32_breakpoint,                      /* Breakpoint instruction bytes */

  OR32_BREAKPOINT_LEN,                  /* Breakpoint length */

  NULL,                                 /* Breakpoint reinsertion (unused) */

  0,                                     /* Decrement PC after break (FALSE) */

  or32_breakpoint_at,                   /* Predicate to check for breakpoint */

  NULL,                                 /* Insert watchpoint (unused) */

  NULL,                                 /* Remove watchpoint (unused) */

  NULL,                                 /* Predicate if stopped by watchpoint */

  NULL,                                 /* Data address for watchpoint stop */

  NULL,                                 /* ptrace PEEKUSR hook */

  NULL,                                 /* ptrace POKEUSR hook */

  NULL,                                 /* ptrace conversion predicate */

  NULL,                                 /* New process hook */

  NULL,                                 /* New thread hook */

  NULL,                                 /* Prepare to resume thread */

  NULL,                                 /* Target specific qSupported */

  NULL,                                 /* Tracepoint supported predicate */

  NULL,                                 /* Get thread area address */

  NULL,                                 /* Fast tracepoint jump pad */

  NULL,                                 /* Get bytecode operations vector */

};