hal_misc.c

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//==========================================================================
//
//      hal_misc.c
//
//      HAL miscellaneous functions
//
//==========================================================================
//####ECOSGPLCOPYRIGHTBEGIN####
// -------------------------------------------
// This file is part of eCos, the Embedded Configurable Operating System.
// Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.
// Copyright (C) 2006 eCosCentric Ltd.
//
// 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.
// -------------------------------------------
//####ECOSGPLCOPYRIGHTEND####
//==========================================================================
//#####DESCRIPTIONBEGIN####
//
// Author(s):     Enrico Piria
// Contributors:
// Date:          2005-25-06
// Purpose:       Miscellaneous routine and variable definitions.
//
//####DESCRIPTIONEND####
//========================================================================

#include <pkgconf/hal.h>

#include <cyg/infra/cyg_type.h>
#include <cyg/infra/cyg_trac.h>         // tracing macros
#include <cyg/infra/cyg_ass.h>          // assertion macros
#include <cyg/infra/diag.h>             // diag_printf

#include <cyg/hal/hal_arch.h>           // HAL header

#include <cyg/hal/hal_intr.h>           // VSR/ISR defines

// -------------------------------------------------------------------------
// ISR table

volatile CYG_ADDRESS  cyg_hal_interrupt_handlers[CYGNUM_HAL_ISR_COUNT];
volatile CYG_ADDRWORD cyg_hal_interrupt_data[CYGNUM_HAL_ISR_COUNT];
volatile CYG_ADDRESS  cyg_hal_interrupt_objects[CYGNUM_HAL_ISR_COUNT];

// -------------------------------------------------------------------------
// VSR table

externC void __handle_exception(void);

externC HAL_SavedRegisters * _hal_registers;

#ifdef CYGDBG_HAL_DEBUG_GDB_INCLUDE_STUBS
externC void* volatile __mem_fault_handler;
#endif

// Defined in variant HAL
externC void hal_interrupt_update_level(void);

// --------------------------------------------------------------------------
// Default exception handler.

void hal_exception_handler(CYG_WORD vector, HAL_SavedRegisters *regs)
{

#ifdef CYGDBG_HAL_DEBUG_GDB_INCLUDE_STUBS

    // If we caught an exception inside the stubs, see if we were expecting it
    // and if so jump to the saved address.
    if (__mem_fault_handler) {
        regs->pc = (CYG_ADDRWORD)__mem_fault_handler;
        // Caught an exception inside stubs
        return;
    }

    // Set the pointer to the registers of the current exception
    // context. At entry the GDB stub will expand the
    // HAL_SavedRegisters structure into a (bigger) register array.
    _hal_registers = regs;

    __handle_exception();

#elif defined(CYGFUN_HAL_COMMON_KERNEL_SUPPORT) && \
      defined(CYGPKG_HAL_EXCEPTIONS)

    // We should decode the vector and pass a more appropriate
    // value as the second argument. For now we simply pass a
    // pointer to the saved registers. We should also divert
    // breakpoint and other debug vectors into the debug stubs.

    cyg_hal_deliver_exception(vector, (CYG_ADDRWORD)regs);

#else

    CYG_FAIL("Exception!!!");

#endif

    return;
}

// --------------------------------------------------------------------------
// Default ISR handler.

cyg_uint32 hal_arch_default_isr(CYG_ADDRWORD vector, CYG_ADDRWORD data)
{
    CYG_FAIL("Unexpected ISR");
    return 0;
}

// --------------------------------------------------------------------------
// Default spurious interrupt handler. This routine is called with all
// interrupts disabled.

#ifndef CYGIMP_HAL_COMMON_INTERRUPTS_IGNORE_SPURIOUS

void hal_spurious_interrupt(HAL_SavedRegisters *regs) CYGBLD_ATTRIB_WEAK;

void hal_spurious_interrupt(HAL_SavedRegisters *regs)
{
    CYG_FAIL("Spurious interrupt!!");
}

#endif

// --------------------------------------------------------------------------
// Idle thread action.

void hal_idle_thread_action(cyg_uint32 count)
{
}

// -----------------------------------------------------------------------
// Determine the index of the ls bit of the supplied mask.

cyg_uint32 hal_lsbit_index(cyg_uint32 mask)
{
    cyg_uint32 n = mask;

    static const signed char tab[64] =
    { -1, 0, 1, 12, 2, 6, 0, 13, 3, 0, 7, 0, 0, 0, 0, 14, 10,
      4, 0, 0, 8, 0, 0, 25, 0, 0, 0, 0, 0, 21, 27 , 15, 31, 11,
      5, 0, 0, 0, 0, 0, 9, 0, 0, 24, 0, 0 , 20, 26, 30, 0, 0, 0,
      0, 23, 0, 19, 29, 0, 22, 18, 28, 17, 16, 0
    };

    n &= ~(n-1UL);
    n = (n<<16)-n;
    n = (n<<6)+n;
    n = (n<<4)+n;

    return tab[n>>26];
}

// -----------------------------------------------------------------------
// Determine the index of the ms bit of the supplied mask.

cyg_uint32 hal_msbit_index(cyg_uint32 mask)
{
    cyg_uint32 x = mask;    
    cyg_uint32 w;

    // Phase 1: make word with all ones from that one to the right
    x |= x >> 16;
    x |= x >> 8;
    x |= x >> 4;
    x |= x >> 2;
    x |= x >> 1;

    // Phase 2: calculate number of "1" bits in the word
    w = (x & 0x55555555) + ((x >> 1) & 0x55555555);
    w = (w & 0x33333333) + ((w >> 2) & 0x33333333);
    w = w + (w >> 4);
    w = (w & 0x000F000F) + ((w >> 8) & 0x000F000F);
    return (cyg_uint32)((w + (w >> 16)) & 0xFF) - 1;

}