/*
* $RANDOM support.
*
- * Copyright (C) 2008 Denys Vlasenko
+ * Copyright (C) 2009 Denys Vlasenko
*
- * Licensed under GPLv2, see file LICENSE in this tarball for details.
+ * Licensed under GPLv2, see file LICENSE in this source tree.
*/
+#ifndef SHELL_RANDOM_H
+#define SHELL_RANDOM_H 1
+
+PUSH_AND_SET_FUNCTION_VISIBILITY_TO_HIDDEN
typedef struct random_t {
- /* Random number generators */
- int32_t galois_LFSR; /* Galois LFSR (fast but weak). signed! */
- uint32_t LCG; /* LCG (fast but weak) */
+ /* State of random number generators: */
+
+ /* Galois LFSR (fast but weak) */
+ int32_t galois_LFSR; /* must be signed! */
+
+ /* LCG (fast but weak) */
+ uint32_t LCG;
+
+ /* 64-bit xorshift (fast, moderate strength) */
+ uint32_t xs64_x;
+ uint32_t xs64_y;
} random_t;
+#define UNINITED_RANDOM_T(rnd) \
+ ((rnd)->galois_LFSR == 0)
+
#define INIT_RANDOM_T(rnd, nonzero, v) \
- ((rnd)->galois_LFSR = (nonzero), (rnd)->LCG = (v))
+ ((rnd)->galois_LFSR = (rnd)->xs64_x = (nonzero), (rnd)->LCG = (rnd)->xs64_y = (v))
+
+#define CLEAR_RANDOM_T(rnd) \
+ ((rnd)->galois_LFSR = 0)
uint32_t next_random(random_t *rnd) FAST_FUNC;
+
+POP_SAVED_FUNCTION_VISIBILITY
+
+#endif