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/****************************************************************
* *
* Copyright 2001, 2007 Fidelity Information Services, Inc *
* *
* This source code contains the intellectual property *
* of its copyright holder(s), and is made available *
* under a license. If you do not know the terms of *
* the license, please stop and do not read further. *
* *
****************************************************************/
#include "mdef.h"
#include "gdsroot.h"
#include "gdsblk.h"
#include "gdsbml.h"
#define MAX_FFS_SIZE 32
/* Returns the location of the first set bit in the field. */
/* The search starts at the hint and does not wrap */
int4 bm_find_blk(int4 hint, sm_uc_ptr_t base_addr, int4 total_bits, boolean_t *used)
{
int4 bits;
sm_uc_ptr_t ptr, top;
unsigned char valid;
assert(hint < total_bits);
total_bits *= BML_BITS_PER_BLK;
/* Currently bm_find_blk has been coded to assume that if "hint" is
* non-zero then it is less than total_bits. We better assert that.
*/
if (hint)
{
ptr = base_addr + (hint * BML_BITS_PER_BLK) / 8;
top = base_addr + (total_bits + 7) / 8 - 1;
if (ptr == top)
{
bits = total_bits % 8;
if (bits == 6)
valid = *ptr & 63;
else if (bits == 4)
valid = *ptr & 15;
else if (bits == 2)
valid = *ptr & 3;
else
valid = *ptr;
}
else
valid = *ptr;
switch (hint % (8 / BML_BITS_PER_BLK))
{
case 0: break;
case 1: valid = valid & 252;
break;
case 2: valid = valid & 240;
break;
case 3: valid = valid & 192;
break;
}
if (valid)
{
if (valid & 1)
{
if (valid & 2)
*used = TRUE;
else
*used = FALSE;
return (int4)((ptr - base_addr) * (8 / BML_BITS_PER_BLK));
}
else if (valid & 4)
{
if (valid & 8)
*used = TRUE;
else
*used = FALSE;
return (int4)((ptr - base_addr) * (8 / BML_BITS_PER_BLK) + 1);
}
else if (valid & 16)
{
if (valid & 32)
*used = TRUE;
else
*used = FALSE;
return (int4)((ptr - base_addr) * (8 / BML_BITS_PER_BLK) + 2);
}
else
{
if (valid & 128)
*used = TRUE;
else
*used = FALSE;
return (int4)((ptr - base_addr) * (8 / BML_BITS_PER_BLK) + 3);
}
}
ptr++;
}
else
ptr = base_addr;
for (top = base_addr + (total_bits +7) / 8 - 1; ptr < top; ptr++)
{
if (*ptr)
{
if (*ptr & 1)
{
if (*ptr & 2)
*used = TRUE;
else
*used = FALSE;
return (int4)((ptr - base_addr) * (8 / BML_BITS_PER_BLK));
}
else if (*ptr & 4)
{
if (*ptr & 8)
*used = TRUE;
else
*used = FALSE;
return (int4)((ptr - base_addr) * (8 / BML_BITS_PER_BLK) + 1);
}
else if (*ptr & 16)
{
if (*ptr & 32)
*used = TRUE;
else
*used = FALSE;
return (int4)((ptr - base_addr) * (8 / BML_BITS_PER_BLK) + 2);
}
else
{ if (*ptr & 128)
*used = TRUE;
else
*used = FALSE;
return (int4)((ptr - base_addr) * (8 / BML_BITS_PER_BLK) + 3);
}
}
}
if ((ptr == top) && *ptr) /* Special processing for last byte--may be only partially valid , if had hint may */
{
bits = total_bits % 8; /* have already done last byte, then ptr will be greater than top */
if (bits == 6)
valid = *ptr & 63;
else if (bits == 4)
valid = *ptr & 15;
else if (bits == 2)
valid = *ptr & 3;
else
valid = *ptr;
if (valid)
{
if (valid & 1)
{
if (valid & 2)
*used = TRUE;
else
*used = FALSE;
return (int4)((ptr - base_addr) * (8 / BML_BITS_PER_BLK));
}
else if (valid & 4)
{
if (valid & 8)
*used = TRUE;
else
*used = FALSE;
return (int4)((ptr - base_addr) * (8 / BML_BITS_PER_BLK) + 1);
}
else if (valid & 16)
{
if (valid & 32)
*used = TRUE;
else
*used = FALSE;
return (int4)((ptr - base_addr) * (8 / BML_BITS_PER_BLK) + 2);
}
else
{
if (valid & 128)
*used = TRUE;
else
*used = FALSE;
return (int4)((ptr - base_addr) * (8 / BML_BITS_PER_BLK) + 3);
}
}
}
return -1;
}
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