Tweaks to fmopl; same net effect overall, just faster.

Eliminate divisions, floating point, and mod operation from inner synth loop.

svn-id: r30896

2 files changed, 13 insertions, 1 deletions

diff --git a/common/util.cpp b/common/util.cpp
index 82a910f9a8..1f48a6ddd9 100644
--- a/common/util.cpp
+++ b/common/util.cpp
@@ -196,6 +196,12 @@ uint RandomSource::getRandomNumber(uint max) {
 	return _randSeed % (max + 1);
 }
 
+uint RandomSource::getRandomBit(void) {
+	_randSeed = 0xDEADBF03 * (_randSeed + 1);
+	_randSeed = (_randSeed >> 13) | (_randSeed << 19);
+	return _randSeed & 1;
+}
+
 uint RandomSource::getRandomNumberRng(uint min, uint max) {
 	return getRandomNumber(max - min) + min;
 }
diff --git a/common/util.h b/common/util.h
index e7a71ff42c..dd205f159c 100644
--- a/common/util.h
+++ b/common/util.h
@@ -83,7 +83,7 @@ bool matchString(const char *str, const char *pat);
 class StringTokenizer {
 public:
 	/**
-	 * Creates a StringTokenizer.	 
+	 * Creates a StringTokenizer.
 	 * @param str The string to be tokenized.
 	 * @param delimiters String containing all the delimiter characters (i.e. the characters to be ignored).
 	 * @note Uses space, horizontal tab, carriage return, newline, form feed and vertical tab as delimiters by default.
@@ -132,6 +132,12 @@ public:
 	 */
 	uint getRandomNumber(uint max);
 	/**
+	 * Generates a random unsigned integer in the interval [0, 1].
+	 * Identical to getRandomNumber(1), but faster, hopefully.
+	 * @return	a random number in the interval [0, max].
+	 */
+	uint getRandomBit(void);
+	/**
 	 * Generates a random unsigned integer in the interval [min, max].
 	 * @param min	the lower bound
 	 * @param max	the upper bound