* libs/libc/stdlib/lib_rand48.c
*
* SPDX-License-Identifier: Apache-2.0
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <stdlib.h>
#include <string.h>
#include <nuttx/lib/lib.h>
#include <nuttx/tls_task.h>
* Private Data
****************************************************************************/
* Private Functions
****************************************************************************/
#ifdef CONFIG_HAVE_LONG_LONG
static uint64_t rand48_step(FAR unsigned short int *xi,
FAR unsigned short int *lc)
{
uint64_t a;
uint64_t x;
x = xi[0] | ((xi[1] + 0ul) << 16) | ((xi[2] + 0ull) << 32);
a = lc[0] | ((lc[1] + 0ul) << 16) | ((lc[2] + 0ull) << 32);
x = a * x + lc[3];
xi[0] = x;
xi[1] = x >> 16;
xi[2] = x >> 32;
return x & 0xffffffffffffull;
}
#endif
* Public Functions
****************************************************************************/
* Name: srand48
****************************************************************************/
void srand48(long seed)
{
unsigned short int p[3];
p[0] = 0x330e;
p[1] = seed;
p[2] = seed >> 16;
seed48(p);
}
* Name: seed48
****************************************************************************/
FAR unsigned short int *seed48(FAR unsigned short int seed16v[3])
{
FAR struct task_info_s *info = task_get_info();
static unsigned short int p[3];
memcpy(p, info->ta_seed48, sizeof(p));
memcpy(info->ta_seed48, seed16v, sizeof(p));
return p;
}
* Name: lcong48
****************************************************************************/
void lcong48(FAR unsigned short int p[7])
{
FAR struct task_info_s *info = task_get_info();
memcpy(info->ta_seed48, p, sizeof(info->ta_seed48));
}
* Name: jrand48
*
* Description:
* Return signed long integers uniformly distributed over the
* interval [-2^31, 2^31).
*
****************************************************************************/
#ifdef CONFIG_HAVE_LONG_LONG
long jrand48(FAR unsigned short int s[3])
{
FAR struct task_info_s *info = task_get_info();
return (long)(rand48_step(s, info->ta_seed48 + 3) >> 16);
}
* Name: mrand48
*
* Description:
* Return signed long integers uniformly distributed over the
* interval [-2^31, 2^31).
*
****************************************************************************/
long mrand48(void)
{
FAR struct task_info_s *info = task_get_info();
return jrand48(info->ta_seed48);
}
* Name: nrand48
*
* Description:
* Return nonnegative long integers uniformly distributed over the
* interval [0, 2^31).
*
****************************************************************************/
long nrand48(FAR unsigned short int s[3])
{
FAR struct task_info_s *info = task_get_info();
return rand48_step(s, info->ta_seed48 + 3) >> 17;
}
* Name: lrand48
*
* Description:
* Return nonnegative long integers uniformly distributed over the
* interval [0, 2^31).
*
****************************************************************************/
long lrand48(void)
{
FAR struct task_info_s *info = task_get_info();
return nrand48(info->ta_seed48);
}
* Name: erand48
*
* Description:
* Return nonnegative double-precision floating-point values uniformly
* distributed over the interval [0.0, 1.0).
*
****************************************************************************/
# ifdef CONFIG_HAVE_DOUBLE
double erand48(FAR unsigned short int s[3])
{
FAR struct task_info_s *info = task_get_info();
union
{
uint64_t u;
double f;
} x;
x.u = 0x3ff0000000000000ull | rand48_step(s, info->ta_seed48 + 3) << 4;
return x.f - 1.0;
}
* Name: drand48
*
* Description:
* Return nonnegative double-precision floating-point values uniformly
* distributed over the interval [0.0, 1.0).
*
****************************************************************************/
double drand48(void)
{
FAR struct task_info_s *info = task_get_info();
return erand48(info->ta_seed48);
}
# endif
#endif