xref: /gem5/ext/systemc/src/sysc/datatypes/fx/scfx_mant.cpp

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

  scfx_mant.cpp -

  Original Author: Robert Graulich, Synopsys, Inc.
                   Martin Janssen,  Synopsys, Inc.

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

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

  MODIFICATION LOG - modifiers, enter your name, affiliation, date and
  changes you are making here.

      Name, Affiliation, Date:
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// $Log: scfx_mant.cpp,v $
// Revision 1.1.1.1  2006/12/15 20:20:04  acg
// SystemC 2.3
//
// Revision 1.3  2006/01/13 18:53:58  acg
// Andy Goodrich: added $Log command so that CVS comments are reproduced in
// the source.
//

#include "sysc/datatypes/fx/scfx_mant.h"


namespace sc_dt
{

// ----------------------------------------------------------------------------
//  word memory management
// ----------------------------------------------------------------------------

class word_list { // Entry in free_words bucket.
  public:
    word_list* m_next_p;
};

static inline
int
next_pow2_index( std::size_t size )
{
    int index = scfx_find_msb( size );
    // If this was a power of 2 we are one bucket too low.
    if( ~ (1 << index) & size ) index ++;
    // If this is a 64-bit machine and we are using 32-bit words go down
	// one slot size, as all the slots are 2x in size.
    if ( index != 0 && ( sizeof(word_list) != sizeof(word) ) )
	{
		index -= 1;
	}
    return index;
}

static word_list* free_words[32] = { 0 };

word*
scfx_mant::alloc_word( std::size_t size )
{
    const int ALLOC_SIZE = 128;

    int slot_index = next_pow2_index( size );

    int alloc_size = ( 1 << slot_index );

    word_list*& slot = free_words[slot_index];

    if( ! slot )
    {
        slot = new word_list[ALLOC_SIZE * alloc_size];
	int i;
	for( i = 0; i < alloc_size*(ALLOC_SIZE-1) ; i+=alloc_size )
	{
	    slot[i].m_next_p = &slot[i+alloc_size];
	}
	slot[i].m_next_p = 0;
    }

    word* result = (word*)slot;
    free_words[slot_index] = slot[0].m_next_p;
    return result;
}

void
scfx_mant::free_word( word* array, std::size_t size )
{
    if( array && size )
    {
        int slot_index = next_pow2_index( size );
	word_list* wl_p = (word_list*)array;

	wl_p->m_next_p = free_words[slot_index];
	free_words[slot_index] = wl_p;
    }
}

} // namespace sc_dt


// Taf!