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/*********************************************************
* Copyright (C) 2002 VMware, Inc. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published
* by the Free Software Foundation version 2.1 and no later version.
*
* This program 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 Lesser GNU General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
*********************************************************/
#define INCLUDE_ALLOW_USERLEVEL
#define INCLUDE_ALLOW_VMCORE
#define INCLUDE_ALLOW_VMKERNEL
#include "includeCheck.h"
#include "vm_assert.h"
#include "vm_basic_types.h"
/*
* Defines util functions shared between the userlevel code and the monitor.
*/
/*
*----------------------------------------------------------------------
*
* Util_Throttle --
*
* Use for throttling of warnings.
*
* Results:
* Will return TRUE for an increasingly sparse set of counter values:
* 1, 2, ..., 100, 200, 300, ..., 10000, 20000, 30000, ..., .
*
* Side effects:
* None.
*
*----------------------------------------------------------------------
*/
Bool
Util_Throttle(uint32 count) // IN:
{
return count < 100 ||
(count < 10000 && count % 100 == 0) ||
(count < 1000000 && count % 10000 == 0) ||
count % 1000000 == 0;
}
/*
*----------------------------------------------------------------------
*
* Util_FastRand --
*
* Generates the next random number in the pseudo-random sequence
* defined by the multiplicative linear congruential generator
* S' = 16807 * S mod (2^31 - 1).
* This is the ACM "minimal standard random number generator".
* Based on method described by D.G. Carta in CACM, January 1990.
* Usage: provide previous random number as the seed for next one.
*
* Precondition:
* 0 < seed && seed < UTIL_FASTRAND_SEED_MAX
*
* Results:
* A random number.
*
* Side effects:
* None.
*
*----------------------------------------------------------------------
*/
uint32
Util_FastRand(uint32 seed)
{
uint64 product = 33614 * (uint64)seed;
uint32 product_lo = (uint32)(product & 0xffffffff) >> 1;
uint32 product_hi = product >> 32;
int32 test = product_lo + product_hi;
ASSERT(0 < seed && seed < UTIL_FASTRAND_SEED_MAX);
return (test > 0) ? test : (test & UTIL_FASTRAND_SEED_MAX) + 1;
}
#if defined(USERLEVEL) || defined(VMX86_DEBUG)
static uint32 crcTable[256];
static void
UtilCRCMakeTable(void)
{
uint32 c;
int n, k;
for (n = 0; n < 256; n++) {
c = (uint32) n;
for (k = 0; k < 8; k++) {
if (c & 1) {
c = 0xedb88320L ^ (c >> 1);
} else {
c = c >> 1;
}
}
crcTable[n] = c;
}
}
static INLINE_SINGLE_CALLER uint32
UtilCRCUpdate(uint32 crc,
const uint8 *buf,
int len)
{
uint32 c = crc;
int n;
static int crcTableComputed = 0;
if (!crcTableComputed) {
UtilCRCMakeTable();
crcTableComputed = 1;
}
for (n = 0; n < len; n++) {
c = crcTable[(c ^ buf[n]) & 0xff] ^ (c >> 8);
}
return c;
}
/*
*----------------------------------------------------------------------
*
* CRC_Compute --
*
* computes the CRC of a block of data
*
* Results:
*
* CRC code
*
* Side effects:
* Sets up the crc table if it hasn't already been computed.
*
*----------------------------------------------------------------------
*/
uint32
CRC_Compute(const uint8 *buf,
int len)
{
return UtilCRCUpdate(0xffffffffL, buf, len) ^ 0xffffffffL;
}
#endif /* defined (USERLEVEL) || defined(VMX86_DEBUG) */
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