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

//

//      frv_stub.c

//

//      Helper functions for stub, generic to all FUJITSU processors

//

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

//####ECOSGPLCOPYRIGHTBEGIN####

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

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

// Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, 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.,

// 59 Temple Place, Suite 330, Boston, MA 02111-1307 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.

//

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

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

//

// Alternative licenses for eCos may be arranged by contacting Red Hat, Inc.

// at http://sources.redhat.com/ecos/ecos-license/

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

//####ECOSGPLCOPYRIGHTEND####

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

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

//

// Author(s):     Red Hat, gthomas

// Contributors:  Red Hat, gthomas, jskov, msalter

// Date:          2001-09-16

// Purpose:       

// Description:   Helper functions for stub, generic to all FUJITSU processors

// Usage:         

//

//####DESCRIPTIONEND####

//

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

#include <pkgconf/hal.h>

#ifdef CYGPKG_REDBOOT

#include <pkgconf/redboot.h>

#endif

#ifdef CYGDBG_HAL_DEBUG_GDB_INCLUDE_STUBS

#include <cyg/hal/hal_stub.h>

#include <cyg/hal/hal_arch.h>

#include <cyg/hal/hal_intr.h>

#include <cyg/hal/hal_cache.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

#if defined(CYGNUM_HAL_BREAKPOINT_LIST_SIZE) && (CYGNUM_HAL_BREAKPOINT_LIST_SIZE > 0)

cyg_uint32 __frv_breakinst = HAL_BREAKINST;

#endif

// Sadly, this doesn't seem to work on the FRV400 either

//#define USE_HW_STEP  

#ifdef CYGSEM_HAL_FRV_HW_DEBUG

static inline unsigned __get_dcr(void)

{

    unsigned retval;

    asm volatile (

        "movsg   dcr,%0\n"

        : "=r" (retval)

        : /* no inputs */  );

    return retval;

}

static inline void __set_dcr(unsigned val)

{

    asm volatile (

        "movgs   %0,dcr\n"

        : /* no outputs */

        : "r" (val) );

}

#endif

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

int __computeSignal (unsigned int trap_number)

{

    // should also catch CYGNUM_HAL_VECTOR_UNDEF_INSTRUCTION here but we

    // can't tell the different between a real one and a breakpoint :-(

    switch (trap_number) {

      // Interrupts

    case CYGNUM_HAL_VECTOR_EXTERNAL_INTERRUPT_LEVEL_1 ... CYGNUM_HAL_VECTOR_EXTERNAL_INTERRUPT_LEVEL_15:

        return SIGINT;

    case CYGNUM_HAL_VECTOR_INSTR_ACCESS_MMU_MISS:

    case CYGNUM_HAL_VECTOR_INSTR_ACCESS_ERROR:

    case CYGNUM_HAL_VECTOR_INSTR_ACCESS_EXCEPTION:

    case CYGNUM_HAL_VECTOR_MEMORY_ADDRESS_NOT_ALIGNED:

    case CYGNUM_HAL_VECTOR_DATA_ACCESS_ERROR:

    case CYGNUM_HAL_VECTOR_DATA_ACCESS_MMU_MISS:

    case CYGNUM_HAL_VECTOR_DATA_ACCESS_EXCEPTION:

    case CYGNUM_HAL_VECTOR_DATA_STORE_ERROR:

        return SIGBUS;

    case CYGNUM_HAL_VECTOR_PRIVELEDGED_INSTRUCTION:

    case CYGNUM_HAL_VECTOR_ILLEGAL_INSTRUCTION:

    case CYGNUM_HAL_VECTOR_REGISTER_EXCEPTION:

    case CYGNUM_HAL_VECTOR_FP_DISABLED:

    case CYGNUM_HAL_VECTOR_MP_DISABLED:

    case CYGNUM_HAL_VECTOR_FP_EXCEPTION:

    case CYGNUM_HAL_VECTOR_MP_EXCEPTION:

    case CYGNUM_HAL_VECTOR_DIVISION_EXCEPTION:

    case CYGNUM_HAL_VECTOR_COMMIT_EXCEPTION:

    case CYGNUM_HAL_VECTOR_COMPOUND_EXCEPTION:

      return SIGILL;

    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->vector;

}

#if defined(CYGSEM_REDBOOT_BSP_SYSCALLS)

int __is_bsp_syscall(void)

{

  // Might want to be more specific here

  return (_hal_registers->vector == CYGNUM_HAL_VECTOR_SYSCALL);

}

#endif // defined(CYGSEM_REDBOOT_BSP_SYSCALLS)

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

void set_pc (target_register_t pc)

{

    put_register (PC, pc);

}

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

 * Single-step support

 */

/* Set things up so that the next user resume will execute one instruction.

   This may be done by setting breakpoints or setting a single step flag

   in the saved user registers, for example. */

#ifndef CYGSEM_HAL_FRV_HW_DEBUG

#if CYGINT_HAL_FRV_ARCH_FR400 == 1

#define VLIW_DEPTH 2

#endif

#if CYGINT_HAL_FRV_ARCH_FR500 == 1

#define VLIW_DEPTH 4

#endif

/*

 * Structure to hold opcodes hoisted when breakpoints are

 * set for single-stepping or async interruption.

 */

struct _bp_save {

    unsigned long  *addr;

    unsigned long   opcode;

};

/*

 * We single-step by setting breakpoints.

