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//==========================================================================
//
//      hal_misc.c
//
//      HAL miscellaneous functions
//
//==========================================================================
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// -------------------------------------------                              
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//
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// ####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;
 
}