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/*==========================================================================

//

//      cortexm_stub.c

//

//      Cortex-M GDB stub support

//

//==========================================================================

// ####ECOSGPLCOPYRIGHTBEGIN####

// -------------------------------------------

// This file is part of eCos, the Embedded Configurable Operating System.

// Copyright (C) 2008 Free Software Foundation, Inc.

//

// eCos 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 2 or (at your option) any later

// version.

//

// eCos 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 eCos; if not, write to the Free Software Foundation, Inc.,

// 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

//

// As a special exception, if other files instantiate templates or use

// macros or inline functions from this file, or you compile this file

// and link it with other works to produce a work based on this file,

// this file does not by itself cause the resulting work to be covered by

// the GNU General Public License. However the source code for this file

// must still be made available in accordance with section (3) of the GNU

// General Public License v2.

//

// This exception does not invalidate any other reasons why a work based

// on this file might be covered by the GNU General Public License.

// -------------------------------------------

// ####ECOSGPLCOPYRIGHTEND####

//==========================================================================

//#####DESCRIPTIONBEGIN####

//

// Author(s):    nickg

// Date:         2008-07-30

//

//####DESCRIPTIONEND####

//

//========================================================================*/

#include <stddef.h>

#include <pkgconf/hal.h>

#ifdef CYGPKG_REDBOOT

#include <pkgconf/redboot.h>

#endif

#ifdef CYGDBG_HAL_DEBUG_GDB_INCLUDE_STUBS

#include <cyg/hal/hal_arch.h>

#include <cyg/hal/hal_intr.h>

#include <cyg/hal/hal_stub.h>

//==========================================================================

#ifndef FALSE

#define FALSE 0

#define TRUE  1

#endif

#ifdef CYGDBG_HAL_DEBUG_GDB_THREAD_SUPPORT

#include <cyg/hal/dbg-threads-api.h>    // dbg_currthread_id

#endif

//==========================================================================

/* Given a trap value TRAP, return the corresponding signal. */

int __computeSignal (unsigned int trap_number)

{

    switch (trap_number)

    {

    case CYGNUM_HAL_VECTOR_BUS_FAULT:      // Fall through

    case CYGNUM_HAL_VECTOR_MEMORY_MAN:     // Fall through

        return SIGBUS;

    case CYGNUM_HAL_VECTOR_NMI:

    case CYGNUM_HAL_VECTOR_SYS_TICK:

        return SIGINT;

    default:

        return SIGTRAP;

    }

}

//==========================================================================

/* Return the trap number corresponding to the last-taken trap. */

int __get_trap_number (void)

{

    // The vector is not not part of the GDB register set so get it

    // directly from the save context.

    return _hal_registers->u.exception.vector;

}

//==========================================================================

/* Set the currently-saved pc register value to PC. */

void set_pc (target_register_t pc)

{

    put_register (PC, pc);

}

//==========================================================================

// Calculate byte offset a given register from start of register save area.

static int

reg_offset(regnames_t reg)

{

    int base_offset;

    if (reg < F0)

        return reg * 4;

    base_offset = 16 * 4;

    if (reg < FPS)

        return base_offset + ((reg - F0) * 12);

    base_offset += (8 * 12);

    if (reg <= PS)

        return base_offset + ((reg - FPS) * 4);

    return -1;  // Should never happen!

}

//==========================================================================

// Return the currently-saved value corresponding to register REG of

// the exception context.

target_register_t

get_register (regnames_t reg)

{

    target_register_t val;

    int offset = reg_offset(reg);

    if (REGSIZE(reg) > sizeof(target_register_t) || offset == -1)

        return -1;

    val = _registers[offset/sizeof(target_register_t)];

    return val;

}

//==========================================================================

// Store VALUE in the register corresponding to WHICH in the exception

// context.

void

put_register (regnames_t which, target_register_t value)

{

    int offset = reg_offset(which);

    if (REGSIZE(which) > sizeof(target_register_t) || offset == -1)

        return;

    _registers[offset/sizeof(target_register_t)] = value;

}

//==========================================================================

// Write the contents of register WHICH into VALUE as raw bytes. This

// is only used for registers larger than sizeof(target_register_t).