 *

 * This is where we save the original instructions.

 */

static struct _bp_save step_bp[VLIW_DEPTH+1];

//**************************************************************

//************ CAUTION!! ***************************************

//**************************************************************

//

// Attempt to analyze the current instruction.  This code is not

// perfect in the case of VLIW sequences, although it's close.

// Consider these sequences:

//

//      ldi.p   @(gr5,0),gr4

//      jmpl    @(gr4,gr0)

// and 

//

//      ldi.p   @(gr5,0),gr4

//      add.p   gr6,gr7,gr8

//      jmpl    @(gr4,gr0)

//

// In these cases, the only way to effectively calculate the 

// target address (of the jump) would be to simulate the actions

// of the pipelined instructions which come beforehand.

//

// Of course, this only affects single stepping through a VLIW

// sequence which contains such pipelined effects and a branch.

// Hopefully this is rare.

//

// Note: testing of the above sequence on the FR400 yielded an

// illegal instruction (invalid VLIW sequence), so this may not

// turn out to be a problem in practice, just theory.

//

//**************************************************************

//**************************************************************

static int

_analyze_instr(unsigned long pc, unsigned long *targ,

               unsigned long *next, int *is_vliw)

{

    unsigned long opcode;

    int n, is_branch = 0;

    opcode = *(unsigned long *)pc;

    switch ((opcode >> 18) & 0x7f) {

    case 6:

    case 7:

        /* bcc, fbcc */

        is_branch = 1;

        n = (int)(opcode << 16);

        n >>= 16;

        *targ = pc + n*4;

        pc += 4;

        break;

    case 12:

        /* jmpl */

        n = (int)(get_register((opcode>>12)&63));

        n += (int)(get_register(opcode&63));

        pc = n;

        break;

    case 13:

        /* jmpil */

        n = (int)(get_register((opcode>>12)&63));

        n += (((int)(opcode << 20)) >> 20);

        pc = n;

        break;

    case 15:

        /* call */

        n = (opcode >> 25) << 18;

        n |= (opcode & 0x3ffff);

        n <<= 8;

        n >>= 8;

        pc += n*4;

        break;

    case 14:

        /* ret */

        is_branch = 1;

        *targ = get_register(LR);

        pc += 4;

        break;

    default:

        pc += 4;

        break;

    }

    *next = pc;

    *is_vliw = (opcode & 0x80000000) == 0;

    return is_branch;

}

#endif

void __single_step (void)

{

#ifdef CYGSEM_HAL_FRV_HW_DEBUG

    __set_dcr(__get_dcr() | _DCR_SE);

    diag_printf("Setting single step - DCR: %x\n", __get_dcr());

#else

    unsigned long pc, targ, next_pc;

    int i, is_branch = 0;

    int is_vliw;

    for (i = 0;  i < VLIW_DEPTH+1;  i++) {

        step_bp[i].addr = NULL;

    }

    pc = get_register(PC);

    i = 1;

    while (i < (VLIW_DEPTH+1)) {

        is_branch = _analyze_instr(pc, &targ, &next_pc, &is_vliw);

        if (is_branch && next_pc != targ) {

            step_bp[i].addr = (unsigned long *)targ;

            step_bp[i].opcode = *(unsigned long *)targ;

            *(unsigned long *)targ = HAL_BREAKINST;

            HAL_DCACHE_STORE(targ, 4);

            HAL_ICACHE_INVALIDATE(targ, 4);

        }

        if (is_vliw) {

            pc += 4;

            i++;

        } else {

            break;

        }

    }

    step_bp[0].addr = (unsigned long *)next_pc;

    step_bp[0].opcode = *(unsigned long *)next_pc;

    *(unsigned long *)next_pc = HAL_BREAKINST;

    HAL_DCACHE_STORE(next_pc, 4);

    HAL_ICACHE_INVALIDATE(next_pc, 4);

#endif

}

/* Clear the single-step state. */

void __clear_single_step (void)

{

#ifdef CYGSEM_HAL_FRV_HW_DEBUG

    __set_dcr(__get_dcr() & ~_DCR_SE);

#else

    struct _bp_save *p;

    int i;

    for (i = 0;  i < VLIW_DEPTH+1;  i++) {

        p = &step_bp[i];

        if (p->addr) {

            *(p->addr) = p->opcode;

            HAL_DCACHE_STORE((cyg_uint32)p->addr, 4);

            HAL_ICACHE_INVALIDATE((cyg_uint32)p->addr, 4);

            p->addr = NULL;

        }

    }

#endif

}

void __install_breakpoints (void)

{

#if defined(CYGNUM_HAL_BREAKPOINT_LIST_SIZE) && (CYGNUM_HAL_BREAKPOINT_LIST_SIZE > 0)

    /* Install the breakpoints in the breakpoint list */

    __install_breakpoint_list();

#endif

}

void __clear_breakpoints (void)

{

#if defined(CYGNUM_HAL_BREAKPOINT_LIST_SIZE) && (CYGNUM_HAL_BREAKPOINT_LIST_SIZE > 0)

    __clear_breakpoint_list();

#endif

}

/* 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 4. */

void __skipinst (void)

{

    unsigned long pc = get_register(PC);

    pc += 4;

    put_register(PC, pc);

}

#endif // CYGDBG_HAL_DEBUG_GDB_INCLUDE_STUBS