Changeset 8e7c9fe in mainline for uspace/lib/math/generic/trunc.c

Timestamp:

2014-09-12T03:45:25Z (11 years ago)

Author:

Jan Vesely <jano.vesely@…>

Branches:

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

Children:

c53b58e

Parents:

3eb0c85 (diff), 105d8d6 (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

most usb changes were reverted. blink and usbmass were fixed
known problems:
ehci won't initialize
usbmast asserts on unmount (happens on mainline too)

File:

• uspace/lib/math/generic/trunc.c (moved) (moved from kernel/arch/arm32/src/ddi/ddi.c ) (2 diffs)

uspace/lib/math/generic/trunc.c

@@ -1 +1 @@
 /*
- * Copyright (c) 2006 Jakub Jermar
+ * Copyright (c) 2014 Martin Decky
  * All rights reserved.
  *
@@ -27 +27 @@
  */
 
-/** @addtogroup arm32ddi
+/** @addtogroup libmath
  * @{
  */
 /** @file
- *  @brief DDI.
  */
 
-#include <ddi/ddi.h>
-#include <proc/task.h>
-#include <typedefs.h>
+#include <mathtypes.h>
+#include <trunc.h>
 
-/** Enable I/O space range for task.
+/** Truncate fractional part (round towards zero)
  *
- * Interrupts are disabled and task is locked.
+ * Truncate the fractional part of IEEE 754 double
+ * precision floating point number by zeroing fraction
+ * bits, effectively rounding the number towards zero
+ * to the nearest whole number.
  *
- * @param task Task.
- * @param ioaddr Startign I/O space address.
- * @param size Size of the enabled I/O range.
+ * If the argument is infinity or NaN, an exception
+ * should be indicated. This is not implemented yet.
  *
- * @return 0 on success or an error code from errno.h.
+ * @param val Floating point number.
+ *
+ * @return Number rounded towards zero.
+ *
  */
-int ddi_iospace_enable_arch(task_t *task, uintptr_t ioaddr, size_t size)
+float64 trunc_float64(float64 val)
 {
-        return 0;
+        int32_t exp = val.parts.exp - FLOAT64_BIAS;
+        
+        if (exp < 0) {
+                /* -1 < val < 1 => result is +0 or -0 */
+                val.parts.exp = 0;
+                val.parts.fraction = 0;
+        } else if (exp >= FLOAT64_FRACTION_SIZE) {
+                if (exp == 1024) {
+                        /* val is +inf, -inf or NaN => trigger an exception */
+                        // FIXME TODO
+                }
+                
+                /* All bits in val are relevant for the result */
+        } else {
+                /* Truncate irrelevant fraction bits */
+                val.parts.fraction &= UINT64_C(0x000fffffffffffff) >> exp;
+        }
+        
+        return val;
 }