* [PATCH 02/12] Created RAND_32 and RAND_64 macros.
@ 2015-03-06 22:29 tyson.w.smith
0 siblings, 0 replies; only message in thread
From: tyson.w.smith @ 2015-03-06 22:29 UTC (permalink / raw)
To: davej; +Cc: trinity, Tyson Smith
From: Tyson Smith <tysmith@motorola.com>
These macros will generate a random number between 0 and 2^32 - 1 or
2^64 - 1 respectively. There is also a compile time check to verify
that a full 2^n bits of randomness will be generated (depends on RAND_MAX).
---
include/random.h | 8 ++++++++
random.c | 4 ++--
2 files changed, 10 insertions(+), 2 deletions(-)
diff --git a/include/random.h b/include/random.h
index dbff344..f070568 100644
--- a/include/random.h
+++ b/include/random.h
@@ -1,10 +1,18 @@
#pragma once
+#include <stdlib.h>
#include "child.h"
#include "types.h"
#define ONE_IN(x) ((rand() % x) == 0) // limit of RAND_MAX-1
+#if RAND_MAX == 0x7FFFFFFF
+#define RAND_32() ((rand() << 1) | (rand() & 1))
+#define RAND_64() (((0ULL | rand()) << 33) | ((0ULL | rand()) << 2) | (rand() & 0x3))
+#else
+#error "Unexpected RAND_MAX value. Please add support."
+#endif
+
extern unsigned int seed;
unsigned int init_seed(unsigned int seed);
void set_seed(struct childdata *child);
diff --git a/random.c b/random.c
index 6a2e90e..f425ed5 100644
--- a/random.c
+++ b/random.c
@@ -132,7 +132,7 @@ static unsigned int __rand32(void)
break;
case 1: r = randbits(32);
break;
- case 2: r = rand();
+ case 2: r = RAND_32();
break;
case 3: r = rand8x8();
break;
@@ -216,7 +216,7 @@ u64 rand64(void)
break;
case 1: r = randbits(64);
break;
- case 2: r = rand32() | rand32() << 31;
+ case 2: r = RAND_64();
break;
case 3: r = rand8x8();
break;
--
1.9.1
^ permalink raw reply related [flat|nested] only message in thread
only message in thread, other threads:[~2015-03-06 22:29 UTC | newest]
Thread overview: (only message) (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2015-03-06 22:29 [PATCH 02/12] Created RAND_32 and RAND_64 macros tyson.w.smith
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).