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

//

//      openrisc_stub.c

//

//      OpenRISC-specific code for remote debugging via gdb

//

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

//####ECOSGPLCOPYRIGHTBEGIN####

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

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

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

//

// Author(s):     sfurman

// Contributors:  Red Hat, jskov, gthomas

// Date:          2003-02-07

// Purpose:       

// Description:   Helper functions for gdb stub for OpenRISC processors

// Usage:         

//

//####DESCRIPTIONEND####

//

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

#include <stddef.h>

#include <pkgconf/hal.h>

#ifdef CYGDBG_HAL_DEBUG_GDB_INCLUDE_STUBS

#define CYGARC_HAL_COMMON_EXPORT_CPU_MACROS

#include <cyg/hal/hal_stub.h>

#include <cyg/hal/hal_arch.h>

#include <cyg/hal/hal_intr.h>

#include <cyg/hal/openrisc_opcode.h>

#include <cyg/infra/cyg_ass.h>          // assertion macros

#ifdef CYGNUM_HAL_NO_VECTOR_TRACE

#define USE_BREAKPOINTS_FOR_SINGLE_STEP

#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)

    {

        // Either no matching page-table entry or protection fault

        // while executing load/store operation

    case CYGNUM_HAL_VECTOR_DATA_PAGE_FAULT:

        // Either no matching page-table entry or protection fault

        // while executing load/store operation

    case CYGNUM_HAL_VECTOR_INSTR_PAGE_FAULT:

        return SIGSEGV;

        // No matching entry in D-TLB

    case CYGNUM_HAL_VECTOR_DTLB_MISS:

        // No matching entry in I-TLB

    case CYGNUM_HAL_VECTOR_ITLB_MISS:

        // Unaligned load/store memory access

    case CYGNUM_HAL_VECTOR_UNALIGNED_ACCESS:

        // Access to non-existent physical memory/device

    case CYGNUM_HAL_VECTOR_BUS_ERROR:

        return SIGBUS;

        // TRAP instruction executed

    case CYGNUM_HAL_VECTOR_TRAP:

        return SIGTRAP;

        /* System call instruction executed */

    case CYGNUM_HAL_VECTOR_SYSTEM_CALL:

        return SIGSYS;

        /* Tick timer interrupt fired */

    case CYGNUM_HAL_VECTOR_TICK_TIMER:

        return SIGALRM;

        /* External interrupt */

    case CYGNUM_HAL_VECTOR_INTERRUPT:

      return SIGINT;

      // Illegal or reserved instruction

    case CYGNUM_HAL_VECTOR_RESERVED_INSTRUCTION:

        return SIGILL;

        // Numeric overflow, etc.

    case CYGNUM_HAL_VECTOR_RANGE:

        return SIGFPE;

    default:

        return SIGTERM;

    }

}

/* 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;

}

/* Set the currently-saved pc register value to PC. This also updates NPC

   as needed. */

void set_pc (target_register_t pc)

{

    put_register (PC, pc);

}

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

 * Single-step support

 */

// Type of a single OpenRISC instruction

typedef cyg_uint32 t_inst;

/* Saved instruction data for single step support.  */

static struct

{

  t_inst *targetAddr;

  t_inst savedInstr;

} instrBuffer;

/* 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. */

void __single_step (void)

{

  t_inst *pc = (t_inst *) get_register (PC);

  t_inst *targetAddr;

  InstFmt insn;

  int flag;

  targetAddr = pc + 1;              /* set default */

  insn.word = *pc;

  switch (insn.JType.op) {

  case OP_J:

  case OP_JAL:

    targetAddr = pc + insn.JType.target;

    break;

  case OP_BNF:

    flag = get_register(SR) & SPR_SR_F;

    if (!flag)

      targetAddr = pc + insn.JType.target;

    break;

  case OP_BF:

    flag = get_register(SR) & SPR_SR_F;

    if (flag)

      targetAddr = pc + insn.JType.target;

    break;

  case OP_JR:

  case OP_JALR:

    targetAddr = (t_inst*)get_register(insn.JRType.rB);

    break;

    /* We don't step into interrupts, syscalls or traps */

  default:

    break;

  }

  instrBuffer.targetAddr = targetAddr;

  instrBuffer.savedInstr = *targetAddr;

  *targetAddr = __break_opcode ();

  // No need to flush caches; Generic stub code will handle this.

}

/* Clear the single-step state. */

void __clear_single_step (void)

{

  if (instrBuffer.targetAddr != NULL)

    {

      *instrBuffer.targetAddr = instrBuffer.savedInstr;

      instrBuffer.targetAddr = NULL;

      instrBuffer.savedInstr = 0;

    }

}

void __install_breakpoints ()

{

  /*  if (instrBuffer.targetAddr != NULL)

    {

      instrBuffer.savedInstr = *instrBuffer.targetAddr;

      *instrBuffer.targetAddr = __break_opcode ();

      } */

  /* Install the breakpoints in the breakpoint list */

  __install_breakpoint_list();

  // No need to flush caches here; Generic stub code will handle this.

}

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 4. */

void __skipinst (void)

{

    put_register (PC, get_register (PC) + 4);

}

target_register_t

get_register (regnames_t reg)

{

    GDB_Registers* gdb_regs;

    gdb_regs = (GDB_Registers*)_registers;

    if (reg >= R0 && reg <= R31)

        return gdb_regs->r[reg];

    if (reg == PC)

        return gdb_regs->pc;

    if (reg == SR)

        return gdb_regs->sr;

    return 0xdeadbeef;

}

void

put_register (regnames_t reg, target_register_t value)

{

    GDB_Registers* gdb_regs;

    gdb_regs = (GDB_Registers*)_registers;

    if (reg >= R0 && reg <= R31) {

        gdb_regs->r[reg] = value;

    } else if (reg == PC) {

        gdb_regs->pc = value;

    } else if (reg == SR) {

        gdb_regs->sr = value;

    } else {

        CYG_FAIL("Attempt to write to non-existent register ");

    }

}

#endif // CYGDBG_HAL_DEBUG_GDB_INCLUDE_STUBS