// Return non-zero if it is a valid register.

int

get_register_as_bytes (regnames_t which, char *value)

{

    int offset = reg_offset(which);

    if (offset != -1) {

        memcpy (value, (char *)_registers + offset, REGSIZE(which));

        return 1;

    }

    return 0;

}

//==========================================================================

// Alter the contents of saved register WHICH to contain VALUE. This

// is only used for registers larger than sizeof(target_register_t).

// Return non-zero if it is a valid register.

int

put_register_as_bytes (regnames_t which, char *value)

{

    int offset = reg_offset(which);

    if (offset != -1) {

        memcpy ((char *)_registers + offset, value, REGSIZE(which));

        return 1;

    }

    return 0;

}

//==========================================================================

// Single step the processor.

//

// We do this by setting the MON_STEP bit in the DEMCR. So long as we

// are in a DebugMonitor exception this will single step the CPU on

// return.

// We also need to block all pending interrupts by setting basepri

// before doing the step. Otherwise an interrupt may be delivered

// before the step happens, and may cause unpleasant things to happen.

cyg_uint32 __single_step_basepri = 0;

void __single_step (void)

{

    CYG_ADDRESS base = CYGARC_REG_DEBUG_BASE;

    cyg_uint32 demcr;

    // Save basepri and set it to mask all interrupts.

    __single_step_basepri = _hal_registers->u.exception.basepri;

    _hal_registers->u.exception.basepri = CYGNUM_HAL_CORTEXM_PRIORITY_MAX;

    // Set MON_STEP

    HAL_READ_UINT32( base+CYGARC_REG_DEBUG_DEMCR, demcr );

    demcr |= CYGARC_REG_DEBUG_DEMCR_MON_STEP;

    HAL_WRITE_UINT32( base+CYGARC_REG_DEBUG_DEMCR, demcr );

    // Clear any bits set in DFSR

    base = CYGARC_REG_NVIC_BASE;

    HAL_WRITE_UINT32( base+CYGARC_REG_NVIC_DFSR, 0xFFFFFFFF );

}

//==========================================================================

// Clear the single-step state.

void __clear_single_step (void)

{

    CYG_ADDRESS base = CYGARC_REG_DEBUG_BASE;

    cyg_uint32 demcr;

    // Restore basepri

    _hal_registers->u.exception.basepri = __single_step_basepri;

    // Clear MON_STEP

    HAL_READ_UINT32( base+CYGARC_REG_DEBUG_DEMCR, demcr );

    demcr &= ~CYGARC_REG_DEBUG_DEMCR_MON_STEP;

    HAL_WRITE_UINT32( base+CYGARC_REG_DEBUG_DEMCR, demcr );

    // Clear any bits set in DFSR

    base = CYGARC_REG_NVIC_BASE;

    HAL_WRITE_UINT32( base+CYGARC_REG_NVIC_DFSR, 0xFFFFFFFF );

}

//==========================================================================

void __install_breakpoints (void)

{

    __install_breakpoint_list();

}

//--------------------------------------------------------------------------

void __clear_breakpoints (void)

{

    __clear_breakpoint_list();

}

//--------------------------------------------------------------------------

/* If the breakpoint we hit is in the breakpoint() instruction, return a

   non-zero value. */

int

__is_breakpoint_function ()

{

    return get_register (PC) == (target_register_t)&_breakinst;

}

//--------------------------------------------------------------------------

/* Skip the current instruction.  Since this is only called by the

   stub when the PC points to a breakpoint or trap instruction,

   we can safely just skip 2. */

void __skipinst (void)

{

    unsigned long pc = get_register(PC);

    pc += 2;

    put_register(PC, pc);

}

//==========================================================================

#endif // CYGDBG_HAL_DEBUG_GDB_INCLUDE_STUBS