Pull NuttX up to the 6.24 release.

Merge branch 'nuttx-merge-5447'

1 files changed, 277 insertions, 0 deletions

diff --git a/nuttx/libc/stdlib/lib_rand.c b/nuttx/libc/stdlib/lib_rand.c
new file mode 100644
index 000000000..453a4537a
--- /dev/null
+++ b/nuttx/libc/stdlib/lib_rand.c
@@ -0,0 +1,277 @@
+/****************************************************************************
+ * libc/stdlib/lib_rand.c
+ *
+ *   Copyright (C) 2007, 2011 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <gnutt@nuttx.org>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <sys/types.h>
+#include <stdlib.h>
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+/* First, second, and thired order congruential generators are supported */
+
+#ifndef CONFIG_LIB_RAND_ORDER
+#  define CONFIG_LIB_RAND_ORDER 1
+#endif
+
+#if CONFIG_LIB_RAND_ORDER > 3
+#  undef CONFIG_LIB_RAND_ORDER
+#  define CONFIG_LIB_RAND_ORDER 3
+#endif
+
+/* Values needed by the random number generator */
+
+#define RND1_CONSTK  470001
+#define RND1_CONSTP  999563
+#define RND2_CONSTK1 366528
+#define RND2_CONSTK2 508531
+#define RND2_CONSTP  998917
+#define RND3_CONSTK1 360137
+#define RND3_CONSTK2 519815
+#define RND3_CONSTK3 616087
+#define RND3_CONSTP  997783
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+
+static unsigned int nrand(unsigned int nLimit);
+
+/* First order congruential generators */
+
+static inline unsigned long fgenerate1(void);
+#if (CONFIG_LIB_RAND_ORDER == 1)
+static double_t frand1(void);
+#endif
+
+/* Second order congruential generators */
+
+#if (CONFIG_LIB_RAND_ORDER > 1)
+static inline unsigned long fgenerate2(void);
+#if (CONFIG_LIB_RAND_ORDER == 2)
+static double_t frand2(void);
+#endif
+
+/* Third order congruential generators */
+
+#if (CONFIG_LIB_RAND_ORDER > 2)
+static inline unsigned long fgenerate3(void);
+static double_t frand3(void);
+#endif
+#endif
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+static unsigned long g_randint1;
+#if (CONFIG_LIB_RAND_ORDER > 1)
+static unsigned long g_randint2;
+#if (CONFIG_LIB_RAND_ORDER > 2)
+static unsigned long g_randint3;
+#endif
+#endif
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+static unsigned int nrand(unsigned int nLimit)
+{
+  unsigned long result;
+  double_t ratio;
+
+  /* Loop to be sure a legal random number is generated */
+
+  do
+    {
+      /* Get a random integer in the requested range */
+
+#if (CONFIG_LIB_RAND_ORDER == 1)
+      ratio = frand1();
+#elif (CONFIG_LIB_RAND_ORDER == 2)
+      ratio = frand2();
+#else /* if (CONFIG_LIB_RAND_ORDER > 2) */
+      ratio = frand3();
+#endif
+
+      /* Then, produce the return-able value */
+
+      result = (unsigned long)(((double_t)nLimit) * ratio);
+    }
+  while (result >= (unsigned long)nLimit);
+
+  return (unsigned int)result;
+}
+
+/* First order congruential generators */
+
+static inline unsigned long fgenerate1(void)
+{
+  unsigned long randint;
+
+  /* First order congruential generator.  One may be added to the result of the
+   * generated value to avoid the value zero.  This would be fatal for the
+   * first order random number generator.
+   */
+
+  randint    = (RND1_CONSTK * g_randint1) % RND1_CONSTP;
+  g_randint1 = (randint == 0 ? 1 : randint);
+  return randint;
+}
+
+#if (CONFIG_LIB_RAND_ORDER == 1)
+static double_t frand1(void)
+{
+  /* First order congruential generator. */
+
+  unsigned long randint = fgenerate1();
+
+  /* Construct an floating point value in the range from 0.0 up to 1.0 */
+
+  return ((double_t)randint) / ((double_t)RND1_CONSTP);
+}
+#endif
+
+/* Second order congruential generators */
+
+#if (CONFIG_LIB_RAND_ORDER > 1)
+static inline unsigned long fgenerate2(void)
+{
+  unsigned long randint;
+
+  /* Second order congruential generator. */
+
+  randint    = (RND2_CONSTK1 * g_randint1 +
+                RND2_CONSTK2 * g_randint2) % RND2_CONSTP;
+
+  g_randint2 = g_randint1;
+  g_randint1 = randint;
+
+  /* We cannot permit both values to become zero.  That would be fatal for the
+   * second order random number generator.
+   */
+
+  if (g_randint2 == 0 && g_randint1 == 0)
+    {
+      g_randint2 = 1;
+    }
+
+  return randint;
+}
+
+#if (CONFIG_LIB_RAND_ORDER == 2)
+static double_t frand2(void)
+{
+  /* Second order congruential generator */
+
+  unsigned long randint = fgenerate2();
+
+  /* Construct an floating point value in the range from 0.0 up to 1.0 */
+
+  return ((double_t)randint) / ((double_t)RND2_CONSTP);
+}
+#endif
+
+/* Third order congruential generators */
+
+#if (CONFIG_LIB_RAND_ORDER > 2)
+static inline unsigned long fgenerate3(void)
+{
+  unsigned long randint;
+
+  /* Third order congruential generator. */
+
+  randint    = (RND3_CONSTK1 * g_randint1 +
+                RND3_CONSTK2 * g_randint2 +
+                RND3_CONSTK2 * g_randint3) % RND3_CONSTP;
+
+  g_randint3 = g_randint2;
+  g_randint2 = g_randint1;
+  g_randint1 = randint;
+
+  /* We cannot permit all three values to become zero.  That would be fatal for the
+   * third order random number generator.
+   */
+
+  if (g_randint3 == 0 && g_randint2 == 0 && g_randint1 == 0)
+    {
+      g_randint3 = 1;
+    }
+
+  return randint;
+}
+
+static double_t frand3(void)
+{
+  /* Third order congruential generator */
+
+  unsigned long randint = fgenerate3();
+
+  /* Construct an floating point value in the range from 0.0 up to 1.0 */
+
+  return ((double_t)randint) / ((double_t)RND3_CONSTP);
+}
+#endif
+#endif
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Function:  srand, rand
+ ****************************************************************************/
+
+void srand(unsigned int seed)
+{
+  g_randint1 = seed;
+#if (CONFIG_LIB_RAND_ORDER > 1)
+  g_randint2 = seed;
+  (void)fgenerate1();
+#if (CONFIG_LIB_RAND_ORDER > 2)
+  g_randint3 = seed;
+  (void)fgenerate2();
+#endif
+#endif
+}
+
+int rand(void)
+{
+  return (int)nrand(32768);
+}