Changeset ff381a7 in mainline for uspace/lib/math/generic/pow.c

Timestamp:

2015-11-02T20:54:19Z (8 years ago)

Author:

Jiri Svoboda <jiri@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

d8513177

Parents:

3feeab2 (diff), 5265eea4 (diff)
Note: this is a merge changeset, the changes displayed below correspond to the merge itself.
Use the (diff) links above to see all the changes relative to each parent.

Message:

Merge mainline changes.

File:

• uspace/lib/math/generic/pow.c (moved) (moved from uspace/lib/math/generic/mod.c ) (2 diffs)

uspace/lib/math/generic/pow.c

@@ -1 +1 @@
 /*
+ * Copyright (c) 2015 Jiri Svoboda
  * Copyright (c) 2014 Martin Decky
  * All rights reserved.
@@ -34 +35 @@
 
 #include <math.h>
-#include <mod.h>
+#include <pow.h>
 
-/** Double precision modulo
+/** Single precision power
  *
- * Calculate the modulo of dividend by divisor.
+ * Compute power value.
  *
- * This is a very basic implementation that uses
- * division and multiplication (instead of exact
- * arithmetics). Thus the result might be very
- * imprecise (depending on the magnitude of the
- * arguments).
+ * @param x Base
+ * @param y Exponent
  *
- * @param dividend Dividend.
- * @param divisor  Divisor.
- *
- * @return Modulo.
+ * @return Cosine value.
  *
  */
-float64_t float64_mod(float64_t dividend, float64_t divisor)
+float32_t float32_pow(float32_t x, float32_t y)
 {
-        // FIXME: replace with exact arithmetics
-        
-        float64_t quotient = trunc(dividend / divisor);
-        
-        return (dividend - quotient * divisor);
+        /* x^y = (e ^ log(x))^y = e ^ (log(x) * y) */
+        return exp_f32(log_f32(x) * y);
+}
+
+/** Double precision power
+ *
+ * Compute power value.
+ *
+ * @param x Base
+ * @param y Exponent
+ *
+ * @return Cosine value.
+ *
+ */
+float64_t float64_pow(float64_t x, float64_t y)
+{
+        /* x^y = (e ^ log(x))^y = e ^ (log(x) * y) */
+        return exp_f64(log_f64(x) * y);
 }